The results, published in the American Journal of Clinical Nutrition, contradict several observational studies that indicate that eating dairy products may reduce the risk of developing type 2 diabetes.
Credit: Daryl Lega, National Human Genome Research Institute, National Institutes of Health
SEATTLE – November 16, 2020 – Results of a new trial published by a team led by researchers at the Fred Hutchinson Cancer Research Center suggest that eating lower dairy products may be beneficial for people with metabolic syndrome. In a new study published in The American Journal of Clinical NutritionDr. Mario Kratz, associate professor in the Department of Public Health Sciences at Fred Hatch, led a team that looked at the effect of dairy products on regulating blood sugar levels in people with metabolic syndrome.
This project was driven by previous observational studies indicating that people who ate the most yogurt or full-fat dairy products tended to have a lower risk of developing type 2 diabetes. The results of the new experiment led by Fred Hatch showed that the body’s ability to regulate blood sugar levels was not directly affected by whether participants ate dairy products. However, consuming low-fat or whole milk, yogurt, and cheese reduced insulin sensitivity.
Metabolic syndrome is a group of risk factors that increase your risk of heart disease, diabetes, stroke, and other health problems. Insulin sensitivity refers to how the body’s cells respond to insulin. High insulin sensitivity allows body cells to use blood sugar more effectively, which lowers blood sugar.
The study included 72 male and female volunteers with metabolic syndrome. Using a parallel design, and a randomized controlled trial, the research team randomly divided volunteers into three groups over a 12-week period:
- A dairy-restricted diet that does not contain dairy other than – at most – three servings of skim milk per week
- A low-fat dairy diet, consisting of more than three servings of skim milk, nonfat yogurt and low-fat cheese daily
- A full-fat dairy diet, consisting of more than three servings of whole milk, full-fat yogurt, and full-fat cheese daily
After 12 weeks, Kratz and his research team measured a variety of biomarkers, including blood sugar during glucose tolerance testing, systemic inflammation and liver lipid content. They found that blood sugar regulation was not directly affected by whether participants consumed dairy products. However, participants on the full-fat dairy diet gained modest amount of weight, and participants on both the low-fat and full-fat dairy diets experienced a decrease in insulin sensitivity. Decreased insulin sensitivity can increase the long-term risk of developing type 2 diabetes. However, because blood sugar levels were not affected by dairy foods, the long-term effect of reduced insulin sensitivity in people who eat a diet rich in dairy products on the risk of developing type 2 diabetes is unclear.
“In contrast to previous observational studies that suggested a beneficial relationship between fermented dairy products such as yogurt, as well as high-fat dairy products, and better metabolic health, our rigorous randomized and controlled trial could not confirm that eating more dairy products reduces people’s blood sugar,” he said. Kratz. “While more work needs to be done to examine the effect of diets rich in dairy products on a healthy population, the detection of reduced insulin sensitivity resulting from higher intakes of dairy products may be of concern for people with metabolic syndrome and similar conditions such as prediabetes or prediabetes. Type 2 diabetes. “
Kratz also strongly feels that one study should always be interpreted with caution. First, dairy-rich diets did not reduce insulin sensitivity in all previous trials. Second, it is important to note that although dairy-rich diets reduced insulin sensitivity, this did not lead to elevated blood sugar levels in these participants. Since hypoglycemia is the clinical endpoint that the research team paid the most attention (and was the primary endpoint in this trial), the interpretation of these results is not straightforward. Finally, when evaluating the general health effects of a food group such as dairy products, the effect of food on regulating blood sugar levels is just one of several considerations.
Kratz is a member of the editorial board of the American Journal of Clinical Nutrition. It received funding for this study from several dairy organizations, including the National Dairy Board of the United States and dairy farmers in Canada. Dairy-related funding organizations suggested changes to study design details prior to the study, and some have been implemented. Otherwise, the funding organizations had no influence on the design or conduct of the experiment, or on the analysis and interpretation of the study data.
The research team also received multiple grants from the National Institutes of Health and Department of Veterans Affairs that indirectly supported this project.
At the Fred Hutchinson Cancer Research Center, home to three Nobel Prize winners, multidisciplinary teams of world-renowned scientists are searching for new and innovative ways to prevent, diagnose and treat cancer, HIV / AIDS and other life-threatening diseases. Fred Hitch’s pioneering work in bone marrow transplantation led to the development of immunotherapy, which harnesses the power of the immune system to treat cancer. An independent, non-profit research institute based in Seattle, Fred Hatch houses the nation’s first cancer prevention research program funded by the National Cancer Institute, as well as the Clinical Coordination Center for the COVID-19 Prevention Network and the Women’s Health Initiative.