Conjugated linoleic acid supplementation for twelve weeks increases lean body mass in obese humans.
What this study found
Overall, CLA did not reduce body weight or body fat mass, but the 6.4 g/day dose increased lean body mass. Lean body mass changed by 0.64 kg with 6.4 g/day (P < 0.05) and by 0.65 kg with 3.2 g/day (P = 0.18), while resting energy expenditure and respiratory quotient did not change in any group. The higher dose also increased inflammatory markers, including C-reactive protein (P = 0.03), IL-6 (P = 0.04), and white blood cells (P = 0.005), and altered several laboratory values. Adverse events were reported by 13 participants (27%) overall.
- Study & population
- Randomized, placebo-controlled, 12-week trial in healthy obese adults aged 18 to 50 years with BMI 30 to 35 kg/m^2, who were nonsmokers and had no chronic disease.
- Intervention
- Two oral conjugated linoleic acid (CLA) regimens were tested: 3.2 g/day and 6.4 g/day, using Tonalin capsules containing cis-9, trans-11 and trans-10, cis-12 isomers in a 50:50 ratio.
- Key limitation
- The active arms were small (n = 16 each), the intervention lasted only 12 weeks, and the population was limited to otherwise healthy obese adults, which restricts generalizability.
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Open PDFOriginal abstract
Conjugated linoleic acid (CLA) alters body composition in animal models, but few studies have examined the effects of CLA supplementation on body composition and clinical safety measures in obese humans. In the present study, we performed a randomized, double-blind, placebo-controlled trial to examine the changes in body composition and clinical laboratory values following CLA (50:50 ratio of cis-9, trans-11 and trans-10, cis-12 isomers) supplementation for 12 wk in otherwise healthy obese humans. Forty-eight participants (13 males and 35 females) were randomized to receive placebo (8 g safflower oil/d), 3.2 g/d CLA, or 6.4 g/d CLA for 12 wk. Changes in body fat mass and lean body mass were determined by dual-energy X-ray absorptiometry. Resting energy expenditure was assessed by indirect calorimetry. Clinical laboratory values and adverse-event reporting were used to monitor safety. Lean body mass increased by 0.64 kg in the 6.4 g/d CLA group (P < 0.05) after 12 wk of intervention. Significant decreases in serum HDL-cholesterol and sodium, hemoglobin, and hematocrit, and significant increases in serum alkaline phosphatase, C-reactive protein, and IL-6, and white blood cells occurred in the 6.4 g/d CLA group, although all values remained within normal limits. The intervention was well tolerated and no severe adverse events were reported, although mild gastrointestinal adverse events were reported in all treatment groups. In conclusion, whereas CLA may increase lean body mass in obese humans, it may also increase markers of inflammation in the short term.