Ld Naturcil With Calcium by Direct NutriSciences Inc.

EFFECTIVE

• Constipation. Oral blond psyllium is effective as a bulk laxative for reducing constipation and for softening stools. Details: Blond psyllium, in doses of 7 grams to 24 grams daily in single or divided doses for up to 8 weeks, has been used for the treatment or prevention of constipation (8424,9423,10092,22969,22970,22972,22973,99501). Some evidence suggests that blond psyllium alone for 7 days can relieve constipation and improve stool consistency as effectively as preparations containing blond psyllium 6.5 grams plus senna 1.5 grams daily (8424) or docusate sodium (10088). However, some preliminary evidence suggests that taking blond psyllium is less effective than prunes for increasing stool frequency in patients with constipation (22973). Taking blond psyllium-containing combination products also seems to reduce constipation. Some clinical evidence suggests that taking a combination product containing blond psyllium, aloe vera, and celandine daily for 28 days can improve stool frequency and stool softness and decrease laxative dependence when compared with placebo in people with chronic constipation (22974). Other clinical research suggests that taking a combination containing blond psyllium 17.3%, acacia fiber 67.7%, and fructose at a total daily dose of 16.8-22.4 grams daily for 8 weeks can improve symptoms of constipation in 78% of children with chronic functional constipation (22975).

LIKELY EFFECTIVE

• Coronary heart disease (CHD). Consuming products containing soluble fiber, such as blond psyllium, may reduce the risk of CHD when used as part of a diet low in saturated fat and cholesterol. Details: In 1998, the FDA authorized a health claim stating that the addition of soluble fiber, such as that from blond psyllium, to a diet low in saturated fat and cholesterol might reduce the risk of CHD. The daily dietary intake of psyllium husk must be 7 grams or more (93216).
• Hyperlipidemia. Oral blond psyllium reduces levels of low-density lipoprotein (LDL) cholesterol in most patients with mild to moderate hypercholesterolemia. It is unclear if blond psyllium is beneficial in older adults. Details: Blond psyllium seed husk or seed, added to food or as a separate supplement in a dose of 3-20 grams daily, in combination with a low-fat or a high-fat diet, can reduce levels of total cholesterol by 3% to 14%, LDL cholesterol by 5% to 11%, and apolipoprotein B by 8.8% after 7 weeks or more of treatment. It also reduces the LDL to high-density lipoprotein (HDL) ratio after 6 months of treatment (1376,2324,2327,4971,6261,6262,8060,8061,8066,10095) (22984,22986,22987,22988,22989,22990,22992,22993,22994,22995)(22996). There is evidence the LDL:HDL ratio can be reduced further when blond psyllium is consumed with a diet containing approximately 12% of energy as monounsaturated fatty acids and 29% as total fat (8067). However, taking blond psyllium 6 grams or less daily may not be effective for lowering cholesterol (22998). Also, there is some evidence that it lowers LDL cholesterol levels to a lesser degree in patients 60 years or older when compared with younger patients (2326). Blond psyllium does not significantly increase HDL levels and may actually lower HDL cholesterol levels in some patients. However, the magnitude of change in the HDL level is much less than changes in total and LDL cholesterol levels (1376,8433,10095). While some evidence suggests that blond psyllium reduces triglycerides (22993), other evidence shows no benefit (13102). Blond psyllium has also been used in cereal or cookies or in mixtures of soluble fibers, such as pectin, guar gum, carob gum, and/or oats, providing up to 15 grams of soluble fiber daily for up to 8 weeks (1584,6263,8060,8061,8431,8432,22988,22992). In fact, blond psyllium seems to be most effective when consumed with foods at mealtime (8062). Breakfast cereal containing blond psyllium can modestly decrease total cholesterol and LDL cholesterol by 5% and 9%, respectively (1584,6263,8060,8061). When used in conjunction with guar gum, carob gum, or oats for 56 months, it reduces total cholesterol by 6.4% and LDL cholesterol by 10.5% (8431). Some evidence suggests that blond psyllium seed might be more effective than the seed husk for lowering cholesterol (8069) and increasing levels of HDL cholesterol (92198). Blond psyllium has also been studied in combination with cholesterol-lowering medications. In one study, patients taking a combination of simvastatin 10 mg and blond psyllium (Metamucil) daily had similar reductions in cholesterol as those taking only simvastatin 20 mg daily (13102). Also, a combination of blond psyllium with colestipol, at half the usual doses, seems to be as effective as colestipol alone (8432). Blond psyllium also seems to reduce colestipol and cholestyramine side effects such as constipation and abdominal pain (8432,9424). In children with hypercholesterolemia, psyllium supplementation can further decrease LDL cholesterol levels by 7% to 15% when added to the low-fat, low-cholesterol, National Cholesterol Education Program (NCEP) Step 1 diet. However, psyllium supplementation added to the more stringent NCEP Step 2 diet may have less of an additional effect on LDL cholesterol (8073,8074,8075,8076). Blond psyllium 3.2-10 grams daily in cereal for up to 12 weeks has been used in children aged 2-18 years, in combination with a low-fat, low-cholesterol diet. Younger children aged 2-5 years used lower amounts of 3.2 grams daily while children aged 6-18 years used up to 10 grams daily (8075,8076). However, a small study in obese school children 15-19 years old shows that taking a specific psyllium powder (Natural Psyllium Fiber, Kirkland Signature) orally 10 grams daily for 7 weeks does not reduce LDL cholesterol, HDL cholesterol, or triglyceride levels when compared with placebo (106859).

POSSIBLY EFFECTIVE

• Diabetes. Oral blond psyllium seems to be beneficial for improving glycemic control in people with type 1 or type 2 diabetes. It is unclear if blond psyllium is beneficial for the prevention of type 2 diabetes. Details: Taking blond psyllium seed husk 10.2-22 grams daily in divided doses for 8-20 weeks reduces postprandial serum glucose, insulin levels, serum total cholesterol, and low-density lipoprotein (LDL) cholesterol levels in patients with type 2 diabetes and hypercholesterolemia (1405,8058,8064,10091,10099,12552,22963,22964). Blond psyllium reduces postprandial blood glucose levels by about 14% to 20%, total cholesterol by about 9%, and LDL cholesterol by 13% (1405,8058). In a meta-analysis of 8 studies in people with type 2 diabetes, blond psyllium 3.4-15 grams daily for 8-20 weeks was associated with significant reductions in fasting blood glucose, glycated hemoglobin (HbA1c), LDL cholesterol, and triglycerides; however, it did not affect body weight, body mass index, total cholesterol, or high-density lipoprotein (HDL) cholesterol (102828). Blond psyllium also seems to lower postprandial glucose levels in patients with type 1 diabetes (12553,12554). The maximum effect of blond psyllium on glucose levels occurs when psyllium is mixed and consumed with foods (8064,10091). Evidence is mixed over whether blond psyllium lowers postprandial glucose in people who do not have diabetes (9249,22965,110762). The FDA has allowed a qualified health claim stating that psyllium husk may reduce the risk of developing type 2 diabetes. However, the FDA has concluded that there is very little scientific evidence supporting this claim (102827).
• Diarrhea. Oral blond psyllium seems to be beneficial for the treatment of most types of diarrhea. However, it is unclear if blond psyllium is beneficial for tube feed-related diarrhea. Details: Taking blond psyllium orally seems to delay gastric emptying, slow colonic transit, increase fecal viscosity, and improve fecal consistency in patients with diarrhea (5246,8419,8420,8421). Clinical research shows that taking psyllium 7-18 grams daily in divided doses for up to 7 days, alone or in combination with calcium carbonate and calcium phosphate 1 gram each daily in a weight ratio of 4:1:1, seems to be as effective as loperamide in reducing the frequency and urgency associated with diarrhea (5246,8419,8420,8421,8422). Also, preliminary clinical research shows that blond psyllium 6.5 grams three times daily might also be useful in treating post-cholecystectomy diarrhea (10097). Additionally, taking blond psyllium orally seems to reduce diarrhea associated with the use of misoprostol. There is preliminary evidence that blond psyllium 3.4 grams twice daily relieves diarrhea associated with misoprostol use and prevents its reoccurrence when used throughout misoprostol therapy (8429). However, the research for tube feed-related diarrhea is mixed (8423,9422,102829). In patients receiving enteral tube feedings, psyllium does not decrease the frequency of stools (8423,9422). Other preliminary clinical research shows that adding a specific blond psyllium product (Mucilin SF, Paradigm Pharmaceuticals Inc.), as 15.2 grams per liter of an enteral nutrition formula does not reduce the number of days of diarrhea (102829). Conversely, some research suggests blond psyllium 14 grams daily in divided doses for 7 days may decrease the number of liquid stools (8423,9422).
• Hemorrhoids. Oral blond psyllium seems to be beneficial for hemorrhoid symptoms. Details: Taking blond psyllium orally seems to help relieve bleeding and pain in people with hemorrhoids (8077,22961,22962). One clinical trial suggests that taking blond psyllium seed fiber (Vi-Siblin) 6.6 grams before each meal daily for 6 weeks can decrease bleeding and pain upon defecation when compared with placebo in people with symptomatic hemorrhoids (22961). Another clinical trial suggests that taking blond psyllium (Metamucil) 3.9 grams three times daily for 40 days can decrease bleeding when compared with a B vitamin control supplement in people with internal bleeding hemorrhoids (22962). Additionally, a preliminary clinical trial suggests that psyllium husk 3.5 grams twice daily used with micronized purified flavonoid fraction (MPFF, Daflon) 1500 mg twice daily for 5 days, followed by 1000 mg twice daily for 3 weeks can relieve bleeding more rapidly than psyllium husk used alone or psyllium husk used with rubber band ligation in patients with non-prolapsed hemorrhoids (8077).
• Irritable bowel syndrome (IBS). Oral blond psyllium seems to be beneficial for reducing symptoms in adults and children with IBS. Details: While some evidence shows no benefit (8425,22981), the majority of evidence shows that blond psyllium seed husk can relieve constipation and improve abdominal pain, diarrhea, and overall well-being in patients with IBS (2316,8426,8427,8428,22976,22977,22978,22979,22980). One meta-analysis of clinical trials suggests that blond psyllium can reduce the risk of persistent IBS symptoms by 22% when compared with placebo (22982). These studies have used blond psyllium 6.4-30 grams daily in divided doses for up to 4 months (2316,8426,8427,22976,22978,22979,22982). There is also some evidence that a combination of blond psyllium 10 grams twice daily and propantheline (Pro-Banthine) 15 mg three times daily relieves constipation, incomplete bowel evacuation, abdominal pain, constipation, and straining associated with IBS. Patients typically experience relief after four weeks of treatment (8428). However, taking blond psyllium with mebeverine does not seem to improve symptoms of IBS when compared to mebeverine taken with a high fiber diet (22983). There is also evidence that blond psyllium may benefit children with IBS. A moderate-size clinical study in pediatric patients in India with IBS shows that taking blond psyllium husk 3-6 grams twice daily for 4 weeks leads to symptom remission in about 44% of patients compared with 10% of patients who took placebo (110763). However, it is unclear if these benefits can be extrapolated to patients in other geographic locations.
• Orlistat (Xenical, Alli) side effects. Oral blond psyllium seems to be beneficial for reducing orlistat side effects. Details: Taking blond psyllium 18 grams daily with each dose of orlistat for 30 days seems to relieve orlistat side effects such as flatulence, stomach rumbling (borborygmi), abdominal cramps, oily spotting, and fecal incontinence without decreasing the weight-reducing effect of orlistat (5245).

