More Protein, More Diabetes

Dietary protein intake and incidence of type 2 diabetes in Europe: The EPIC-INTERACT Case-Cohort Study. By van Nielen and colleagues. Diabetes Care, published online April 10, 2014

What is the problem and what is known about it so far?

People at risk for type 2 diabetes can lower their chances of developing the disease by making lifestyle changes, such as increasing physical activity and improving eating habits. Protein is an essential nutrient, but research is mixed regarding how much and what kind of protein is ideal. Some evidence suggests that high-protein diets may help keep blood glucose in a normal range, while other research indicates that too much protein is a risk factor for type 2 diabetes.

Why did the researchers do this particular study?

Researchers wanted to explore how the amount and source of dietary protein affect risk for developing type 2 diabetes.

Who was studied?

The study included 12,403 people who developed type 2 diabetes during a 12-year study period and 16,154 participants without the disease from eight European countries.

How was the study done?

Participants who did not have diabetes at the study's start filled out surveys about their eating habits 12 months before enrollment in the study. Researchers noted the participants’ protein intake and then tracked their diabetes status over the next 12 years. They used a statistical analysis to determine whether protein intake was linked to type 2 diabetes risk.

What did the researchers find?

Among diets with the same number of calories, women, particularly obese women, with a higher total protein intake or a higher animal protein intake were at a greater risk for developing type 2 diabetes than those who ate less protein or who got their protein from mostly plant sources. The risk of developing type 2 diabetes increased 6% for every 10 gram (0.35 ounces) increase in total protein intake—equivalent to a glass of milk or a 1.75 ounce piece of chicken or beef.

What were the limitations of the study?

The study cannot prove that eating more protein causes type 2 diabetes.

What are the implications of the study?

Limiting protein from animal sources may help women lower their risk for developing type 2 diabetes.

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