Trans fatty acids from dairy foods do not affect risk of cardiometabolic diseases: systematic review and meta-analysis of evidence from randomized controlled trials and systematic review of prospective cohort studies

Gayet-Boyer, C., Tenenhaus-Aziza, F., Torres-Gonzales, M., Givens, D. I. and Schweitzer, C. (2026) Trans fatty acids from dairy foods do not affect risk of cardiometabolic diseases: systematic review and meta-analysis of evidence from randomized controlled trials and systematic review of prospective cohort studies. Nutrition Research. ISSN 0271-5317 doi: 10.1016/j.nutres.2026.03.009 (In Press)

Abstract/Summary

Dairy foods are becoming one of the major dietary source of trans fatty acids (TFA) as global initiatives to eliminate industrially-produced TFA (iTFA) are implemented. This systematic review aimed to assess cardiometabolic effects of TFA from dairy foods, using data from randomized controlled trials (RCTs) and prospective cohort studies (PCS). We hypothesized that TFA from dairy foods would have no effect on biomarkers for or risk of cardiovascular diseases. Searches for RCTs and PCS were conducted in PubMed and EMBASE using PRISMA guidelines. RCTs compared the impact on blood lipids of regular dairy foods with TFAenhanced dairy fat/foods produced by altering the cow’s diet. Pooled meta-analysis of RCTs using the random effects model was performed for TC, LDL-C, HDL-C, TC/HDL-C, LDL-C/HDL-C, TG, ApoA1, ApoB as continuous variables. Selected PCS analyzed associations between blood concentrations of trans vaccenic acid or trans palmitoleic acid (TPA) and risk of cardiovascular diseases (CVD) or type 2 diabetes. Among ten RCTs, there were no significant differences in mean difference (MD) for any lipid biomarkers except a slight decrease in HDL-C (MD: -0.05 mmol/L; CI: -0.10, -0.00 mmol/L) for TFA-enriched vs regular dairy foods. Among 12 PCS, circulating concentrations of trans vaccenic acid or TPA were not associated with increased risk of CVD incidence, mortality or type 2 diabetes. Consumption of TFA (1.3 – 13.2 g/d) from different types of dairy foods was not linked with adverse effects on cardiometabolic health.