Dairy product intake in relation to glucose regulation indices and risk of type 2 diabetes

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Abstract

Background and aim

A high intake of dairy has been linked to lower risk of type 2 diabetes (T2D). The relationship between dairy intake and glucose metabolism is still not well understood. The aim of this study was to investigate the relation between the intake of total dairy and dairy subgroups and T2D and measures of glucose metabolism.

Methods and results

A total of 5953 Danish men and women aged 30–60 years without baseline diabetes or cardiovascular diseases were included in this prospective analysis. The dairy intake at baseline was categorised into low-fat dairy, full-fat dairy, milk and milk products, cheese and fermented dairy. Fasting plasma glucose (FPG), 2-h plasma glucose (2hPG), HbA1c, insulin resistance (HOMA2-IR) and beta-cell function (HOMA2-B) were considered at 5-year follow-up. In the maximally-adjusted model (demographics, lifestyle factors, dietary factors and waist), cheese intake was inversely associated with 2hPG (β = −0.048, 95% CI −0.095; −0.001). Fermented dairy intake was inversely associated with FPG (β = −0.028, 95% CI −0.048; −0.008) and HbA1c (β = −0.016, 95% CI −0.030; −0.001). Total dairy intake and the dairy subgroups were not related to HOMA-IR and HOMA-B in the maximally-adjusted model. Furthermore, there was no significant association between intake of total dairy or any of the dairy subgroups and incidence of T2D.

Conclusion

Our data suggest a modest beneficial effect of cheese and fermented dairy on glucose regulation measures; however, this did not translate into a significant association with incident T2D.

Introduction

The main risk factors for type 2 diabetes (T2D) are obesity and lack of physical activity. There is accumulating evidence that besides energy intake also diet composition plays a role in determining the risk of T2D [1], [2], [3]. The role of dairy intake in glucose regulation and T2D risk remains largely unknown.

Dairy products make an important nutrient contribution to the diet in both developed and developing countries. Along with providing high-quality protein, dairy products are a good source of fat-soluble vitamins (vitamin A, D and K2), water soluble vitamins (vitamin B12 and riboflavin), and minerals (calcium, magnesium and potassium). Previous studies have shown that these nutrients are beneficially related to T2D risk [4]. Furthermore, whey which has been found to stimulate insulin secretion, is an important component of dairy products [5]. On the other hand, several dairy products such as cheese contain a high amount of fat, more than half of which is saturated. Evidence suggests that saturated fat intake has an adverse effect on insulin sensitivity and increases the risk of T2D [6].

Recent meta-analyses on the relationship between dairy intake and T2D show lower T2D risk with higher consumption of dairy products, especially low-fat dairy [7], [8], [9]. However, the exact mechanisms explaining this relationship remain unclear [7]. Studies examining the association between dairy products and glucose regulation indices such as fasting plasma glucose (FPG) and 2-h plasma glucose (2hPG) are needed to gain more insight into the relationship between dairy intake and T2D. Furthermore, examination of the different subgroups of dairy (low-fat dairy, full-fat dairy, milk and milk products, cheese and fermented dairy) may give more insight into the mechanism linking dairy products to metabolic disturbances because of their differences in nutrient composition which might have different effects on the risk of developing T2D.

The aim of this study was to investigate the association of dairy intake, including specific dairy subgroups, with T2D incidence and glucose regulation indices.

Section snippets

Study design

Data for the present study originated from the Inter99 study, a Danish population-based lifestyle intervention study aiming to evaluate the effect of lifestyle intervention on incidence of ischaemic heart disease. The Inter99 study has been described in detail elsewhere [10].

Briefly, the initial Inter99 study population comprised 61,301 men and women aged 30–60 years residing in the Copenhagen County. An age- and sex-stratified random sample of 13,016 individuals was drawn from the study

Results

After 5 years of follow-up 214 incident T2D cases were documented. The median total dairy intake of the study population was 204 g/d (Table 1). Low-fat dairy with a median of 155 g/d made the largest contribution to dairy intake. The median daily intakes were 17 g/d for full-fat dairy, 188 g/d for milk and milk products, 19 g/d for cheese and 59 g/d for fermented dairy (see Supplemental Table 1 for quartiles of dairy intake).

There was no significant association between total dairy intake and

Discussion

In this study among middle-aged Danish men and women we found a modest inverse association of cheese intake with 2hPG and of fermented dairy intake with FPG and HbA1c, We did not however find evidence for a relation between intake of total dairy or any specific dairy subgroup and incident T2D.

Acknowledgements

The Inter99 study was initiated by Torben Jørgensen (Principal Investigator), Knut Borch-Johnsen (Principal Investigator, diabetes part), Hans Ibsen and Troels Thomsen. The Inter99 steering committee comprises Torben Jørgensen, Knut Borch-Johnsen and Charlotta Pisinger.

The Inter99 study was supported by the Danish Medical Research Council, the Danish Centre for Evaluation and Health Technology Assessment, Novo Nordisk A/S, Copenhagen County, the Danish Heart Foundation, the Danish Diabetes

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    Present address: Julius Center for Health Sciences and Primary Care, UMC Utrecht, P.O. Box 85500, 3508 GA Utrecht, The Netherlands.

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