Diet & Fitness

Conjugated linoleic acid (CLA) is a group of polyunsaturated fatty acids found mainly in dairy products. In numerous randomized controlled trials lasting from 12 weeks to two years, CLA supplementation has been found to reduce body fat in people with overweight and obesity.^1,2 Although some trials have reported weight loss attributable to CLA, others have found no effect of CLA on body weight.² A meta-analysis of seven placebo-controlled trials lasting six months or longer concluded CLA use is associated with small increases in weight loss and fat loss.⁴ One trial evaluated the effect of CLA on weight and fat regain in 101 participants with overweight or obesity who had lost 8% or more body weight: after one year, those taking 3.4 grams of CLA per day had regained the same amount of weight and fat as those taking placebo (olive oil).⁵ Importantly, conflicting evidence has emerged regarding the impact of CLA on oxidative stress and insulin resistance.^6,7,8 Therefore, the use of CLA by people with type 2 diabetes or signs of insulin resistance should be carefully monitored.

Conjugated linoleic acid (CLA) is a slightly altered form of the essential fatty acid linoleic acid. Animal research suggests an effect of CLA supplementation on reducing body fat.^8,9 Controlled human research has reported that 5.6 to 7.2 grams per day of CLA produces only non-significant gains in muscle size and strength in experienced and inexperienced weight-training men.^10,11,12 A double-blind study of a group of trained men and women reported reduced body fat in the upper arm after 12 weeks of supplementation with 1.8 grams per day of CLA.¹³ Further research using more accurate techniques for measuring body composition is needed to confirm these findings.

Preliminary animal and test tube research suggests that conjugated linoleic acid might reduce the risk of cancers at several sites, including breast, prostate, colorectal, lung, skin, and stomach.^14,15,16,17

Preliminary animal and test tube research suggests that CLA might reduce the risk of cancers at several sites, including breast, prostate, colorectal, lung, skin, and stomach.^18,19,20,21 Whether CLA will have a similar protective effect for people has yet to be demonstrated in human research.