The effect of conjugated linoleic acid, a natural trans fat from milk and meat, on human blood pressure: results from a randomized crossover feeding study

Abstract

Cis-9, trans-11 conjugated linoleic acid (CLA) is a natural trans fatty acid that is largely restricted to ruminant fats and consumed in foods and supplements. Its role in blood pressure (BP) regulation is still unclear. We examined the effect of cis-9, trans-11 CLA on BP compared with oleic acid. A total of 61 healthy volunteers were sequentially fed each of 3 diets for 3 weeks, in random order, for a total of 9 weeks. The diets were identical except for 7% of energy (18.9 g in a diet of 10 MJ day(-1)) that was provided either by oleic acid, by industrial trans fatty acids or by cis-9, trans-11 CLA. We measured BP on two separate days at the end of each intervention period. At baseline, mean BP was 113.8±14.4 mm Hg systolic and 66.3±9.6 mm Hg diastolic. The effect of the CLA diet compared with the oleic acid diet was 0.11 mm Hg (95% confidence interval: -1.27, 1.49) systolic and -0.45 mm Hg (-1.63, 0.73) diastolic. After the industrial trans fatty acid diet, the effect was 1.13 mm Hg (-0.25, 2.51) systolic and -0.44 mm Hg (-1.62, 0.73) diastolic compared with the oleic acid diet. Our study suggests that short-term high intakes of cis-9,trans-11 CLA do not affect BP in healthy volunteers.