Intakes of nonfermented milk, cheese may raise T2D risk

Adults with high intakes of nonfermented milk and cheese appear to be at greater risk of developing type 2 diabetes (T2D), while those who consume fermented milk, cream, and butter show a lower risk, according to a study.

“These findings suggest that it is important to examine dairy products separately in relation to T2D because they differ in composition and structure,” the researchers said.

A total of 26,461 Swedish individuals were recruited between 1991 and 1996 and followed up until 31 December 2020 for this prospective cohort study. Participants had available data on dairy intake at baseline and linked registers.

The researchers used mass spectrometry to measure plasma metabolites in a subsample of 893 adults. They also used Cox proportional hazards models to explore the associations between dairy intake and T2D risk, with results presented as hazard ratios (HRs) and 95 percent confidence intervals (CIs).

During a median follow-up of 24.3 years, the research team recorded 4,552 cases of new-onset incident T2D. [Am J Clin Nutr 2025;121:1137-1148]

The risk of T2D was increased among individuals consuming high nonfermented milk (>1,000 vs <200 g/day; HR, 1.40, 95 percent CI, 1.12–1.74) and cheese (>100 g/day vs <20 g/day; HR, 1.23, 95 percent CI, 1.07–1.41).

On the other hand, lower T2D risk was seen among participants with high intakes of fermented milk (>300 vs 0 g/day; HR, 0.88, 95 percent CI, 0.74–1.03), cream (>50 vs <10 g/day; HR, 0.77, 95 percent CI, 0.64–0.92), and butter (>50 vs 0 g/day; HR, 0.82, 95 percent CI, 0.71–0.94). Additional adjustments for BMI slightly attenuated these associations.

Metabolomics

Moreover, metabolite profiles were identified for nonfermented milk (n=45), fermented milk (n=48), cheese (n=12), cream (n=27), and butter (n=46). Overlaps between metabolites were not found.

"[The] identified metabolites provide novel insights into potential pathways underlying the associations between dairy intake and risk of T2D,” the researchers said.

Previous studies of dairy intake and metabolomics measured small metabolite sets as opposed to thousands of measurable metabolites. The current study included 991 metabolites based on untargeted plasma metabolomics data. [Am J Clin Nutr 2021;114:163-174; Mol Nutr Food Res 2024;68:e2300154; J Nutr 2023;153:2994-3002; J Proteome Res 2017;16:3321-3335]

"Our results indicated that nonfermented milk, fermented milk, cheese, cream, and butter were all associated with different subclasses of sphingomyelins [positive coefficients except for sphingomyelin (d18:2/18:1) associated with butter],” the researchers said.

Additionally, findings from previous studies were consistent regarding the association between dairy intake and sphingomyelins, collectively suggesting that sphingomyelins are robust biomarkers of dairy intake. [J Nutr 2020;150:1272-1283; Hypertension 2022;79:1617-1628]

"Furthermore, our results showed that no metabolites identified in the study were associated with all five types of dairy intake, indicating that different types of dairy intake had different metabolic responses,” the researchers said. 

“These findings emphasize the importance of studying the associations between dairy products by type and risk of T2D,” they added.