Fatty acid biomarkers of dairy fat consumption and incidence of type 2 diabetes

This October 2018 analysis combined data from 16 prospective cohort studies across 12 countries to assess the relationship between dairy fat consumption and Type 2 diabetes (T2D). The researchers intended to use biomarkers to assess dairy fat intake to overcome the known reliability issues in dietary recall data.

In total, 63,682 adults free of T2D at baseline were observed for up to 20 years; 15,158 developed T2D over this period. Circulating concentrations of specific dietary fats (15:0, 17:0, and trans-16:1n7) were assessed as markers of dairy consumption due to their high prevalence in dairy fat.

Across all studies, each of these dairy fat consumption biomarkers, and the set of all three in total, was associated with reduced risk of T2D, with the difference between the top and bottom quintiles reflecting a 29% reduction. The authors conclude:

These novel findings support the need for additional clinical and molecular research to elucidate the potential effects of these fatty acids on glucose–insulin metabolism and the potential role of selected dairy products for the prevention of T2D.

It is worth noting, however, the many caveats to this study. The authors acknowledge that using an objective measure of dietary fat intake (circulating levels of specific fats) removes the subjective biases inherent to dietary recall but does not perfectly track dairy consumption. The magnitude of effect was relatively small and not consistently seen across all studies. More important, because this was an observational study, the usual caveats apply: In particular, it is possible that dairy consumption served as a proxy for some other behavior that more directly prevents T2D.