A diet rich in low-fat dairy products appears to lower the risk of developing type 2 diabetes, but a diet high in red meat and processed meats raises that risk, according to a study recently presented at the European Association for the Study of Diabetes (EASD) 2022 Annual Meeting.
The team of researchers, who were from Federico II University in Naples, Italy, did what’s called an “umbrella review,” which is essentially a review of existing reviews in that it collects all the published evidence on a subject and gives it a high-level overview. In all, 13 meta-analyses were included in the study, and they provided what the authors termed 175 “summary risk ratios.” The researchers were especially interested in animal-based foods because their relationship to diabetes had been inadequately studied.
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The survey concentrated on the effects of total meat, red meat, white meat, processed meats, fish, total dairy, full-fat dairy, low-fat dairy, milk, cheese, yogurt, and eggs. As far as the authors were aware, their study was the first wide-ranging survey of the data on the relationship of animal-derived foods to the risk of type 2 diabetes. According to lead author Annalisa Giosuè, MD, “The existing evidence and dietary recommendations for Type 2 diabetes prevention are mainly based on the appropriate consumption of plant foods: high amounts of the fiber-rich ones and low consumption of the refined ones as well as those rich in free sugars. And also on the adequate choice among fat sources — reduction of saturated fat sources like butter and cream and replacement with plant-based poly- and monounsaturated fat sources like nontropical vegetable oils. But not on the most suitable choices among different animal foods for the prevention of Type 2 diabetes.”
Red meat linked to higher type 2 risk, dairy linked to lower risk
The authors concluded that eating 100 grams (about 3 1/2 ounces) per day of total or red meat, or 50 grams per day of processed meat, was associated with an increased risk of type 2 diabetes. They also reported an increased risk with white meat, but the risk was, as they put it, “borderline.” With dairy foods, however, the risk reports were completely opposite. They found that certain foods lowered the risk of type 2 diabetes, namely total dairy (a 5% reduction), low-fat dairy (4% reduction), milk (10% reduction), and yogurt (6% reduction). Insignificant effects were found for 200 grams per day of full-fat dairy, for 30 grams per day of cheese, and for one egg per day. The researchers were mildly surprised that fish consumption had a neutral association with type 2 diabetes risk (1.04% reduction for 100 grams per day) as did one egg per day (1.07% reduction), but evidence quality was low. According to session moderator Matthias Schulze, MD, of the German Institute of Human Nutrition in Berlin, “Fish is more clearly related to reduced cardiovascular risk than for preventing Type 2 diabetes, where we’ve had mixed results. They might not always be the same.”
The researchers had no clear-cut explanations for their findings, but Dr. Giosuè pointed out that dairy products contain several nutrients, vitamins, and other components, such as calcium and vitamin D, that have positive effects on glucose metabolism. “Whey proteins in milk,” she said, “have a well-known beneficial effect on the regulation of the rise of glucose levels in the blood after meals, and also on the control of appetite and body weight.” At the same time, meat contains
cholesterol, saturated fatty acids, and heme iron, which can affect insulin sensitivity, Giosuè explained, while “processed meats also contain nitrates, nitrites, and sodium that can contribute to pancreatic cell damage and vascular dysfunction, thus affecting insulin sensitivity.”
The researchers summed up their findings by writing, “To reduce diabetes risk the consumption of red and processed meat should be restricted; a moderate consumption of dairy foods, milk, and yogurt can be encouraged; moderate amounts of fish and eggs are allowed.”