Herbs & Supplements:
Conjugated Linoleic Acid
Supplement Forms / Alternate Names
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CLA
Principal Proposed Uses
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There are no well-documented uses for conjugated linoleic acid.
Other Proposed Uses
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Reducing Body Fat, Diabetes, Cancer Prevention
Conjugated linoleic acid (CLA) is a mixture of different isomers, or chemical forms, of linoleic acid. Linoleic acid is an essential fatty acid—a type of fat that your body needs for optimum health.
Based on preliminary evidence, CLA has been promoted as a "fat-burning" supplement and a treatment for diabetes.
Requirements/Sources
Although linoleic acid itself is an important nutritional source of essential fatty acids, there is no evidence that you need to get conjugated linoleic acid in your diet. CLA does occur in food, but it would be very difficult to get the recommended dose that way. Supplements are the only practical source.
Therapeutic Dosages
The typical dosage of CLA ranges from 3 to 5 g daily. As with all supplements taken at this high a dosage, it is important to purchase a reputable brand, as even very small amounts of a toxic contaminant could quickly add up.
Therapeutic Uses
Preliminary and not entirely consistent evidence suggests that CLA might help you lose fat while retaining muscle, especially if you also engage in exercise.1–4,8,9 The net effect may be an improvement in body composition (ratio of muscle to fat) instead of weight loss. One study provides weak evidence that CLA might specifically reduce abdominal fat.10
During the course of investigations into its effect on fat, CLA was found to act somewhat similarly to some oral medications used for diabetes. This led to research into the possible usefulness of CLA as a treatment for diabetes. In one study, CLA reduced blood sugar levels in diabetic rats as effectively as a standard diabetes treatment.5 The same researchers also performed a small, double-blind, placebo-controlled trial in humans. The results showed that CLA improved insulin responsiveness in people with type 2 (adult onset) diabetes. Although this study is far too preliminary to prove that CLA is effective, it does point to a direction for future research.
Some animal and test tube studies suggest that CLA might help prevent cancer, but the evidence is preliminary and inconsistent. 7,11
Safety Issues
CLA appears to be a safe nutritional substance. However, one concern has been raised regarding nursing mothers. A double-blind, placebo-controlled study indicates that use of CLA reduces the fat content of human breast milk.12 Since infants depend on the fat in breast milk to provide adequate calories and on certain fats to aid proper growth and development, it is probably prudent for nursing mother’s to avoid CLA supplements. Maximum safe dosages of CLA for young children, pregnant women, or those with severe liver or kidney disease have not been determined.
View References
Last reviewed July 2002 by Medical Review Board
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