POSSIBLY INEFFECTIVE

• Colorectal adenoma. Oral blond psyllium does not seem to be beneficial for preventing colorectal adenoma recurrence. Details: Taking blond psyllium orally 3.5 grams per day does not seem to reduce the risk of colorectal adenoma recurrence. There is some evidence that it might actually increase the risk of adenoma recurrence, particularly in people with high dietary calcium intake. However, more evidence is needed to determine the relationship of psyllium and calcium to colorectal adenoma (7585).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Colorectal cancer. It is unclear if dietary blond psyllium is beneficial for colorectal cancer. Details: Population research suggests that higher dietary intake of blond psyllium is associated with reduced mortality from colorectal cancer (92197).
• Crohn disease. Oral blond psyllium has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients with Crohn disease shows that taking blond psyllium 9.9 grams daily along with Lactobacillus- and Bifidobacterium-containing probiotics 75 billion colony forming units daily for an average of 13 months can decrease disease activity and symptom scores when compared to baseline. Overall, 70% of subjects in the study showed an improvement in clinical symptoms (22968). However, the validity of these findings is limited by the lack of a control group.
• Dry eye. It is unclear if blond psyllium eye drops are beneficial for dry eye. Details: In patients with dry eye, clinical research shows that use of eye drops providing blond psyllium mucilage polysaccharides 0.35 mcg/mL four times daily for 6 weeks improves subjective symptoms of dry eye by 62%, compared with a 15% improvement in those using placebo drops. There were also improvements in light sensitivity, grittiness, burning, and blurred vision, but the eye drops did not affect objective symptoms including tear film break up time, tear production, or tear osmolarity (105274).
• Fecal incontinence. It is unclear if blond psyllium is beneficial for patients with this condition. Details: A small clinical study in adults with fecal incontinence and loose stools suggests that taking blond psyllium 6 grams daily for 4 weeks does not improve the proportion of patients with at least 50% reduction in incontinence episodes when compared with a dietician-led low fermentable oligosaccharide, disaccharide, monosaccharide, and polyol (FODMAP) diet (110761).
• Gastroesophageal reflux disease (GERD). It is unclear if oral blond psyllium is beneficial for GERD. Details: Preliminary clinical research shows that taking a specific blond psyllium supplement (Mucofalk, Dr. Falk PharmaGmbH) 5 grams three times daily mixed in 150 mL of water for 10 days may help control symptoms in some patients with GERD. About 60% of patients achieved at least 7 consecutive days of no reflux after taking blond psyllium (99500). The validity of these results is limited by the lack of a control group.
• Hypertension. It is unclear if oral blond psyllium is beneficial for hypertension. Details: Preliminary clinical research shows that blond psyllium 3.5 grams taken three times daily for 6 months can reduce both systolic and diastolic blood pressure when compared with pretreatment in overweight patients with hypertension (54260). A small clinical study shows that taking blond psyllium 15 grams with soy protein 66 grams daily for 8 weeks can help reduce systolic and diastolic blood pressure by about 6 mmHg and 2 mmHg, respectively, in hypertensive adults (10458). In a meta-analysis of 11 trials using psyllium 3.7-15 grams daily for 1-6 months, the overall weighted mean reduction in systolic blood pressure was 2 mmHg, with only 3 trials reporting a significant reduction. Only one trial reported a significant reduction in diastolic blood pressure (102826). This improvement in systolic blood pressure appears to only occur with a study duration of 8 weeks or longer, and the level of effect seems to be related to baseline blood pressure. It is not clear if any reduction in blood pressure achieved with psyllium would be considered clinically significant. Additionally, it is unclear if the studies included in this meta-analysis used blond psyllium or black psyllium supplements.
• Kidney failure. Although there has been interest in using oral blond psyllium to improve outcomes in kidney failure, there is insufficient reliable information about the clinical effects of blond psyllium for this purpose.
• Obesity. It is unclear if oral blond psyllium can improve weight loss in overweight or obese adolescents and adults; the available research is conflicting. Details: Some preliminary clinical research shows that blond psyllium might reduce body weight and appetite in adults who are overweight or obese. In one clinical trial, taking blond psyllium 12 grams three times daily for 12 weeks reduced body weight, body mass index (BMI), and body fat percentage when compared with placebo in overweight and obese individuals (23402). In obese individuals, another clinical trial shows that taking psyllium along with a specific diet reduces body weight and appetite when compared with the specific diet alone (23403). However, a meta-analysis of 22 trials using psyllium 1.7-21 grams daily for 2-36 weeks shows that psyllium does not have a significant effect on body weight, BMI, or waist circumference in overweight or obese adults, although several sources of heterogeneity are present in the trials (102825). A small clinical study in school children 15-19 years old with obesity and at least 1 other cardiovascular risk factor shows that taking a specific psyllium powder (Natural Psyllium Fiber, Kirkland Signature) orally 10 grams daily for 7 weeks reduces body mass index (BMI) and waist circumference by 2% and 0.5%, respectively, when compared with baseline, but not when compared with placebo (106859).
• Oral mucositis. It is unclear if rinsing the mouth with blond psyllium is beneficial for oral mucositis prevention. Details: In patients with breast cancer who had developed oral mucositis during the previous chemotherapy cycle, a small clinical trial shows that using a mouthwash containing a mixture of blond psyllium husk 500 mg in 30 mL water with three drops of vinegar three times daily, starting during a later chemotherapy cycle and continuing for 2 weeks, modestly reduces the degree of mucositis, severity of pain, and xerostomia grade when compared with a placebo mouthwash (105273).
• Postoperative bowel function. It is unclear if taking oral blond psyllium preoperatively reduces the time to the first bowel movement after surgery. Details: A moderate-size clinical study in patients undergoing surgery for pelvic organ prolapse shows that taking blond psyllium (Metamucil) 3.4 g twice daily for 7 days prior to surgery, followed by a usual postoperative bowel regimen, does not reduce the time to the first bowel movement after surgery or pain due to the first postoperative bowel movement when compared with usual care (110764).
• Ulcerative colitis. It is unclear if oral blond psyllium is beneficial for ulcerative colitis. Details: One small clinical study shows that taking blond psyllium seeds 10 grams twice daily might be as effective as mesalamine 500 mg three times daily for 12 months in preventing the relapse of ulcerative colitis (2385). However, this dose of mesalamine is much lower than what is typically used for this indication. Another small clinical trial shows that blond psyllium 3.5 grams twice daily for 4 months also appears to relieve gastrointestinal symptoms in adult patients with ulcerative colitis in remission, including abdominal pain, diarrhea, loose stools, urgency, bloating, incomplete evacuation, mucus discharge, and constipation (10086). However, the authors were unable to rule out the presence of irritable bowel syndrome (IBS) this population. A small clinical study in patients with juvenile ulcerative colitis in remission shows that blond psyllium does not appear to have an effect on fecal bile acid excretion, an indicator of disease progression (10090). More evidence is needed to rate the effectiveness of blond psyllium for these uses.

