Dairy intake, plasma metabolome, and risk of type 2 diabetes in a population-based cohort

Whether dairy intake is related to type 2 diabetes (T2D) remains unclear, as does potential metabolic mechanisms for this association.

We aimed to examine the association between high dairy intake and risk of T2D and identify plasma metabolites reflecting dairy intake.

This prospective cohort study included 26,461 Swedish individuals recruited between 1991 and 1996 and followed up until 31 December, 2020, with available data on dairy intake at baseline and linked registers. Plasma metabolites were measured in a subsample (n = 893) using mass spectrometry. Associations of dairy intake with risk of T2D were assessed using Cox proportional hazards models, with results presented as hazard ratios (HRs) and 95% confidence intervals (CIs).

A total of 4552 new-onset incident T2D cases were documented during a median follow-up of 24.3 y. Increased risk of T2D was observed among participants consuming high nonfermented milk (>1000 g/d compared with <200 g/d; HR: 1.40; 95% CI: 1.12, 1.74) and cheese (>100 g/d compared with <20 g/d; HR: 1.23; 95% CI: 1.07, 1.41), although decreased risk of T2D was observed among those with high fermented milk (>300 g/d compared with 0 g/d; HR: 0.88; 95% CI: 0.74, 1.03), cream (>50 g/d compared with <10 g/d; HR: 0.77; 95% CI: 0.64, 0.92), and butter (>50 g/d compared with 0 g/d; HR: 0.82; 95% CI: 0.71, 0.94). Such associations were slightly attenuated after additional adjustment for BMI. In addition, we identified metabolite profiles for nonfermented milk (n = 45), fermented milk (n = 48), cheese (n = 12), cream (n = 27), and butter (n = 46); no overlap between metabolites was found.

In this cohort of Swedish adults, high intakes of nonfermented milk and cheese are positively associated with risk of T2D, although high intakes of fermented milk, cream, and butter are inversely associated. Metabolomics provides novel insights into understanding the metabolic pathways of these associations.