Linoleic acids are common omega-6 polyunsaturated fatty acids. These essential fatty acids are not made in the body and must be obtained from food. The Institute of Medicine Food and Nutrition Board recommends a daily linoleic acid intake of 5 to 6 percent of total calories, and most people consume 6.7 percent, according to a 2009 issue of "Circulation." Most studies addressing linoleic acid and weight loss refer to conjugated linoleic acid, or CLA.
CLA Overview
While linoleic acid is found in plant oils, CLA is found in meat and dairy products. When linoleic acid is consumed by grazing animals like cows, bacteria in the digestive system convert the fatty acid into CLA. The amount of CLA found naturally in food sources is much lower than in supplement form. The MayoClinic.com claims CLA is possibly effective and safe when used to reduce fat and build muscle.
CLA and Animal Studies
Studies on rodents have shown promising results for CLA's use as a weight loss aid. A 2004 review in "International Journal of Obesity" found that when rodent diets were supplemented with higher doses of CLA, they showed a more significant weight loss than the rodents supplemented with lower doses. Adding CLA to the diets of mice, hamsters and rats also decreased body fat, decreased food intake and increased metabolism.
CLA and Human Studies
Results of CLA use in human studies are conflicting and less favorable than animal studies, according to a 2004 review in "The American Journal of Clinical Nutrition." CLA supplementation caused a modest reduction in body fat in five studies reviewed. Unlike the animal studies, CLA did not increase energy expenditure or decrease in food intake in human studies. Three other studies cited in the review found no weight loss benefit of CLA supplementation.
Considerations
It is still unclear whether CLA can aid in weight loss based on human studies. Long-term safety and efficacy of CLA has not been determined. Since supplements are not regulated by the Food and Drug Administration, consult your doctor before starting any dietary supplement. For a healthier way to lose weight, opt for a diet rich in low-calorie, filling foods like fruits, vegetables, whole grains and lean proteins.
References
- "Circulation"; Omega-6 Fatty Acids and Risk for Cardiovascular Disease: A Science Advisory from the American Heart Association Nutrition Subcommittee of the Council on Nutrition, Physical Activity, and Metabolism; Council on Cardiovascular Nursing; and Council on Epidemiology and Prevention; William S. Harris, et al.; January 2009
- MayoClinic: Over-the-Counter Weight Loss Pills: Do they Really Work?
- "International Journal of Obesity and Related Metabolic Disorders"; Conjugated Linoleic Acid and Obesity Control: Efficacy and Mechanisms; Y.W. Wang and P.J.H. Jones; 2004
- "The American Journal of Clinical Nutrition"; Dietary Conjugated Linoleic Acid and Body Composition; Yanwen Wang and Peter J.H. Jones; June 2004
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