Science stacks up for CLAs weight management
increased lean body mass, adding to previous studies supporting the
weight management potential of the ingredient.
The randomised, double-blind, placebo-controlled trial, published in the Journal of Nutrition, assigned 48 participants to receive placebo, or one of two doses of CLA (3.2 or 6.4 grams per day) and found that the high dose CLA group experienced an increase in lean body mass of 0.64 kg. "We found that supplementation with 6.4 grams per day CLA for 12 weeks increases lean body mass in healthy obese adults, but has no significant effect on body fat mass, weight, BMI, resting energy expenditure, or respiratory quotient," wrote lead author Susan Steck from the University of North Carolina. There were, however, indications that the ingredient may increase markers of inflammation in the short-term although these never exceeded normal limits and the researchers concluded: "The intervention was well tolerated and no severe adverse events were reported." With 50 per cent of Europeans and 62 per cent of Americans classed as overweight, the food industry is waking up to the potential of products for weight loss and management, with the category already estimated to already be worth $7bn worldwide. The new study used Tonalin (50:50 ratio of cis-9, trans-11 and trans-10, cis-12 isomers, Cognis) and participants took the supplementation every day for 12 weeks. The placebo used was safflower oil (eight grams per day). Steck and co-workers measured changes in body fat mass and lean body mass using dual-energy X-ray absorptiometry, and blood samples were taken in order to determine haemoglobin levels, HDL-cholesterol levels and several markers of inflammation. "Our study adds to the evidence that CLA supplementation increases lean body mass but has no effect on body fat mass, weight, or BMI," wrote the researchers. "The 6.4 grams per day CLA supplemented group in our study increased lean body mass a mean of 0.64 kg and reported a significant decrease in physical activity during the intervention period, suggesting that the increase in LBM was related to CLA supplementation and not to a concomitant increase in training," they added. The researchers did not significant increases in serum alkaline phosphatase, C-reactive protein, and interleukin-6 but they stress that all these values remained within normal limits. "CLA is widely used in commercial supplements as well as being present in the diet, thus, these results need to be confirmed by future studies using varying doses of CLA over longer periods of time and in different patient populations," they concluded. Dr. Steck told NutraIngredients.com: "We do not have any other human studies on CLA currently ongoing, but one of my colleagues on the paper (Dr. Philippe Thuillier) is examining CLA effects on the carcinogenesis process in animal models." The study was supported by Cognis and the National Institutes of Health. Source: Journal of Nutrition May 2007, Volume 137, Pages 1188-1193 "Conjugated Linoleic Acid Supplementation for Twelve Weeks Increases Lean Body Mass in Obese Humans" Authors: S.E. Steck, A.M. Chalecki, P. Miller, J. Conway, G.L. Austin, J.W. Hardin, C.D. Albright, and P. Thuillier