(Read more about BLOND PSYLLIUM)

EFFECTIVE

• Dyspepsia. Oral calcium carbonate is approved by the US Food and Drug Administration (FDA) as an antacid. Details: Taking calcium carbonate orally as an antacid is effective for treating dyspepsia (1843). Calcium carbonate has FDA approval as an antacid.
• Hyperkalemia. Intravenous calcium gluconate is approved by the US Food and Drug Administration (FDA) for preventing hyperkalemia-induced cardiac abnormalities. Details: Administering calcium gluconate intravenously can reverse electrocardiographic changes and arrhythmias induced by hyperkalemia (12946). Intravenous calcium gluconate is FDA-approved for preventing hyperkalemia-induced cardiac abnormalities.
• Hypocalcemia. Oral calcium treats and prevents hypocalcemia. Intravenous calcium is used to treat severe hypocalcemia. Details: Taking calcium orally is effective for treating and preventing hypocalcemia. Intravenous calcium gluconate, acetate, gluceptate, or chloride is effective for severe hypocalcemia or hypocalcemic tetany (12928).
• Kidney failure. Oral calcium carbonate or calcium acetate is used as a phosphate binder during kidney failure. Details: Taking calcium carbonate or calcium acetate orally is effective as a phosphate binder. Calcium acetate (PhosLo) appears to control hyperphosphatemia better than sevelamer (Renagel) (12943,12944,38990). Calcium citrate is not recommended for this purpose because it increases aluminum absorption and does not bind phosphate as efficiently as calcium acetate or calcium carbonate (21631). Some clinical research also shows that taking calcium orally reduces blood pressure in patients with kidney failure (975).

LIKELY EFFECTIVE

• Corticosteroid-induced osteoporosis. Oral calcium in combination with vitamin D prevents bone density loss that occurs during long-term treatment with corticosteroids. Details: Taking calcium in combination with vitamin D as adjunctive therapy seems to be effective for reducing bone mineral density loss in people using corticosteroids long-term (982,1046,1830,1831,1832,4462,4463,4464,4465,4466)(4467,12945,38493). One specific product used in clinical research is Oscal (Marion Merrel Dow Inc.), which contains elemental calcium 500 mg per tablet plus vitamin D 125 IU per tablet (982). Another product used is Oscal 250 + D (SmithKline Beecham Healthcare), which contains elemental calcium 250 mg and vitamin D 125 IU per tablet (1046).
• Hyperparathyroidism. Oral calcium reduces parathyroid hormone levels in patients with secondary hyperparathyroidism due to kidney failure. Details: Taking calcium orally reduces parathyroid hormone levels in patients with kidney failure and secondary hyperparathyroidism (1827,1828,1829,39174,39425). In elderly women, the combination of calcium and vitamin D reverses secondary hyperparathyroidism and reduces hip fracture risk (8818). Also, population research suggests increased calcium intake from the diet and supplements reduces the risk of primary hyperparathyroidism in women. Supplemental intakes of at least 500 mg/day and dietary intakes of approximately 1100 mg/day are considered to be protective (91353).
• Osteoporosis. Adequate calcium intake, from the diet and/or supplements, is recommended for the prevention and treatment of osteoporosis. Details: The Bone Health and Osteoporosis Foundation (BHOF) recommends ensuring adequate calcium intake in line with the recommended dietary allowance (RDA) by age, along with adequate vitamin D intake, for the prevention and treatment of osteoporosis in adults over 50 years of age. Supplementation can be used to augment dietary intake when adequate dietary intake is not feasible (109425). In the US and Canada, foods containing at least 200 mg calcium with less phosphorous content than calcium can be labelled with a health claim regarding the relationship between adequate calcium intake and a reduced risk for osteoporosis (11940,102148). However, calcium supplementation is not recommended specifically for the primary prevention of osteoporosis. The US Preventive Task Force (USPSTF) states that the current evidence is insufficient to assess the balance of benefits and harms of vitamin D and calcium supplementation, alone or in combination, for the primary prevention of fractures in community dwelling adults without osteoporosis (95695). Also, calcium supplements do not seem to be effective for preventing loss of bone mineral density (BMD) during lactation (988), in patients who have had bone marrow transplantation (1817), or in patients who have had renal transplantation (4823,38736,38871). Maximal bone growth occurs in the teenage years, and then BMD in females remains relatively constant until age 30-40. After age 40, bone loss typically occurs at rates of 0.5% to 1% per year. In males, this occurs several decades later. Bone loss is more pronounced if dietary calcium intake is below the RDA, which is the case for many Americans (2571,2578). One meta-analysis of randomized controlled trials in healthy children 7-14 years old shows that fortifying food with calcium 250-1000 mg daily for up to 24 months modestly improves femoral neck BMD, but not hip or spine BMD. However, the included trials did not supplement vitamin D (107232). During the 5 years immediately after menopause, calcium supplementation has very little effect on bone loss (2569,2570,2575,2576). The rapid loss of estrogen causes a high bone resorption rate, which increases serum calcium levels and therefore decreases intestinal absorption of calcium (2570). After this period, the typical rate of bone loss is 2% per year (2572,2576). Taking calcium 1000-1600 mg daily as carbonate, citrate, lactate gluconate, or citrate malate salt decreases this rate by 0.25% to 1% annually (977,979,981,2569,2571,2572,2575,2576,2578,6850)(38978,38980,39064). The greatest reductions (1% or more) are seen in the first 1-2 years of supplementation when bone remodeling foci can be filled (2569,2576). After this period, the differences in rate of loss between supplemented and non-supplemented females are closer to 0.25% per year (2569,2577). A meta-analysis of clinical evidence suggests that there is no additional benefit after 4 years (38980). Small clinical studies have found that continuous calcium supplementation at an average daily dose of 1050 mg, started after menopause and continued for 1.5-4 years, may reduce fracture rates by 26% when compared with no calcium supplementation. The largest of these studies was conducted in nursing home residents who also received daily vitamin D; the benefits of calcium, specifically, are unclear (39386). Some research also suggests that calcium and vitamin D improves primary prevention of osteoporotic fractures in some older individuals with osteoporosis, particularly the elderly and those who are no longer community dwelling (12930,38875,38849,39026,109471). However, not all research is positive. One large clinical trial in elderly adults with a low-trauma fracture show that taking calcium 1000 mg daily with or without vitamin D 800 IU daily for 2-7 years does not reduce the risk of a second fracture when compared with placebo (13073). Another clinical study shows that taking calcium 1000 mg daily plus vitamin D 800 IU daily does not prevent a second fracture in elderly patients, or prevent a first fracture in elderly patients with other risk factors such as low body weight (less than 58 kg, 127.6 pounds), smoking, family history of hip fracture, or fair or poor self-reported health (12929). Also, some exploratory research suggests that supplements may need to be continued indefinitely; in adults over 68 years of age, any effects of 2 years of calcium supplements on BMD appear to be lost within 2 years after discontinuing supplements (6853). Calcium has additive effects when used with other agents such as vitamin D, estrogens, or calcitonin. Whereas calcium alone generally reduces or prevents loss of BMD, combination with other agents can produce small increases in BMD ranging from 0.3% to 3.3% depending on the combination and dosages used (978,980,1836,2570,2571,2572,2576). However, one meta-analysis in healthy adults shows that fortifying foods with calcium 250-1000 mg daily, in conjunction with vitamin D supplementation, for up to 24 months does not improve BMD when compared with control (107232). The full potential of osteoporosis treatments cannot be realized without adequate calcium intake (2569,2570,2571,2572). Advise patients taking agents such as estrogens, calcitonin, bisphosphonates, or raloxifene (Evista) to ensure that their daily calcium intake meets the RDA. Use supplements if necessary. The usefulness of calcium in preventing osteoporosis in males is not as well-studied. Some observational research has found that calcium 870 mg daily is not associated with changes in BMD and bone loss in males (97201). However, clinical evidence suggests that taking calcium 1000 mg daily for 2 years might improve trabecular or cortical bone mass by 2% to 4% (980,8827,8873). Dietary supplementation with calcium and vitamin D seems to moderately reduce bone loss measured in the femoral neck, spine, and total body, and seems to reduce the incidence of nonvertebral fractures in older patients with osteopenia or low BMD (980).
• Premenstrual syndrome (PMS). Adequate calcium intake seems to prevent symptoms of PMS. Details: There seems to be a link between low dietary calcium intake and symptoms of PMS (2004,6847,39007). Taking calcium 1000-1336 mg daily seems to significantly reduce depressed mood, water retention, and pain, especially if daily calcium intake is inadequate (1822,1823,1824,2004,95821). Calcium carbonate 1200 mg daily seems to decrease PMS symptom scores by about 18% when compared with placebo (1822). Increasing dietary calcium intake is also associated with a decreased risk of developing PMS. Consuming an average of 1283 mg of calcium per day from foods is associated with about a 30% lower risk of developing PMS compared with consuming an average of 529 mg daily (13094); however, taking calcium supplements does not appear to be associated with the risk of developing PMS.

