Dietary supplementation with cis-9,trans-11 conjugated linoleic acid and aortic stiffness in overweight and obese adults.

Single-center randomized placebo-controlled trial in apparently healthy overweight and obese adults in Utrecht, Netherlands. Participants were 40 to 70 years old; in the CLA active arm, 201 were randomized and 173 were analyzed.

Adults in the active arm received four 1 g capsules daily of c9,t11 conjugated linoleic acid (CLA) oil for 6 months, for a total dose of 4 g/day. The supplement provided 2.5 g/day c9,t11 CLA and 0.6 g/day t10,c12 CLA, administered orally; compliance was monitored.

CLA supplementation did not improve aortic stiffness or cardiovascular risk factors. The primary endpoint, change in aortic PWV, was 0.00 ± 0.07 m/s in the CLA group versus 0.09 ± 0.06 m/s with placebo, with a between-group difference of -0.09 (-0.29, 0.09; P = 0.31). There were also no significant between-group differences in central or peripheral blood pressure, weight, BMI, waist measures, plasma lipids, glucose, insulin, HOMA-IR, or hs-CRP. Safety findings were similar overall, with 188 adverse events in 102 CLA participants versus 170 in 94 placebo participants (P = 0.59), and serious adverse events were unrelated to CLA.

The study duration was only 6 months, and the analyzed active-arm sample was smaller than the randomized sample. Generalizability is limited by the apparently healthy overweight/obese population, lack of reported ethnicity data, and minimal baseline dietary characterization. No benefit was seen on the primary endpoint or on multiple secondary cardiovascular risk markers.