Effect of Dietary Supplementation with Conjugated Linoleic Acid on Bone Mineral Density, Bone Metabolism Markers and Inflammatory Markers in Healthy Post-menopausal Women: a Randomized Double Blind Placebo Controlled Trial

Conjugated linoleic acid (CLA) has been shown to positively influence on calcium and bone metabolism in experimental animals and cell culture, but there are limited human data available. This double-blind, placebo-controlled trial study was done on 76 healthy post-menopausal women (aged 55.1) which randomly assigned to receive daily four CLA capsules G80 containing 3.2 g isomer blend (50:50% cis-9, trans-11: trans-10, cis-12 isomers) or four capsules containing high oleic sunflower oil as placebo for 12 weeks. Urine and blood samples were collected at weeks 0 and 12 and were analyzed for biomarkers of calcium and bone metabolism and inflammatory markers (TNF-α and IL-6). Subjects completed 3-day dietary records during the trial, in weeks 0 (baseline), 6and 12. supplementation with 3.2 g CLA isomer blend (50:50% cis-9,trans-11:trans-10,cis-12 isomers) for 12 weeks had no significant effects on bone formation markers (serum osteocalcin, bone-specific alkaline phosphatase) or bone resorption (urine C-telopeptide-related fraction of type 1 collagen degradation products), parathyroid hormone (PTH), urinary calcium, urinary creatinine and CTP to creatinine ratio. But serum interlukine-6 did not change significantly over 12 weeks in postmenopausal women. Under the conditions tested in postmenopausal women, 3.2 g CLA isomer blend (50:50% cis-9, trans-11: trans-10, cis-12 isomers) did not affect markers of bone metabolism and calcium.