POSSIBLY EFFECTIVE

• Colorectal cancer. Oral calcium seems to be beneficial for preventing colorectal cancer, especially in those with adequate vitamin D levels and normal body mass index (BMI). Details: Population studies have found that increased intake of dietary or supplemental calcium is associated with a reduced risk of colorectal cancer and colorectal adenomas (1047,8820,12120,38951,98898,98899). Clinical trials and meta-analyses of clinical research also show that taking calcium supplements 1.2-2 grams daily for up to 4 years can reduce the risk of colorectal adenoma recurrence by up to 29% (970,12118,12950,15267,34596,38718,39042,95817). However, not all research has been positive. Some meta-analyses of clinical research or observational studies suggest that taking calcium does not reduce the risk of familial adenomatous polyposis or colorectal cancer (34596,39042,39349). Other contradictory research suggests that postmenopausal females who take calcium 1000 mg daily plus vitamin D 400 IU daily do not have a reduced risk of developing colorectal cancer (14290); however, this finding may not be reliable due to the high baseline intake of calcium in study participants. The reason for these conflicting findings is not entirely clear. Vitamin D might be an important factor. People with lower than average vitamin D levels do not seem to get any benefit from calcium supplements (12118). Also, one meta-analysis of previous trials suggests that taking calcium 1200 mg daily reduces the risk of colorectal adenomas in people with a normal BMI, but not in those who are overweight or obese (99715). Despite this conflicting evidence, the US Food and Drug Administration (FDA) approved a qualified health claim in 2005 stating that calcium supplements may reduce the risk of colorectal cancer and colorectal adenomas. However, the FDA has determined that there is little scientific evidence to support this claim (102366).
• Fetal bone mineralization. If calcium intakes are low during pregnancy, oral calcium seems to be beneficial for increasing fetal bone density. Details: With low dietary calcium intake (less than 562 mg elemental calcium daily) during pregnancy, calcium supplementation increases fetal bone mineralization and density. However, calcium supplementation does not offer any additional benefit if calcium intakes are adequate (3263,3264).
• Hypertension. Oral calcium seems to reduce blood pressure by a small amount. However, it is unclear if this reduction is clinically significant. Details: Many clinical trials and observational studies show that intake of calcium supplements or dietary calcium modestly reduces blood pressure in patients with or without hypertension, usually around 1-2 mmHg. Calcium seems to be more effective for certain subpopulations of patients, such as salt-sensitive people and patients with low baseline dietary calcium intake (945,972,974,976,984,1818,1819,1820,1821,6852)(13138,14406,38803,39063,39094,39221). Also, a meta-analysis of clinical research shows that calcium intake during pregnancy reduces systolic blood pressure in offspring by 1-2 mmHg (38852). However, a large-scale clinical trial in postmenopausal females shows that taking vitamin D (cholecalciferol) 400 IU daily in combination with elemental calcium 1000 mg daily does not lower blood pressure or reduce the risk of developing hypertension (16714). Additionally, a meta-analysis of 8 clinical trials shows that taking calcium in combination with vitamin D for up to 7 years has no effect on blood pressure (98861). The validity of this finding is limited by the poor methodological quality of the included studies. Some observational research suggests that calcium can reduce the risk for hypertension. Population research in females aged 45 years and older suggests that higher intake of calcium from both diet and supplement sources is linked to a lower risk of developing hypertension when compared to lower calcium intake (14265). In 2005, the US Food and Drug Administration (FDA) approved a qualified health claim stating that calcium supplements may reduce the risk of hypertension. However, the FDA has concluded that this claim is based on supporting, rather than conclusive, evidence (102367).
• Osteomalacia. Oral calcium seems to reverse osteomalacia caused by very low calcium intakes. Details: Osteomalacia is commonly caused by vitamin D deficiency; however, very low calcium intake can also lead to osteomalacia in children and adults. Calcium supplementation can reverse osteomalacia caused by calcium deficiency. Along with appropriate vitamin D supplementation, individuals at risk of osteomalacia need sufficient calcium intake (94819).
• Pre-eclampsia. Oral calcium seems to reduce the risk of pre-eclampsia in high risk pregnancies, especially if calcium intakes are low. Details: Although there is some conflicting evidence (971,38756), most clinical research shows that taking calcium orally 1-2 grams daily reduces pregnancy-related hypertension and pre-eclampsia (973,1833,8828,39043,39319,39426,96480). Calcium appears to reduce the risk of pre-eclampsia by about 50% when compared with placebo. One meta-analysis of 19 controlled trials involving over 29,000 pregnancies found that for every 19 females treated with calcium, one episode of pre-eclampsia would be avoided (96480). Calcium appears to have the greatest effect in individuals at high-risk of pre-eclampsia or with low calcium levels, and when taken at greater than or equal to 20 weeks of gestation (15029,38497,96480,99714). In 2005, the US Food and Drug Administration (FDA) approved a qualified health claim regarding the use of calcium supplements to reduce the risk of pregnancy-induced hypertension and pre-eclampsia. However, due to the limited and conflicting research available at that time, the FDA stated that this outcome was highly unlikely. Since then, large, high-quality clinical research has supported this finding. In fact, in 2016 the World Health Organization (WHO) released a recommendation to prescribe oral calcium supplementation 1.5-2 grams daily during pregnancies at high risk of pre-eclampsia if dietary calcium intakes are low, in order to prevent pre-eclampsia (97347).
• Rickets. Oral calcium seems to reverse rickets caused by very low calcium intakes. Details: Rickets is commonly caused be vitamin D deficiency; however, very low calcium intake can also lead to rickets. Calcium supplementation can reverse rickets caused by calcium deficiency (94819). A small clinical study in children with nutritional rickets shows that taking calcium 500-2000 mg daily for 24 weeks improves radiographically measured rickets caused by calcium deficiency. Rickets seems to improve more rapidly with calcium 1000 mg compared to calcium 500 mg. However, increasing the calcium dose to 2000 mg daily is not more beneficial than calcium 1000 mg daily (98904).
• Tooth retention. Oral calcium with vitamin D seems to help with tooth retention in the elderly population. Details: A clinical trial in the elderly population shows that taking calcium citrate malate 500 mg daily along with vitamin D3 (cholecalciferol) 700 IU daily orally for 3 years reduces the risk of tooth loss by about 52% when compared with placebo (8816).

POSSIBLY INEFFECTIVE

• Breast cancer. Oral calcium does not seem to be beneficial for breast cancer prevention. Details: Although some population research disagrees (15631,39041,95811,107237), most research shows that increased calcium intake is not associated with a reduced risk of breast cancer (15631,16715,98895,107236,107237). Subgroup analyses of population research suggest that calcium intake may reduce the risk of breast cancer in postmenopausal, but not pre-menopausal, adults (15631,107237). Another subgroup analysis in a large meta-analysis of population research also suggests that dietary intake may reduce estrogen receptor(ER)-negative breast cancer, but not ER-positive breast cancer (107236). However, most other research has not evaluated the effects of calcium supplementation or intake on breast cancer subtypes. The best evidence to date, from a large scale clinical trial (Women's Health Initiative), shows that taking vitamin D (cholecalciferol) 400 IU daily plus calcium 1000 mg daily for 7 years after menopause does not reduce the risk of developing invasive breast cancer at the end of the study and 5 years after the end of the intervention (16715,98895).
• Fractures. Although oral calcium prevents fractures in osteoporosis, most evidence shows that calcium does NOT prevent factures in people who do not have osteoporosis. See Osteoporosis discussion for more information on the use of calcium for this purpose. Details: The most recent and robust meta-analysis of clinical research shows that calcium supplementation with or without vitamin D is NOT associated with reduced fractures in older adults without osteoporosis (95822). A large-scale study in postmenopausal females aged 50-79 years suggests calcium 1000 mg plus vitamin D 400 IU daily for 7 years only modestly improves bone mineral density (BMD) and does not significantly reduce fracture risk. This lack of effect may have been due to low adherence to the treatment regimen. In those who were 80% adherent, the combination of calcium plus vitamin D reduced the risk of hip fracture by about 29% (14282). Also, some clinical research shows that taking calcium carbonate 1000 mg and vitamin D 400 IU for 5 years does not attenuate loss of height after menopause when compared with placebo (95810). Additional meta-analyses of clinical and observational evidence suggest that calcium supplementation is not associated with a reduced risk of vertebral or nonvertebral fractures, such as hip fractures (38589,38888,98895). Some other research has suggested that calcium in combination with vitamin D reduces fracture risk in older patients without osteoporosis (980,1836,8818,12930,12933,12952,38849,102145,107235); however, this research is confounded by a number of variables, including the presence of hormonal therapy and differing levels of fracture risk at baseline (1836,8818,95822). Conflicting findings on this topic might also be due to genetic differences in patient populations. A population analysis of the Women's Health Initiative study found that, in older females with the lowest genetic susceptibility to low bone mineral density (BMD), taking calcium with vitamin D is associated with a reduction in fracture risk. However, in females with a higher genetic susceptibility to low BMD, there is no association between supplementation and fracture risk. This might be because individuals with a lower susceptibility to low BMD are also more responsive to calcium and vitamin D supplementation (97357). As of April 2018, the U.S. Preventative Services Task Force (USPSTF) concludes that there is insufficient evidence to determine whether supplementing with vitamin D >400 IU daily along with calcium >1000 mg daily is safe and effective for preventing fractures in community dwelling adults without vitamin D deficiency, osteoporosis, or a history of fracture. USPSTF recommends against supplementing with calcium 1000 mg daily or less along with vitamin D 400 IU daily or less for preventing primary fractures in community-dwelling postmenopausal females (95695).
• Obesity. Oral calcium does not seem to improve weight loss. Details: Observational research has found that adults and children with low calcium intake are more likely to gain weight, have a higher body mass index (BMI), and be overweight or obese when compared to people with high calcium intake (12124,12125,12126,12127,14265). Additional observational research has found that increasing calcium intake is associated with weight loss in females; the results in males have been conflicting (12127,15602,15603). Despite these findings from observational research and a few small clinical studies (12128,15397,14438,98905), most clinical research has found that increased calcium intake does not increase weight loss (12052,13138,15396,15399,38985,39004,97356). The most recent meta-analysis of 20 clinical studies shows that daily dietary and supplemental calcium intake that meets the dietary reference intake (DRI) of 1000 mg or more daily does not increase weight loss in overweight individuals or patients with obesity when compared with intake below the DRI (95813). An older meta-analysis of 13 clinical trials also shows that increased dietary and supplemental calcium intake does not increase weight loss (15605).
• Overall mortality. Oral calcium does not seem to reduce overall mortality. Details: While some population research has found that calcium taken in combination with vitamin D in older females is associated with a lower risk of death (97353), most evidence shows that calcium, with or without vitamin D, has no effect on all-cause mortality (93533,97308).

