Sequentially combined estradiol valerate plus levonorgestrel therapy decreases 18:1 trans-fatty acid content of plasma lipids in healthy postmenopausal women.

Trans-fatty acids (TFA) have been classified as atherogenic dietary constituents but the effect of hormone replacement therapy (HRT) on their concentrations is not known. We used a washout protocol to study the effect of long-term estrogen and combined estrogen-progestin HRT on plasma elaidate (18:1t), which is the trans isomer of oleate and the major TFA in the diet. The study group comprised 15 women receiving estradiol valerate HRT and 15 women receiving combined HRT with estradiol valerate and levonorgestrel.