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

ABSTRACT

Conjugated linoleic acid [CLA] has been shown to positively influence calcium and bone metabolism in experimental animals and cell culture, but there are limited human data available. The study consisted of a double-blind, placebo-controlled trial in which 76 healthy post-menopausal women [aged 55.1] were randomly assigned to receive daily either four capsules CLA G80 containing 3.2 g isomer blend [5050% 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-alpha and IL-6]. Subjects completed 3-days dietary records during the trial, in weeks 0 [baseline], 6 and 12. Supplementation with 3.2 g CLA isomer blend [5050% cis-9,trans-l ltrans-10,cis-12 isomers] for 12 weeks had no significant effects on markers of bone formation [serum osteocalcin, bone-specific alkaline phosphatase] or bone resorption [urine C-telopeptide-related fraction of type 1 collagen degradation products], PTH, urinary calcium, urinary creatinine and CTP to creatinine ratio. And serum interIeukine-6 did not change significantly over 12 weeks in postmenopausal women. Under the conditions tested in this double-blind, placebo-controlled trial in postmenopausal women, 3.2 g CLA isomer blend [5050% cis-9, trans-11 trans-10, cis-12 isomers] did not affect markers of bone metabolism and calcium