INEFFECTIVE

• Cardiovascular disease (CVD). Oral calcium does not reduce the risk of developing CVD and may actually increase risk in some patients. Details: Clinical research shows that calcium does not decrease CVD risk. Several separate meta-analyses of clinical and population research involving over 50,000 patients show that taking calcium 600-1200 mg daily for up to 7 years does not reduce the risk of CVD-related outcomes, including stroke and myocardial infarction, cardiovascular death, or overall mortality (39018,91350,92994,93533,97308,98902,107231,107233). No association was found between total dietary or supplemental calcium intake with or without vitamin D and the risk of CVD or mortality (91350,93533,97308). In fact, some population and clinical research has found that when calcium is used alone or with vitamin D, there is an INCREASED risk of CVD and coronary heart disease (38077,107233). However, other clinical research disagrees (93533). One meta-analysis of high-quality randomized controlled trials shows that taking calcium for 2-7 years increases the risk of CVD and coronary heart disease by 1.1-1.2 times when compared with control. However, the majority of the included research evaluated postmenopausal females and it is unclear if this finding is applicable to other populations (107233).
• Chemotherapy-induced peripheral neuropathy. Intravenous calcium does not prevent nerve pain in patients given oxaliplatin. Oral calcium has not been evaluated for this purpose. Details: While pooled analyses of cohort studies and randomized controlled trials suggest that calcium and magnesium infusion decreases the incidence of oxaliplatin-induced neurotoxicity, a meta-analysis of only randomized controlled trials shows that the infusion has no effect in preventing neurotoxicity (90028,90029,90031). Additionally, clinical trials show that administering calcium gluconate 1 gram with magnesium sulfate 1 gram intravenously immediately before, or before and after, the administration of a single oxaliplatin cycle (90005), or over the entire 6-cycle course of oxaliplatin, does not improve symptoms of neurotoxicity when compared with placebo (96474).
• Myocardial infarction (MI). Oral calcium does not prevent MI. When taken in the absence of vitamin D, oral calcium may increase the risk of MI. Details: Population research has found that increased dietary intake of calcium is associated with a decreased risk of MI (91350). However, a 2010 meta-analysis of clinical research shows that taking calcium at a dose of at least 500 mg daily is associated with an approximate 30% INCREASE in the risk of MI in patients over the age of 40. According to this analysis, one additional case of MI will occur for every 69 patients that take calcium for 5 years (17482). A more recent meta-analysis of high-quality randomized controlled trials shows that taking calcium for 2-7 years increases the risk of MI by 1.2 times when compared with control. However, the majority of the included research studied postmenopausal females and it is unclear if this finding is applicable to other populations (107233) In contrast, other meta-analyses of clinical research have shown that taking calcium for up to 7 years is NOT associated with an increased risk of MI, including a meta-analysis that only included postmenopausal females (93533,107231). Reasons for these discrepancies are not entirely clear. It may relate to whether calcium is taken as monotherapy or in combination with vitamin D. When taken with vitamin D, which is commonly recommended, calcium supplementation does not appear to be associated with an increased risk of MI in postmenopausal females (93533). Also, the association between calcium supplementation and MI risk may be influenced by the amount of calcium consumed as part of the diet. Supplementation with calcium may be associated with an increased risk of MI in people with dietary calcium intake above 805 mg daily, but not in those with dietary calcium intake below 805 mg daily (17482)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Alcohol use disorder. It is unclear if oral calcium is beneficial for alcohol use disorder. Details: Preliminary clinical research shows that taking calcium carbonate 800 mg and vitamin D 200 IU orally daily for 14 days modestly reduces alcohol craving scores and withdrawal scores when compared with placebo in adults with alcohol dependence that are undergoing withdrawal. Taking calcium carbonate did not reduce the need for diazepam; however, the study may have been inadequately powered to detect a difference between groups (107234).
• Atherosclerosis. It is unclear if oral calcium is beneficial for atherosclerosis. Details: A population study has found that taking calcium 1.2 grams daily for 3 years has no effect on carotid intima thickness or carotid atherosclerosis incidence. A total calcium intake (dietary and supplemental) of at least 1794 mg daily in older females may be associated with a decreased risk of carotid atherosclerosis when compared with a total calcium intake below 1010 mg daily (97351).
• Autism spectrum disorder. It is unclear if oral calcium during pregnancy is beneficial for reducing the odds of autism spectrum disorder in the offspring. Details: A small observational study found that calcium supplementation during pregnancy is associated with a 52% reduced odds of an autism spectrum disorder in the offspring (98900).
• Cancer. Oral calcium alone does not seem to prevent cancer. It is unclear if oral calcium with vitamin D is beneficial for preventing cancer. Details: Taking calcium alone does not seem to significantly reduce the risk of cancer (12118,15629). The role of calcium in cancer prevention when taken along with vitamin D is controversial, as conflicting results exist. One clinical trial shows that healthy postmenopausal females who take supplemental calcium 1400-1500 mg daily plus vitamin D3 (cholecalciferol) 1100 IU daily have a 60% lower relative risk for developing cancer of any type. Approximately 25 postmenopausal females would need to take this combination for 4 years to prevent one occurrence of cancer (15629). However, a more recent clinical study shows that healthy postmenopausal females who take supplemental calcium 1500 mg daily plus vitamin D3 (cholecalciferol) 2000 IU daily do not have a reduced risk of cancer at 4 years (93943). Reasons for the disparate results are not entirely clear. The discrepancies do not appear to be related to baseline vitamin D levels or different study populations. It is possible that, given the 10-year time lapse between the two publications, the discrepancies result from differences in cancer detection capability. Also, since cancer risk was a secondary outcome measure in the earlier study and a primary outcome measure in the more recent study, it is possible that the discrepancies result from differences in statistical methodologies. The effect of vitamin D and calcium on cancer risk in males and younger patients is not known. There is also interest in using calcium for reducing the risk of hematological malignancies. An analysis of the Women's Health Initiative study shows that taking calcium 1000 mg daily in combination with vitamin D3 400 IU for up to 10 years is associated with a 20% reduction in the risk of hematologic malignancies when compared with placebo. However, no effect on hematologic malignancy related mortality was seen (97354).
• Depression. It is unclear if oral calcium is beneficial for depression prevention. Details: Population research has found no association between a higher dietary intake of calcium and the risk of depression when compared with a lower dietary intake of calcium (96480).
• Diabetes. It is unclear if oral calcium is beneficial for type 2 diabetes prevention. Details: Some population research has found that a higher intake of calcium from diet or supplements, alone or in combination with vitamin D, is associated with a lower risk of developing type 2 diabetes when compared with lower calcium intake (14265,16713,96473). However, population research is often limited by confounding variables. For example, one analysis found that any beneficial effect might be influenced by concomitant magnesium intake (96473). Furthermore, other population research has found that serum calcium levels higher than 9.6 mg/dL are associated with greater risk of developing diabetes in Chinese adults with osteoporosis. This study is limited because it was not determined whether increased serum calcium was due to increased calcium intake or another factor such as parathyroid function (95815).
• Dysmenorrhea. It is unclear if oral calcium is beneficial for reducing pain associated with dysmenorrhea. Details: Clinical research shows that taking calcium carbonate 1000 mg with vitamin D 5000 IU daily for three menstrual cycles does not reduce pain when compared with placebo in patients with primary dysmenorrhea (95821). However, calcium carbonate 1000 mg taken alone seems to reduce pain when compared with placebo.
• Endometrial cancer. It is unclear if oral calcium is beneficial for endometrial cancer prevention. Details: A meta-analysis of population research suggests that calcium supplements may reduce the risk of endometrial cancer, but dietary calcium does not seem to have any effect (38893).
• Fall prevention. It is unclear if oral calcium with vitamin D is beneficial for preventing falls. Details: Research suggests that calcium in combination with vitamin D, but not calcium alone, might prevent falls by decreasing body sway and normalizing systolic blood pressure (6362,11939,39038). Some experts think the combination of calcium and vitamin D may be important (11916). Preliminary clinical research in adults residing in a health care facility shows that taking vitamin D supplements while increasing dietary calcium and protein for 2 years reduces falls by 11% when compared with standard diets. Intervention diets were supplemented with milk, yogurt, and cheese to provide calcium 1142 mg and protein 69 grams daily (107235). There might also be different effects in females compared to males. In one study, females aged 65 years or older who took vitamin D 700 IU plus calcium citrate 500 mg daily over a 3-year period had a 46% lower risk of falling. However, this combination did not decrease falls in males (14291).
• Fluorosis. Oral calcium has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Taking calcium orally, in combination with ascorbic acid (vitamin C) and vitamin D, seems to be effective for reducing excessive fluoride levels in children and improving symptoms of fluorosis in children aged 6-12 years (990).
• Heart failure. It is unclear if oral calcium in combination with vitamin D is beneficial for preventing heart failure. Details: Based on a secondary analysis of a large-scale clinical trial (Women's Health Initiative), taking calcium 1000 mg with vitamin D 400 IU daily does not reduce the risk of heart failure in the overall population or in individuals at high risk. However, in a subgroup of postmenopausal females without risk factors for heart failure, calcium and vitamin D supplementation might reduce the risk of developing heart failure by about 37% (97307).
• Hypercholesterolemia. It is unclear if oral calcium is beneficial for hypercholesterolemia. Details: Some evidence shows that taking calcium carbonate 400 mg three times daily reduces low-density lipoprotein (LDL) cholesterol levels by 4% and increases high-density lipoprotein (HDL) cholesterol levels by 4% after 6 weeks of treatment when used in combination with a low-fat diet (American Heart Association Step 1) (2557). In contrast, a study in females with dyslipidemia shows that taking calcium 800 mg daily for 2 years might INCREASE total cholesterol levels by about 12 mg/dL when compared with placebo. This same study showed an association between calcium supplementation and an increase in total cholesterol levels and carotid intimal thickness in postmenopausal females, but not premenopausal females (97350). A recent meta-analysis of randomized controlled trials which included both healthy patients and patients with dyslipidemia shows that taking calcium 500-2000 mg daily and vitamin D 200-7142 IU daily modestly improves HDL cholesterol and triglyceride levels, but not LDL cholesterol levels, when compared with placebo. Subgroup analyses suggest that calcium and vitamin D supplementation is more effective in patients with dyslipidemia at baseline. It is unclear if this effect is due to calcium, vitamin D, or the combination (107227). However, other research shows that taking a specific supplement containing calcium 600 mg plus vitamin D 200 IU (Caltrate 600 D, Wyeth Consumer Healthcare Inc.) twice daily in combination with calorie restriction does not reduce total or LDL cholesterol levels when compared with placebo (15601).
• Lead toxicity. It is unclear if oral calcium is beneficial for reducing blood levels of lead. Details: Lead is mobilized along with calcium from bone during pregnancy and lactation, resulting in increased serum concentrations of lead. One clinical study suggests that calcium supplementation does not significantly decrease these elevated lead concentrations (1586). However, another clinical study suggests that taking calcium reduces blood lead levels by 11% when compared with placebo, with greatest effects observed in those with high baseline levels of lead (38957).
• Lyme disease. Although there is interest in using oral calcium for Lyme disease, there is insufficient reliable information about the clinical effects of calcium for this condition.
• Metabolic syndrome. It is unclear if oral calcium alone or with vitamin D is beneficial for metabolic syndrome prevention. Details: Population research has found that a higher intake of calcium from diet and supplements alone, or in combination with vitamin D, is associated with a lower risk of developing metabolic syndrome when compared with lower calcium intake (14265,16713).
• Nephrotic syndrome. It is unclear if oral calcium with vitamin D is beneficial for preventing nephrotic syndrome. Details: Clinical research shows that taking calcium 500-1000 mg daily for 3 months in combination with vitamin D3 60,000 IU daily or weekly for 4 weeks has no effect on bone mineral density or the risk of relapse in children with steroid-sensitive nephrotic syndrome (97355).
• Nonmelanoma skin cancer. It is unclear if oral calcium is beneficial for preventing keratinocyte carcinomas. Details: In middle aged and older adults recently diagnosed with a colorectal adenoma, clinical research shows that taking calcium 1200 mg daily as calcium carbonate for 3-5 years does not reduce the incidence of keratinocyte cancer when compared with placebo over a median of 8 years. A sub-group analysis shows that taking calcium alone or with vitamin D3 1000 IU daily reduced the risk of invasive cutaneous squamous cell carcinoma by a moderate amount, but had no effect on the risk of basal cell carcinoma (104622).
• Oral mucositis. When used in combination with fluoride treatments, a calcium phosphate mouth rinse seems to prevent and reduce mucositis-related pain in patients undergoing hematopoietic stem cell transplantation (HSCT). Details: A small clinical study in patients undergoing HSCT shows that using a particular mouth rinse (Caphosol, EUSA Pharma) containing calcium phosphate, in combination with fluoride treatments, reduces days of mucositis, the duration of pain, and the dose and days of morphine used when compared with placebo and fluoride treatment (38611).
• Ovarian cancer. It is unclear if oral calcium is beneficial for ovarian cancer prevention. Details: An older meta-analysis of 12 cohort studies found that dietary calcium intake is not associated with a reduced risk of ovarian cancer (38792). However, a more recent pooled analysis of 15 cohort and case-control studies has found that the highest intake of dietary or dairy calcium is associated with a 20% lower risk of ovarian cancer when compared to the lowest intake (97349).
• Postpartum depression. It is unclear if oral calcium is beneficial for reducing postpartum depression risk. Details: Preliminary clinical research shows that taking calcium 2 grams daily beginning at 11-21 weeks gestation reduces depression at 12 weeks postpartum when compared with placebo. However, no benefit is seen at 6 weeks postpartum (39447).
• Pregnancy-related leg cramps. It is unclear if oral calcium is beneficial for preventing leg cramps during pregnancy. Details: A small clinical study shows that taking calcium 1 gram twice daily (as a mixture of salts) for 2 weeks can reduce pregnancy-related leg cramps during the second half of pregnancy when compared with no treatment (2567).
• Prostate cancer. It is unclear if oral calcium is beneficial for prostate cancer prevention. Details: Some clinical research shows that taking calcium 1200 mg daily might decrease the risk of developing prostate cancer (14133). However, some epidemiological research suggests that consuming very high doses of calcium, over 2000 mg daily, might actually increase the risk of developing prostate cancer (14134). Some epidemiological research also suggests that doses greater than 1500 mg daily increase the risk of poorly differentiated, clinically advanced, and fatal prostate cancer (14132). Consumption of dairy products has also been weakly linked to a modest increase in risk of prostate cancer (98894). However, contradictory research suggests that there is no association between dietary intake of calcium and overall risk of prostate cancer (14131,14132,104630).
• Stroke. It is unclear if oral calcium is beneficial for stroke prevention. Details: Some population research has found that increasing dietary calcium intake is associated with a decreased risk of ischemic stroke (4822,38678). However, other population research has found that increasing dietary calcium intake is not associated with a decreased risk of stroke (91350). One meta-analysis of high-quality randomized controlled trials shows that taking calcium for 2-7 years does not affect the risk of stroke when compared with control. However, the majority of the included research evaluated postmenopausal females, and it is unclear if this finding is applicable to other populations (107233).
• Vertigo. Oral calcium with vitamin D might reduce positional vertigo; the effect of calcium when used alone is unclear. Details: A large clinical study in adults with recurrent benign paroxysmal positional vertigo shows that taking calcium 500 mg and vitamin D 400 IU twice daily for one year reduces annual recurrence of vertigo by 27% when compared with no treatment. The number needed to treat to prevent vertigo was 3.7 (103681). It is unclear if this benefit is due to vitamin D, calcium, or the combination. More evidence is needed to rate calcium for these uses.

