Objective The aim of this study was to determine short-term effects of trans fatty acid (TFA) intake from ruminant and industrial sources on surrogate markers of cardiovascular risk in the context of a balanced diet with 30-36% of daily energy from fat. Design Prospective, randomized, double-blind, parallel-design study. Methods In this study, 142 healthy volunteers aged 45 to 69 years were randomly allocated to three different diets: either a diet enriched with 2% of daily energy intake from ruminant TFA (rTFA) or with industrial TFA (iTFA), or a diet without TFA (wTFA), for a duration of four weeks. The primary outcome parameter was endothelial function measured by brachial artery flow mediated dilation (FMD). Secondary outcome parameters included biomarkers for inflammation, coagulation and endothelial function and lipid profiles. One hundred and twenty-nine participants completed the study. Results Neither alpine butter with TFA from ruminant source nor margarine with industrially produced TFA showed significant effects on brachial artery FMD (FMD% differences: rTFA vs. iTFA 0.04 (95% confidence interval 0.91 to 0.98), rTFA vs. wTFA -0.98 (-2.00 to 0.04) and iTFA vs. wTFA -1.04 (-2.38 to 0.30). With rTFA, there was a small but significant increase of total cholesterol: rTFA over wTFA 1.04 (1.00 to 1.07 mmol/l) and LDL-cholesterol: rTFA over wTFA 1.08 (1.03 to 1.14 mmol/l) without concomitant increase of biomarkers for inflammation or coagulation. Conclusions Short-term intake of TFA at 2% of total daily energy intake from neither ruminant nor industrially produced sources does not have any negative impact on brachial artery FMD, inflammation and coagulation markers in healthy subjects.
Trial registration: ClinicalTrials.gov NCT00933322.
Keywords: Endothelial function; adhesion molecule; alpine butter; coagulation; flow-mediated dilation; inflammation; trans fatty acid.