Major Review Finds Naturally Occurring Dairy Trans Fats May Not Pose the Same Risks

Naturally occurring trans fats in dairy products such as milk, butter, yogurt and cheese may not carry the same health risks as industrial trans fats, according to a review published in Nutrition Research.

Researchers examined evidence from 22 studies involving participants from Europe, Ca Major Review Finds Naturally Occurring Dairy Trans Fats May Not Pose the Same Risks nada and the United States to investigate the relationship between dairy trans fats and cardiovascular health and type 2 diabetes.

The review included ten controlled dietary trials and 12 long-term observational studies.

In the controlled trials, participants consumed dairy products containing different levels of naturally occurring trans fats. Researchers assessed blood lipid levels, which are commonly used to evaluate cardiovascular risk.

Across the ten trials, daily trans fat intake ranged from 1.3 to 13.2 grams. The findings showed no meaningful differences in blood lipid levels between participants consuming dairy products with higher natural trans fat content and those consuming regular dairy products.

The researchers also analysed 12 long-term studies that followed participants over several years, with some lasting more than two decades.

Higher blood levels of dairy trans fats were not associated with an increased risk of heart disease, stroke or cardiovascular death. Researchers also found no association between these fats and an increased risk of developing type 2 diabetes.

Trans fats occur naturally in the milk of ruminant animals, including cows, sheep and goats. Industrial trans fats, meanwhile, are produced during processes such as the partial hydrogenation of oils and have been strongly linked to cardiovascular disease.

The findings suggest that naturally occurring dairy trans fats may have different health effects from their industrial counterparts.

However, researchers emphasised that the results do not establish that dairy products are universally beneficial or that unlimited consumption is advisable.

The study provides further evidence that the health effects of fats can vary depending on their source and composition. Further research may help clarify these differences and inform dietary guidance.

REFERENCE: Constance Gayet-Boyer, et al.; 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, 2026; 150: 33 DOI: 10.1016/j.nutres.2026.03.009