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LIKELY SAFE ...when used orally with appropriate fluid intake (93216). Blond psyllium preparations have been safely used in doses up to 20 grams per day for up to 6 months (1376,2324,2327,6261,6262,8060,8061,8066,8423,9422) (10095,13102,22961,22962,22963,22964,22966,54260,22968,22969) (22970,22972,22973,22976,22977,22978,22979,22980,22981,22986) (22987,22988,22989,22990,22992,22993,22994,22995,22996,22998) (23402,23403,23404,23405,92198,106859). The U.S. Food and Drug Administration (FDA) requires over-the-counter medicines that contain dry or incompletely hydrated psyllium to carry a warning that they should be taken with at a least a full glass of liquid to reduce the risk of choking. This labeling also applies to foods containing psyllium that are marketed with a health claim regarding coronary heart disease (93217,93218).

POSSIBLY SAFE ...when used in eye drops. Blond psyllium mucilage has been used with apparent safety in eye drops four times daily for 6 weeks (105274). There is insufficient reliable information available about the safety of blond psyllium when used topically.

LIKELY UNSAFE ...when used orally without adequate fluid intake due to the risk for choking and gastrointestinal obstruction (93218). ...when granular dosage forms containing blond psyllium are used as over the counter (OTC) laxatives. The U.S. Food and Drug Administration (FDA) states that these granular dosage forms are not generally recognized as safe and effective as OTC laxatives due to an increased risk of choking and gastrointestinal obstruction (93219).

CHILDREN: POSSIBLY SAFE
when used orally and appropriately, short-term. Blond psyllium husk has been used with apparent safety in doses up to 12 grams daily for 4 weeks (110763).

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally and appropriately (272).

