What is it?
Although Conjugated Linoleic Acid (CLA) is marketed as a supplement for weight loss and to lower cholesterol levels, human studies on potential benefits are limited and mixed.
CLA is commonly found in dairy products and beef, and is made by microbes that live within the gut of certain animals. It is also found throughout the body. CLA is often marketed as a supplement for weight loss.
Animal studies suggest CLA supplementation may improve insulin sensitivity and blood lipid profiles, decrease body fat, and reduce risks for cancer and cardiovascular disease. However, many of these effects have not been replicated in humans, or studies show mixed results. In addition, there is also a concern for potential increase risk of cardiovascular disease with high CLA intake. Therefore more well-designed studies are needed to determine under what conditions CLA supplementation demonstrates safety and any benefits.
What are the potential uses and benefits?
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To prevent and treat cancer
Although animal studies suggest CLA has antioxidant properties and may reduce cancer risk, studies in humans are limited and mixed. Therefore, clinical trials to confirm safety and effectiveness are needed. -
To treat high cholesterol
Although a few studies suggest CLA may reduce a type of fat in the blood called triacylglycerols, it was shown to increase total cholesterol and may also reduce HDL, or good cholesterol levels. -
To promote healthy weight
CLA may improve body fat mass in some people, but results are mixed, and CLA may actually be harmful in some populations. For example, in obese men with metabolic syndrome or at high risk for heart disease, CLA supplementation decreased insulin sensitivity or caused insulin resistance. In addition, it does not appear to enhance the benefits of exercise.
What are the side effects?
- Fatigue
- Gastrointestinal symptoms
Case reports
- Migraine visual disturbance: In an older adult man without prior migraine history, and related to several separate instances of taking a CLA supplement.
- Sudden, intense headache: In a 50-year-old black woman after starting an herbal weight loss supplement containing CLA, green tea, and L-carnitine.
What else do I need to know?
Do Not Take if:
You have diabetes: In obese men, CLA has caused insulin resistance and may increase blood glucose levels.
You have heart disease: In patients at risk for cardiovascular complications, it may increase processes that cause cell damage.