Can a diet that includes plenty of dairy foods cut your risk of developing type 2 diabetes?

Milk drinking has declined over the past 30 years. During this same time, the prevalence of obesity and type 2 diabetes has increased. Is this just a coincidence, or are the two trends related? Harvard University researchers recently took a look at this question by examining the relationship between dairy consumption, obesity, and factors leading to the development of type 2 diabetes in young adults.

Their focus was on health factors --- including obesity and abnormally high levels of insulin in the bloodstream --- that appear to contribute to high blood pressure, abnormal blood sugar levels, low HDL (good) cholesterol, and elevated blood triglycerides. This cluster of risk factors, called the insulin resistance syndrome (IRS) or syndrome X, is linked to an increased risk of type 2 diabetes and heart disease.

A look at diet and lifestyle

For this analysis, more than 3,000 young adults from 4 US cities completed a questionnaire that documented lifestyle habits, including smoking status, physical activity, and diet. A physical exam and blood tests measured blood pressure, cholesterol levels, blood sugar levels, and body fat.

Study participants were monitored over a 10-year period, and were diagnosed with insulin resistance syndrome if they had at least two of the following symptoms: high blood sugar, obesity, high blood pressure, and a combination of low HDL cholesterol and high triglycerides.

Dairy foods benefit overweight adults

Among the volunteers who were somewhat overweight, there was a significantly lower incidence of IRS characteristics --- obesity, high blood pressure, abnormal blood sugar levels --- in those who ate more dairy foods. Those who ate at least 5 servings per day (of milk, cheese, yogurt, and dairy-based desserts) reduced their odds of developing IRS by 72%, even after taking into consideration other dietary and lifestyle factors that affect the likelihood of developing IRS.

In normal weight individuals, there was no consistent pattern between dairy consumption and development of IRS.

Why dairy?

Scientists aren't yet sure how specific foods might affect the risk of developing IRS. They speculate, though, that the protective benefits of dairy products may come from calcium, potassium, and magnesium --- all of which may lower the risk of high blood pressure, coronary heart disease, stroke, or type 2 diabetes.

Insulin resistance syndrome, type 2 diabetes, and cardiovascular disease are on the rise in all racial, ethnic, and social class groups. Even children and young adults are developing these diseases at higher rates. The authors point out that dietary trends such as increased soda consumption (which often displaces milk) and snacking may contribute to overweight and poor health.

Make dairy decisions wisely

The downside of dairy is the high amount of saturated fat it contains. But consumers can minimize fat and calories by choosing low-fat and fat-free milk, yogurt, and cheese.

Source

• Dairy consumption, obesity, and the insulin resistance syndrome in young adults: The CARDIA Study. MA. Pereira, DR. Jacobs, L. Van Horn,  et al., JAMA , 2002, vol. 287, pp. 2081--2089

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Healthful Habits Can Prevent Type 2 Diabetes
Syndrome X -- Again
Milk is Good For Bones . . . .and the Heart, Too
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