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LIKELY SAFE ...when used orally or intravenously and appropriately. Calcium is safe when used in appropriate doses (7555,12928,12946,95817). However, excessive doses should be avoided. The Institute of Medicine sets the daily tolerable upper intake level (UL) for calcium according to age as follows: Age 0-6 months, 1000 mg; 6-12 months, 1500 mg; 1-8 years, 2500 mg; 9-18 years, 3000 mg; 19-50 years, 2500 mg; 51+ years, 2000 mg (17506). Doses over these levels can increase the risk of side effects such as kidney stone, hypercalciuria, hypercalcemia, and milk-alkali syndrome. There has also been concern that calcium intake may be associated with an increased risk of cardiovascular disease (CVD) and coronary heart disease (CHD), including myocardial infarction (MI). Some clinical research suggests that calcium intake, often in amounts over the recommended daily intake level of 1000-1300 mg daily for adults, is associated with an increased risk of CVD, CHD, and MI (16118,17482,91350,107233). However, these studies, particularly meta-analyses, have been criticized for excluding trials in which calcium was administered with vitamin D (94137). Many of these trials also only included postmenopausal females. Other analyses report conflicting results, and have not shown that calcium intake affects the risk of CVD, CHD, or MI (92994,93533,97308,107231). Advise patients not to consume more than the recommended daily intake of 1000-1200 mg per day and to consider total calcium intake from both dietary and supplemental sources (17484). Also, advise patients taking calcium supplements to take calcium along with vitamin D (93533).

POSSIBLY UNSAFE ...when used orally in excessive doses. The National Academy of Medicine sets the daily tolerable upper intake level (UL) for calcium according to age as follows: 19-50 years, 2500 mg; 51 years and older, 2000 mg (17506). Doses over these levels can increase the risk of side effects such as kidney stones, hypercalciuria, hypercalcemia, and milk-alkali syndrome. There has also been concern that calcium intake may be associated with an increased risk of cardiovascular disease (CVD) and coronary heart disease (CHD), including myocardial infarction (MI). Some clinical research suggests that calcium intake, often in amounts over the recommended daily intake level of 1000-1300 mg daily for adults, is associated with an increased risk of CVD, CHD, and MI (16118,17482,91350,107233). However, these studies, particularly meta-analyses, have been criticized for excluding trials in which calcium was administered with vitamin D (94137). Many of these trials also only included postmenopausal females. Other analyses report conflicting results, and have not shown that calcium intake affects the risk of CVD, CHD, or MI (92994,93533,97308,107231). Advise patients to not consume more than the recommended daily intake of 1000-1200 mg per day and to consider total calcium intake from both dietary and supplemental sources (17484). Also, advise patients taking calcium supplements to take calcium along with vitamin D (93533).

CHILDREN: LIKELY SAFE
when used orally and appropriately. Calcium is safe when used in appropriate doses (17506).

CHILDREN: POSSIBLY UNSAFE
when used orally in excessive doses. The Institute of Medicine sets the daily tolerable upper intake level (UL) for calcium according to age as follows: 0-6 months, 1000 mg; 6-12 months, 1500 mg; 1-8 years, 2500 mg; 9-18 years, 3000 mg (17506). Doses over these levels can increase the risk of side effects such as kidney stones, hypercalciuria, hypercalcemia, and milk-alkali syndrome.

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally and appropriately (945,1586,3263,3264,17506). The World Health Organization (WHO) recommends prescribing oral calcium supplementation 1.5-2 grams daily during pregnancy to those with low dietary calcium intake to prevent pre-eclampsia (97347).

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally in excessive doses. The Institute of Medicine sets the same daily tolerable upper intake level (UL) for calcium according to age independent of pregnancy status: 9-18 years, 3000 mg; 19-50 years, 2500 mg (17506). Doses over these amounts might increase the risk of neonatal hypocalcemia-induced seizures possibly caused by transient neonatal hypoparathyroidism in the setting of excessive calcium supplementation during pregnancy, especially during the third trimester. Neonatal hypocalcemia is a risk factor for neonatal seizures (97345).

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CARBAMAZEPINE (Tegretol) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, blond psyllium might reduce the effects of carbamazepine and increase the risk for convulsions.  Details Blond psyllium might reduce carbamazepine absorption and serum levels (539,92194). A preliminary study using blond psyllium reported decreased carbamazepine bioavailability due to binding of the drug to psyllium, as well as reduction of available fluid in the gut for dissolution of the drug (539).

DIGOXIN (Lanoxin) Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = B Theoretically, taking blond psyllium at the same time as digoxin might reduce digoxin absorption.  Details Psyllium might bind digoxin in the gut (12). However, some clinical evidence suggests that psyllium does not impact digoxin absorption (10098).

ETHINYL ESTRADIOL Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, taking blond psyllium at the same time as ethinyl estradiol might alter levels of estradiol.  Details Concurrent use of blond psyllium with ethinyl estradiol results in a slight increase in the extent of ethinyl estradiol absorption and a slower rate of absorption. However, this is unlikely to be clinically significant (12421).

LITHIUM Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, taking blond psyllium at the same time as lithium might reduce lithium absorption.  Details The fiber in blond psyllium might decrease the absorption of lithium. Some case reports describe a reduction in plasma lithium levels with concomitant administration of blond psyllium. This was reversed when psyllium was stopped (540,92194).

METFORMIN (Glucophage) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, blond psyllium might increase the therapeutic and adverse effects of metformin.  Details Concurrent use of blond psyllium with metformin slows and increases metformin absorption (99433). To avoid changes in absorption, take psyllium 30-60 minutes after metformin.

OLANZAPINE (Zyprexa) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking blond psyllium at the same time as olanzapine might reduce olanzapine absorption.  Details The fiber in blond psyllium might decrease the absorption of olanzapine. A single case report describes a reduction in the effectiveness of olanzapine when it was taken concomitantly with an unspecified type of psyllium 3 grams orally twice daily. This effect was reversed when psyllium was stopped (106858).

ORAL DRUGS Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.  Details Psyllium seems to have variable effects on drug absorption. To avoid changes in absorption, take psyllium 30-60 minutes after oral medications. Animal research shows that blond psyllium delays and increases the absorption of metformin and ethinyl estradiol (12421,99433). Conversely, case reports and animal research suggest that blond psyllium might reduce absorption of lithium, digoxin, olanzapine, and carbamazepine (12,18,272,93214,106858). Finally, some pharmacokinetic studies show that psyllium does not affect the absorption of levothyroxine or warfarin (12420,103940).

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ALUMINUM Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Calcium citrate might increase aluminum absorption and toxicity. Other types of calcium do not increase aluminum absorption.  Details Calcium citrate can increase the absorption of aluminum when taken with aluminum hydroxide. The increase in aluminum levels may become toxic, particularly in individuals with kidney disease (21631). However, the effect of calcium citrate on aluminum absorption is due to the citrate anion rather than calcium cation. Calcium acetate does not appear to increase aluminum absorption (93006).

BISPHOSPHONATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = C Calcium reduces the absorption of bisphosphonates.  Details Advise patients to take bisphosphonates at least 30 minutes before calcium, but preferably at a different time of day. Calcium supplements decrease absorption of bisphosphonates (12937).

CALCIPOTRIENE (Dovonex) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Taking calcipotriene with calcium might increase the risk for hypercalcemia.  Details Calcipotriene is a vitamin D analog used topically for psoriasis. It can be absorbed in sufficient amounts to cause systemic effects, including hypercalcemia (12938). Theoretically, combining calcipotriene with calcium supplements might increase the risk of hypercalcemia.

CALCIUM CHANNEL BLOCKERS Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Intravenous calcium may decrease the effects of calcium channel blockers; oral calcium is unlikely to have this effect.  Details Intravenous calcium is used to decrease the effects of calcium channel blockers in the management of overdose. Intravenous calcium gluconate has been used before intravenous verapamil (Isoptin) to prevent or reduce the hypotensive effects without affecting the antiarrhythmic effects (6124). But there is no evidence that dietary or supplemental calcium when taken orally interacts with calcium channel blockers (12939,12947).

CEFTRIAXONE (Rocephin) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = D Co-administration of intravenous calcium and ceftriaxone can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys.  Details Avoid administering intravenous calcium in any form, such as parenteral nutrition or Lactated Ringers, within 48 hours of intravenous ceftriaxone. Case reports in neonates show that administering intravenous ceftriaxone and calcium can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys. In several cases, neonates have died as a result of this interaction (15794,21632). So far there are no reports in adults; however, there is still concern that this interaction might occur in adults.

DIGOXIN (Lanoxin) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Using intravenous calcium with digoxin might increase the risk of fatal cardiac arrhythmias.  Details Hypercalcemia increases the risk of fatal cardiac arrhythmias with digoxin (12940). However, one retrospective analysis of clinical data suggests that intravenous calcium does not increase the risk of dysrhythmias or mortality in patients receiving digoxin (38960).

DILTIAZEM (Cardizem, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, calcium may reduce the therapeutic effects of diltiazem.  Details Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation (10574). Theoretically, calcium might increase this risk of hypercalcemia and reduce the effectiveness of diltiazem.

DOLUTEGRAVIR (Tivicay) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Calcium seems to reduce levels of dolutegravir.  Details Advise patients to take dolutegravir either 2 hours before or 6 hours after taking calcium supplements. Pharmacokinetic research suggests that taking calcium carbonate 1200 mg concomitantly with dolutegravir 50 mg reduces plasma levels of dolutegravir by almost 40%. Calcium appears to decrease levels of dolutegravir through chelation (93578).

