Red Marine Algae [Discontinued] by Swanson GreenFoods Formulas

POSSIBLY INEFFECTIVE

• Human papillomavirus (HPV). Topical carrageenan gel does not seem to reduce the risk of anal HPV in males who have sex with males. Details: A clinical study in adult males who have sex with males shows that applying 15 mL of carrageenan 1.4% gel to the anus, condom, or partners' penis prior to receptive anal intercourse does not decrease the rate of anal HPV when compared with placebo, regardless of HPV strain, HPV vaccination status, or HIV status. Although patients were enrolled for an intended duration of 1 year, the study was terminated early due to a lack of observed benefit and potential safety concerns, resulting in a median follow-up of 8 months. A total of 60% of patients in the treatment group reported adverse effects, compared with 40% of patients in the placebo group (107851). Additionally, the prevalence of HPV at baseline was 61%, which may have reduced the study's ability to identify an effect.

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Common cold. Evidence on the use of intranasal iota-carrageenan for improving symptoms of the common cold is conflicting. Details: A small clinical study in patients with early symptoms of the common cold shows that spraying a saline solution containing iota-carrageenan 0.12% into the nose three times daily for 4 days seems to reduce total symptoms during days 2-4 when compared with using a plain saline spray. However, in a larger clinical trial using the same methods, there were no differences between placebo and treatment groups. Furthermore, neither study noted an improvement in total cold symptoms over 7-10 days (99449,99450). In children with the common cold, spraying a saline solution containing iota-carrageenan 0.12% seemed to be no better for improving cold symptoms than using plain saline spray (99451). Some research suggests that carrageenan might benefit patients with a confirmed viral infection. In a clinical study in patients with symptoms of a common cold and a laboratory-confirmed viral infection, using a specific nasal spray (Coldamaris) containing carrageenan 0.12% three times daily for 7 days reduced symptom duration by about 2 days when compared with using a saline nasal spray. However, there was no difference in disease duration when all patients were considered, regardless of viral infection status (99452). Furthermore, the validity of this study is limited by the changing definitions for disease duration and primary outcome over the course of the study.
• Coronavirus disease 2019 (COVID-19). There is limited evidence on the intranasal use of iota-carrageenan for the prevention of COVID-19. Details: A clinical study in healthcare professionals working with patients hospitalized for COVID-19 shows that using a nasal spray containing iota-carrageenan 0.17% as 1 puff in each nostril 4 times daily (providing 1 mg daily) for 21 days decreases the absolute rate of confirmed, symptomatic COVID-19 to 1%, compared with 5% of patients in the placebo group. This suggests that 25 people would need to use this nasal spray to prevent one infection (107852). The validity of this study is limited due to the lack of baseline viral testing and short duration; additionally, asymptomatic COVID-19 infections may be underreported due to study design.
• Cough. Although there is interest in using oral carrageenan for cough, there is insufficient reliable information about the clinical effects of carrageenan for this condition. More evidence is needed to rate the effectiveness of carrageenan for these uses.

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LIKELY SAFE ...when undegraded carrageenan is used orally in the amounts found in foods (11). Carrageenan has Generally Recognized as Safe (GRAS) status in the US (4912,102538).

POSSIBLY SAFE ...when used intranasally, short-term. Saline solution containing iota-carrageenan 0.12% has been sprayed into the nose with apparent safety three times daily for up to 7 days (99449,99450,99451,99452,99466). Also, saline solution containing iota-carrageenan 0.17% has been sprayed into both nostrils with apparent safety four times daily (providing 1 mg daily) for up to 21 days (107852).

POSSIBLY UNSAFE ...when the degraded form, called poligeenan, is used orally. Poligeenan contains a lower molecular weight product that is partially absorbed. There is concern about the safety of this form because it has been linked to colonic lesions, neoplasms, and bleeding in animals (40065,40047). Due to public concern that commercial carrageenan contains poligeenan or can be degraded to poligeenan in the stomach, the United States Food and Drug Administration (FDA) reevaluated the safety of carrageenan and reaffirmed its status as GRAS in 2012 (99466). Carrageenan that is not degraded has an average molecular weight of 453-652 kDA, while degraded carrageenan is usually 20-30 kDA. In order to limit potential safety concerns, the European Commission Scientific Committee on Food advises that the total weight of any carrageenan food additives contain no more than 5% of a molecular weight below 50 kDa (99901). There is insufficient reliable information available about the safety of carrageenan when used topically.

PREGNANCY AND LACTATION: LIKELY SAFE
when used in food amounts (11). There is insufficient reliable information available about the safety of using larger amounts; avoid using.

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ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, carrageenan may increase the risk of bleeding in patients taking anticoagulant or antiplatelet drugs.  Details Laboratory research suggests that carrageenan has anticoagulant effects (6002). However, this has not been reported in humans.

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General ...Orally, carrageenan is well tolerated in amounts found in foods. Intranasally, carrageenan seems to be well tolerated.
Most Common Adverse Effects: None known.

Dermatologic ...Topically, when carrageenan gel was applied to the penis or anus prior to anal intercourse in one clinical study, it was reported to cause discomfort or adverse reactions in 59% of males, compared with 44% of those using placebo (107851).

Genitourinary ...Intravaginally, carrageenan gel has been associated with mild vaginal itching and burning, a vaginal abrasion, bladder fullness, and urinary hesitancy. However, it is unclear if carrageenan was the causal factor of these symptoms (40044,40068).

Hematologic ...In one clinical study in males, carrageenan gel applied topically to the penis and anus prior to anal intercourse was reported to cause rectal bleeding that was not directly related to anal intercourse in 8% of patients, compared with 0% of patients using placebo (107851).

Oncologic ...Observational research has found that increased consumption of carrageenan is associated with an increase in breast cancer incidence (40046).

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