In two reports published in the American Journal of Clinical Nutrition, separate groups of European researchers determined that egg consumption and high-fat yogurt and cheese were linked to reduced risk of type 2 diabetes.

Egg consumption may reduce the risk of type 2 diabetes, according to new research from the University of Eastern Finland.

According to the University of Eastern Finland, which conducted the egg consumption study, type 2 diabetes is becoming increasingly widespread throughout the world. Research has shown that lifestyle habits, such as exercise and nutrition, play a crucial role in the development of the disease. In some studies, high-cholesterol diets have been associated with disturbances in glucose metabolism and risk of type 2 diabetes.

In contrast, in some experimental studies, the consumption of eggs has led to improved glucose balance, among other things. However, there is no experimental data available on the effects of egg consumption on the incidence of type 2 diabetes, the University of Eastern Finland researchers said.

Also, in population-based studies, the association between egg consumption and type 2 diabetes has been investigated only scarcely, and the findings have been inconclusive. Egg consumption has either been associated with an elevated risk, or no association has been found.

For the egg study, the dietary habits of 2,332 men aged between 42 and 60 years were assessed at the baseline of the Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD) at the University of Eastern Finland in 1984-89. During a follow-up of 19.3 years, 432 men were diagnosed with type 2 diabetes.

The study found that egg consumption was associated with a lower risk of type 2 diabetes as well as with lower blood glucose levels. Men who ate approximately four eggs per week had a 37% lower risk of type 2 diabetes than men who only ate approximately one egg per week, the researchers said. This association persisted even after possible confounding factors such as physical activity, body mass index, smoking and consumption of fruits and vegetables were taken into consideration. The consumption of more than four eggs did not bring any significant additional benefits.

A possible explanation is that unlike in many other populations, egg consumption in Finland is not strongly associated with unhealthy lifestyle habits such as smoking, low physical activity or consumption of processed meats, the researchers explained. In addition to cholesterol, eggs contain many beneficial nutrients that can have an effect on, for example, glucose metabolism and low-grade inflammation, and thus lower the risk of type 2 diabetes.

The study also suggests that the overall health effects of foods are difficult to anticipate based on an individual nutrient such as cholesterol alone.

Indeed, instead of focusing on individual nutrients, nutrition research has increasingly focused on the health effects of whole foods and diets over the past few years.

High-fat dairy. In the other study, researchers at Lund University in Sweden determined that consumption of high-fat yogurt and cheese were linked to a reduction in the risk of type 2 diabetes by as much as one-fifth. On the other hand, in this study, high meat consumption was linked to a higher risk.

The Lund researchers said the findings were in line with previous studies of eating habits that indicated a link between high consumption of dairy products and a reduced risk of type 2 diabetes.

However, the new study indicates that it is high-fat dairy products specifically that are associated with reduced risk.

"Those who ate the most high-fat dairy products had a 23% lower risk of developing type 2 diabetes than those who ate the least. High meat consumption was linked to an increased risk of type 2 diabetes regardless of the fat content of the meat," said Ulrika Ericson, who conducted the study.

The researchers studied the eating habits of 27,000 individuals aged 45-74. The participants took part in the Malmo Diet & Cancer study in the early 1990s, in which they provided details of their eating habits. Twenty years later, more than 10% — 2,860 people — had developed type 2 diabetes.

The aim of the study has been to clarify the significance of fat in food for the risk of developing type 2 diabetes. Instead of focusing on the total intake of saturated fat, the researchers looked at different sources of saturated fat.

Both meat and dairy products contain saturated fat, but certain saturated fatty acids are particularly common in dairy products, Ericson said. This difference could be one of the reasons why most studies show that those who eat meat are at higher risk of type 2 diabetes, whereas those who eat a lot of dairy products appear to have a lower risk.

"When we investigated the consumption of saturated fatty acids that are slightly more common in dairy products than in meat, we observed a link with a reduced risk of type 2 diabetes. However, we have not ruled out the possibility that other components of dairy products such as yogurt and cheese may have contributed to our results. We have taken into account many dietary and lifestyle factors in our analysis, such as fermentation, calcium, vitamin D and physical activity," Ericson said. "However, there may be other factors that we have not been able to measure that are shared by those who eat large quantities of high-fat dairy products. Moreover, different food components can interact with each other. For example, in one study, saturated fat in cheese appeared to have less of a cholesterol-raising effect than saturated fat in butter.

"Our results suggest that we should not focus solely on fat, but rather consider what foods we eat. Many foodstuffs contain different components that are harmful or beneficial to health, and it is the overall balance that is important," she concluded.