ELVITEGRAVIR (Vitekta) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Calcium seems to reduce levels of elvitegravir.  Details Advise patients to take elvitegravir either 2 hours before or 2 hours after taking calcium supplements. Pharmacokinetic research suggests that taking calcium along with elvitegravir can reduce blood levels of elvitegravir through chelation (94166).

LEVOTHYROXINE (Synthroid, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Calcium seems to reduce the absorption and effectiveness of levothyroxine.  Details Advise patients to take levothyroxine and calcium supplements at least 4 hours apart. Calcium reduces levothyroxine absorption, probably by forming insoluble complexes (5082). Calcium carbonate supplements reduce effectiveness of levothyroxine in patients with hypothyroidism (5081,5082,6137).

LITHIUM Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, concomitant use of calcium and lithium may increase this risk of hypercalcemia.  Details Clinical research suggests that long-term use of lithium may cause hypercalcemia in 10% to 60% of patients (38953). Theoretically, concomitant use of lithium and calcium supplements may further increase this risk.

QUINOLONE ANTIBIOTICS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Calcium seems to reduce the absorption of quinolone antibiotics.  Details Advise patients to take oral quinolones at least 2 hours before or 4-6 hours after calcium supplements or calcium-fortified foods. Taking calcium at the same time as oral quinolones can reduce quinolone absorption. Calcium binds to quinolones in the gut (4412,10339,21638,38570).

RALTEGRAVIR (Isentress) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Calcium may reduce levels of raltegravir.  Details Pharmacokinetic research shows that taking a single dose of calcium carbonate 3000 mg along with raltegravir 400 mg twice daily modestly decreases the mean area under the curve of raltegravir, but the decrease does not necessitate a dose adjustment of raltegravir (94164). However, a case of elevated HIV-1 RNA levels and documented resistance to raltegravir has been reported for a patient taking calcium carbonate 1 gram three times daily plus vitamin D3 (cholecalciferol) 400 IU three times daily in combination with raltegravir 400 mg twice daily for 11 months. It is thought that calcium reduced raltegravir levels by chelation, leading to treatment failure (94165).

SOTALOL (Betapace) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Calcium seems to reduce the absorption of sotalol.  Details Advise patients to separate doses by at least 2 hours before or 4-6 hours after calcium. Calcium appears to reduce the absorption of sotalol, probably by forming insoluble complexes (10018).

TETRACYCLINE ANTIBIOTICS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = C Calcium seems to reduce the absorption of tetracycline antibiotics.  Details Advise patients to take oral tetracyclines at least 2 hours before, or 4-6 hours after calcium supplements. Taking calcium at the same time as oral tetracyclines can reduce tetracycline absorption. Calcium binds to tetracyclines in the gut (1843).

THIAZIDE DIURETICS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = C Taking calcium along with thiazides might increase the risk of hypercalcemia and renal failure.  Details Thiazides reduce calcium excretion by the kidneys (1902). Using thiazides along with moderately large amounts of calcium carbonate increases the risk of milk-alkali syndrome (hypercalcemia, metabolic alkalosis, renal failure). Patients may need to have their serum calcium levels and/or parathyroid function monitored regularly.

VERAPAMIL (Calan, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, calcium may reduce the therapeutic effects of verapamil.  Details Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation (10574). Theoretically, use of calcium supplements may increase this risk of hypercalcemia and reduce the effectiveness of verapamil.

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General ...Orally, blond psyllium is generally well tolerated. When used as eye drops, blond psyllium seems to be well tolerated.
Most Common Adverse Effects:
Oral: Abdominal pain, constipation, diarrhea, dyspepsia, flatulence, and nausea.
Serious Adverse Effects (Rare):
Oral: Bowel obstruction, esophageal obstruction.

Gastrointestinal ...Orally, blond psyllium can cause transient flatulence, abdominal pain, diarrhea, constipation, dyspepsia, and nausea (1376). Starting with a low dose and slowly titrating to the desired dose can often minimize gastrointestinal side effects. There is some concern that blond psyllium can cause esophageal or bowel obstruction when consumed without water or in patients with swallowing disorders (604,8080,8081,110760). Tell patients to consume plenty of water when taking blond psyllium. Suggest at least 240 mL of fluid for every 3.5-5 grams of seed husk or 7 grams of seed (1376,8080,8081).

Musculoskeletal ...Orally, backache has been reported with the use of psyllium (1376).

Neurologic/CNS ...Orally, headache has been reported with the use of psyllium (1376).

Ocular/Otic ...Ophthalmically, blurred vision or burning haven been reported rarely in patients using eye drops containing blond psyllium mucilage (105274).

Pulmonary/Respiratory ...Orally, rhinitis, increased cough, and sinusitis have been reported with the use of psyllium (1376).

Other ...Some patients can have an allergic response to blond psyllium. Allergy symptoms include allergic rhinitis, sneezing, conjunctivitis, urticarial rash, itching, flushing, and dyspnea. More serious symptoms include wheezing, facial and body swelling, chest congestion, chest and throat tightness, cough, diarrhea, hypotension, loss of consciousness, and anaphylactic shock. Occupational exposure or repeated ingestion of psyllium can cause sensitization, which can lead to serious allergic reactions (2328,2329,2330,8079,9246,92193). Severe allergic reactions may occur after eating a small quantity of cereal that contains blond psyllium. At least one cereal (Heartwise, Kellogg Co.) has increased the purity of the psyllium it contains, which has decreased the incidence of allergic reactions (9244). A warning of the potential for allergic reactions is on the label of all cereals that contain psyllium (9247). Patients hypersensitive to psyllium usually have marked eosinophilia and an elevated psyllium-specific IgE antibody serum level (2328,2329,92193).
There is concern that individuals allergic to pollen from English plantain weed (Plantain lanceolate) might also react to psyllium husk dust; however, it appears that there is little cross-allergenicity between these plants and is probably mild and of no clinical significance (8057,9244,92193).
Blond psyllium has a tendency to plug feeding tubes. This can be avoided if blond psyllium is mixed with water and pushed through the feeding tube in less than 5 minutes (8423).

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General ...Orally and intravenously, calcium is well-tolerated when used appropriately.
Most Common Adverse Effects:
Orally: Belching, constipation, diarrhea, flatulence, and stomach upset.
Serious Adverse Effects (Rare):
Orally: Case reports have raised concerns about calciphylaxis and kidney stones.

Cardiovascular ...There has been concern that calcium intake may be associated with an increased risk of cardiovascular disease (CVD) and coronary heart disease (CHD), including myocardial infarction (MI). Some clinical research suggests that calcium intake, often in amounts over the recommended daily intake level of 1000-1300 mg daily for adults, is associated with an increased risk of CVD, CHD, and MI (16118,17482,91350,107233). However, these results, particularly meta-analyses, have been criticized for excluding trials in which calcium was administered with vitamin D (94137). Many of these trials also only included postmenopausal females. Other analyses report conflicting results, and have not shown that calcium intake affects the risk of CVD, CHD, or MI (92994,93533,97308,107231). Reasons for these discrepancies are not entirely clear. It may relate to whether calcium is taken as monotherapy or in combination with vitamin D. When taken with vitamin D, which is commonly recommended, calcium supplementation does not appear to be associated with an increased risk of CVD, CHD, or MI (93533,107231). Also, the association between calcium supplementation and CVD, CHD, or MI risk may be influenced by the amount of calcium consumed as part of the diet. Supplementation with calcium may be associated with an increased risk of MI in people with dietary calcium intake above 805 mg daily, but not in those with dietary calcium intake below 805 mg daily (17482). To minimize the possible risk of CVD, CHD, or MI, advise patients not to consume more than the recommended daily intake of 1000-1200 mg and to consider total calcium intake from both dietary and supplemental sources (17484). While dietary intake of calcium is preferred over supplemental intake, advise patients who require calcium supplements to take calcium along with vitamin D, as this combination does not appear to be associated with an increased risk of MI (93533).
Rarely, calcium intake can increase the risk of calciphylaxis, which usually occurs in patients with kidney failure. Calciphylaxis is the deposition of calcium phosphate in arterioles, which causes skin ulcers and skin necrosis. In a case report, a 64-year-old female with a history of neck fracture, sepsis, and ischemic colitis presented with painful leg ulcers due to calciphylaxis. She discontinued calcium and vitamin D supplementation and was treated with sodium thiosulfate and supportive care (95816).

Gastrointestinal ...Orally, calcium can cause belching, flatulence, nausea, gastrointestinal discomfort, and diarrhea (1824,1843,12950,38803). Although constipation is frequently cited as an adverse effect of calcium, there is no scientific substantiation of this side effect (1824,1843,1844,1845,12950,38978). Calcium carbonate has been reported to cause acid rebound, but this is controversial (12935,12936).

Oncologic ...There is some concern that very high doses of calcium might increase the risk of prostate cancer. Some epidemiological evidence suggests that consuming over 2000 mg/day of dietary calcium might increase the risk for prostate cancer (4825,12949). Additional research suggests that calcium intake over 1500 mg/day might increase the risk of advanced prostate cancer and prostate cancer mortality (14132). Consumption of dairy products has also been weakly linked to a small increase in prostate cancer risk (98894). However, contradictory research suggests no association between dietary intake of calcium and overall prostate cancer risk (14131,14132,104630). More evidence is needed to determine the effect of calcium, if any, on prostate cancer risk.

Renal ...Kidney stones have been reported in individuals taking calcium carbonate 1500 mg daily in combination with vitamin D 2000 IU daily for 4 years (93943).

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