New study reveals how dairy products like non-fermented milk and cheese may increase the risk of type 2 diabetes, while fermented options provide a surprising protective effect. Find out which dairy could be a game-changer for your health!
Study: Dairy intake, plasma metabolome, and risk of type 2 diabetes in a population-based cohort. Image Credit: Africa Studio / Shutterstock
A new study involving Swedish adults finds that high intake of non-fermented milk and cheese can increase the risk of type 2 diabetes. The study findings are published in The American Journal of Clinical Nutrition.
Background
Diabetes, a chronic metabolic condition characterized by high blood glucose levels, is becoming a major public health concern worldwide, with a projected increase in its prevalence from 537 million in 2021 to 783 million by 2045. Type 2 diabetes accounts for more than 90% of all diabetic cases.
Diet is one of the major modifiable risk factors for type 2 diabetes. Dairy products are vital components of any diet, and the dietary components present in these products are considered essential for growth and immune function.
Regarding the associations between dairy product intake and the risk of type 2 diabetes, studies have produced mixed results, with some reporting inverse associations and others suggesting neutral associations.
Existing evidence also suggests a link between higher intake of dairy products and increased risk of type 2 diabetes. However, studies investigating diabetes risk with very high intakes are lacking due to a lack of data among populations with high dairy consumption.
Sweden is among the countries with the highest intake of dairy products worldwide. Various dairy products are consumed in regular diets in this country. These factors present a suitable opportunity for researchers to investigate the association between various types of dairy products and the risk of type 2 diabetes, with a particular focus on the level of consumption.
In this study, researchers utilized high-quality dietary data from a group of Swedish adults to investigate the impact of high intakes of different dairy products on the risk of type 2 diabetes. They also explored plasma metabolites associated with dairy intake.
Study Design
The study analyzed dairy intake data from 26,461 Swedish individuals who participated in the Malmö Diet and Cancer Study (MDCS) between 1991 and 1996 and were followed up until December 31, 2020.
Dairy products analyzed in the study included non-fermented milk, fermented milk (yogurt and sour milk), cheese, cream, and butter.
To identify plasma metabolites associated with dairy intake, a subgroup of 893 participants with data on metabolomics and dairy intake was analyzed separately in this study. Metabolites are end products of metabolic reactions that serve as crucial biomarkers of dietary intake. Assessment of plasma metabolite levels can provide novel insights into the molecular mechanisms underlying the relationship between dairy products and type 2 diabetes.
Study Findings
About 17% of study participants (4,552 out of 26,461 participants) developed type 2 diabetes during the average follow-up period of 24 years.
The analysis, adjusting for demographic characteristics, lifestyle factors, dietary intake, and body mass index (BMI), revealed that high consumption of non-fermented milk and cheese can significantly increase the risk of developing diabetes; however, these associations were attenuated after accounting for BMI (e.g., non-fermented milk hazard ratio [HR] dropped from 1.40 to 1.15), suggesting body weight may partially mediate the observed effects. In contrast, high consumption of fermented milk, cream, and butter was associated with significantly reduced risk of diabetes.
Specifically, the study found that a 100-gram increase in daily intake of non-fermented milk and fermented milk is associated with a 4% increased risk and a 3% reduced risk of type 2 diabetes, respectively.
Notably, the study found that the association between dairy product intake and diabetes risk is independent of participants’ socioeconomic status. Similarly, no significant impact of participants’ gender was observed on the association between intakes of non-fermented milk, fermented milk, cream, and butter and the risk of diabetes. However, the negative impact of cheese intake on diabetes risk was observed more strongly in male participants, a notable sex-specific finding, but not in female participants.
By analyzing metabolomic data, the study identified 45, 48, 12, 27, and 46 metabolites that were distinctly associated with the intakes of non-fermented milk, fermented milk, cheese, cream, and butter, respectively.
Plasma metabolite profiles of fermented milk exhibited positive associations with intakes of vegetables, fruits, and dietary fibers, and inverse associations with meat intake. In contrast, the metabolite profile of butter exhibited inverse associations with dietary fiber intake.
Study Significance
The study reveals that high intake of non-fermented milk can significantly increase type 2 diabetes risk among Swedish men and women. A similar positive association between very high cheese intake and diabetes risk has also been observed in the study. However, this association is restricted only to male participants.
In contrast to the modest health impact of these dairy products, the study finds that higher intakes of fermented milk, cream, and butter have modest protective effects on the risk of type 2 diabetes among both Swedish men and women. These protective associations were weaker after adjusting for BMI (e.g., butter HR increased from 0.82 to 0.86), implying that body weight may play a mediating role.
Notably, the study identifies sphingomyelins as robust plasma biomarkers of dairy intake. Furthermore, a strong association was observed between a xenobiotic metabolite and non-fermented milk intake in the study. This metabolite, which belongs to the class of organic compounds known as salicylic acids, can serve as a novel biomarker for dairy intake.
For fermented milk, the strongest association has been observed with arabonate/xylonate, a metabolite associated with pentose metabolism. Probiotics in fermented milk may be involved in this process. For cheese, the study identifies three novel plasma biomarkers that need further investigation for a more conclusive interpretation.
Limitations
The study measured dairy intake only at baseline. This could be a potential limitation, as any changes in dairy intake during the 24-year follow-up period may influence the observed associations with diabetes risk.
Moreover, the study was conducted with Swedish middle-aged participants, which may limit the generalizability of the findings to populations of different ethnicities and age groups.