This study investigated the relationship between the consumption of too many dairy products during adolescence and the risk of acquiring type 2 diabetes in adulthood. For this study, 37,038 women had answered questionnaires on food frequency, providing details about their diet during high school. Follow-up studies were then conducted on these participants for seven years, from 1998 to 2005, to assess the incidence of type 2 diabetes in them. Those who reported a higher consumption of dairy products in adolescence were found to have 38 percent lower risk for type 2 diabetes.
In view of the growing incidence of type 2 diabetes in the United States, as well as across the world, factors that increase the risk of developing it are being investigated. Most of the studies on type 2 diabetes have been confined to adults. However, recent evidence suggests that type 2 diabetes is affected by diet patterns, right from the diet of the mother during pregnancy to the diet during postnatal, childhood and adolescent stages. Low weight at birth and less height in adulthood, which are common indicators of low levels of nutrition, are associated with increased risk of type 2 diabetes. In light of evidence that dairy consumption in adults has a negative effect on metabolic syndrome and type 2 diabetes, the researchers of this study attempted to investigate whether the consumption of dairy in adolescence has any effect on the risk of type 2 diabetes in adulthood.
* The study involved 37,038 nurses, aged 34 to 53, who answered a questionnaire about their diet during their high school years. They reported quantities and frequencies of consumption of food items like milk, yogurt, cheese, milkshakes and ice cream.
* The data was converted to nutritional values and average dairy consumption per day. Data on consumption of processed food, meats, sugar, alcohol, etcetera, was also recorded.
* Women who were diagnosed with diabetes during the follow-up studies were asked to answer another supplementary questionnaire about the clinical details of their diagnosis. These were confirmed by reviewing their medical records.
* Their current dairy consumption habits were also recorded.
* Typically, women who had higher dairy consumption were more active and also put on less weight in adulthood. They often started menstruating before 12 years of age, and were above average in height.
* Most participants with a higher dairy intake during adolescence continued it in adulthood.
* In follow-up studies, 550 type 2 diabetes cases were recorded. Dairy consumption was inversely related to type 2 diabetes prevalence, both during adolescence and in adulthood. The degree, however, varied based on physical activity and body-mass index since the age of 18 years.
* The negative correlation between dairy consumption (during adolescence and adulthood) and the risk of type 2 diabetes was dose-dependent.
Correlation between dairy consumption and growth factors could not be tested due to lack of blood samples from the participants. Therefore, it could not be ascertained whether the effect of dairy consumption on the risk of type 2 diabetes was due to the presence of growth factors or other components in dairy products.
Greater consumption of dairy during adolescence and its continuation in adulthood reduces the risk of type 2 diabetes. This association, however, is weaker in people who put on weight in adulthood due to other factors. Components like calcium, magnesium and protein in dairy effectively reduce the risk of hypertension, obesity, and other issues commonly associated with diabetes. A low-fat dairy diet is twice as effective in reducing hypertension as is a fruit and vegetable diet. The study recommends an early and continued habit of low-fat dairy intake to reduce the risks of type 2 diabetes and related disorders. The authors of this study suggest further evaluation and examination of the mechanisms underlying the effects of dairy on the incidence of type 2 diabetes.
For More Information:
Adolescent Dairy Product Consumption and Risk of Type 2 Diabetes in Middle-Aged Women
Publication Journal: American Journal of Clinical Nutrition, July 2011
By Vasanti S. Malik; Qi Sun; Harvard School of Public Health, Boston, Massachusetts