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April 2013

Garlic May Help Reduce Long-Term Diabetes Complications

Garlic may help control high levels of C-reactive protein and adenosine deaminase in obese people with diabetes, according to a study.

C-reactive protein is a marker of inflammation, while adenosine deaminase is an enzyme that is involved in metabolism. Previous research has linked high C-reactive protein and adenosine deaminase levels to long-term complications in people with uncontrolled diabetes.

Researchers set out to determine if garlic may help control levels of C-reactive protein and adenosine deaminase in obese people with type 2 diabetes. They enrolled 60 subjects who were given either metformin tablets with garlic capsules or metformin tablets alone after meals. They measured the participants' blood glucose, adenosine deaminase levels, and cholesterol at the beginning of the study, then conducted a 12-week follow-up to continue monitoring these factors.

The results suggested that both metformin with garlic and metformin alone helped significantly reduce blood sugar. However, a drop in total cholesterol, low density lipoprotein (LDL or "bad") cholesterol, and triglyceride appeared to be more significant in the group given metformin and garlic. The metformin and garlic group also had a greater decrease in C-reactive protein and adenosine deaminase levels, compared to the subjects given only metformin.

The research team concluded that garlic may be valuable in helping to control blood sugar and prevent long-term complications associated with type 2 diabetes and obesity. However, more studies are needed in this area before further conclusions on the potential benefits of garlic can be made.

Diabetes is associated with long-term complications that affect almost every part of the body. The disease often leads to blindness, heart and blood vessel disease, stroke, kidney failure, amputations, and nerve damage. Uncontrolled diabetes can complicate pregnancy, and birth defects are more common in babies born to women with diabetes. Pregnant women can temporarily develop gestational diabetes, a type of diabetes that begins late in pregnancy. In 2007, an estimated 20.8 million children and adults in the United States, or 7% of the population, had diabetes mellitus. An estimated 14.6 million have been diagnosed with diabetes (both type 1 and type 2), while 6.2 million people (or nearly one-third) are unaware that they have type 2 diabetes.

Garlic is a culinary herb that is widely used for the treatment and prevention of cardiovascular disease and cancer. Numerous controlled trials have examined the effects of oral garlic on serum lipids. Long-term effects on lipids or cardiovascular morbidity and mortality remain unknown. Other preparations (such as enteric-coated or raw garlic) have not been well studied.

Small reductions in blood pressure (<10 millimeters of mercury), inhibition of platelet aggregation, and enhancement of fibrinolytic activity have been reported, and may exert effects on cardiovascular outcomes, although evidence is preliminary in these areas.

Alpha lipoic acid (ALA) is another integrative therapy that has been studied for use in diabetes, and is supported by strong scientific evidence for this purpose. This compound is made naturally in the body and may protect against cell damage in a variety of conditions. Food sources rich in alpha lipoic acid include spinach, broccoli, and yeast. According to a survey of 685 herbalists, alpha lipoic acid was one of the 10 most frequently recommended dietary supplements due to its efficacy in reducing high blood sugar levels. The therapeutic use of alpha lipoic acid is not approved by the U.S. Food and Drug Administration (FDA) or corresponding regulatory agencies in other countries.

For more information about garlic, please visit Natural Standard's Foods, Herbs & Supplements Database.


  1. Kumar R, Chhatwal S, Arora S, et al. Antihyperglycemic, antihyperlipidemic, anti-inflammatory and adenosine deaminase- lowering effects of garlic in patients with type 2 diabetes mellitus with obesity. Diabetes Metab Syndr Obes. 2013;6:49-56. doi: 10.2147/DMSO.S38888. Epub 2013 Jan 19.
  2. Natural Standard: The Authority on Integrative Medicine. 

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