Dairy products may help prevent type 2 diabetes (T2D), but red and processed meat increase the risk

According to the CDC, type 2 diabetes accounts for 90-95% of all diagnosed diabetes cases.

A new meta-analysis links low-fat dairy products to a lower risk of developing type 2 diabetes.

The study linked red and processed meats to an increased risk of T2D, while fish and eggs were found to be suitable protein alternatives.

According to other experts, T2D may be reversible through dietary and lifestyle changes.

According to the Centers for Disease Control and Prevention (CDC), one out of every ten people — 37 million Americans — has diabetes, and one out of every three has prediabetes.

Type 2 diabetes (T2D), the most common type of diabetes, occurs when the body becomes resistant to the insulin produced by the pancreas or when the pancreas fails to produce enough insulin. Insulin is a hormone that controls blood sugar levels.

Diabetes raises the risk of health complications such as cardiovascular disease, kidney failure, stroke, blindness, and circulatory problems, which may necessitate amputation of toes, feet, or a portion of the leg.

Researchers from the University of Naples Federico II in Naples, Italy, have gathered evidence that certain foods can reduce the risk of T2D onset in a new study.

Annalisa Giosuè, Ph.D., of the institution's Department of Clinical Medicine, led an extensive investigation into the relationship between various animal-based foods and the condition.

Most animal products should be consumed in moderation according to current T2D prevention dietary guidelines.

However, research indicates that certain animal products may have health benefits in terms of lowering T2D risk.

Type 2 diabetes is one of the leading causes of death from diet-related causes worldwide. Dr. Giosuè said, "Learning more about how different dietary components increase or decrease the risk of type 2 diabetes is critical to its prevention."

To that end, Giosuè and colleagues examined 13 previously published meta-analyses that investigated which foods were associated with an increased risk of T2D.

They claimed that this type of "review of reviews" assembles one of the most comprehensive levels of evidence available in medical research.

Which meats contribute to T2D?

The 13 meta-analyses provided estimates of how 12 different animal-based foods may increase or decrease the risk of developing T2D. Among the categories are:

total meat, red meat, white meat, processed meat, total dairy, full-fat dairy, low-fat dairy, fish milk, cheese, yogurt, and eggs

A daily intake of 100 grams (3.53 ounces) of total meat was linked to a 20% increase in risk. A 22% increase in risk was linked to the same amount of red meat.

Half that amount of processed meats, such as deli meat, bacon, and sausages, could be responsible for a 30% increase in T2D risk.

Meat, particularly red and processed meats, is a significant source of saturated fatty acids, cholesterol, advanced [glycation end] products, and heme [animal-derived] iron, all of which are known to promote chronic subclinical inflammation and impair insulin sensitivity — the ability of cells to properly respond to insulin stimulation by absorbing glucose from the blood, lowering glycemic levels.

Sodium, nitrates, and nitrites in processed meats may "not only damage insulin-producing pancreatic cells but also induce oxidative stress and vascular dysfunction, which, in turn, [reduce] the cells' sensitivity to insulin," according to Dr. Giosuè.

However, 50 g (1.76 oz) of white meat, which includes chicken and turkey, was associated with only a 4% increased risk of T2D.

Dr. Giosuè believes this is due to the fact that this meat contains less fat, a healthier fatty acid profile, and less iron from animals.

The protective properties of dairy foods

Dr. Giosuè and her colleagues discovered that dairy foods may protect against T2D or have no effect on its onset.

Consuming 200 g (almost 1 cup) of milk was linked to a 10% lower risk of T2D, while 100 g (3.52 oz) of yogurt was linked to a 6% risk reduction.

A cup of total dairy and a cup of low-fat dairy was linked to a 5% and 3% reduction in T2D risk, respectively.s

The meta-analyses, on the other hand, revealed that cheese and full-fat dairy had no effect on T2D risk. However, the evidence was of low to moderate quality.

Dr. Giosuè mentioned several benefits of eating dairy products on a regular basis.

"Dairy products are a source of nutrients, vitamins, and other components (such as calcium, proteins, peptides, and so on) that may have a beneficial effect on glucose metabolism. Whey protein in milk, for example, has a well-known effect on modulating the rise of glucose blood levels after meals, as well as on appetite and body weight control."

"Probiotics, which can be found in yogurt, the other dairy item whose consumption is associated with a lower risk of type 2 diabetes," she continued.

Other low-quality evidence suggested that neither daily 100-gram servings of fish nor one egg per day have a significant impact on T2D risk.

Diabetes management through diet

The current study lends support to the idea that limiting or avoiding animal-based foods, specifically red and processed meat, can help prevent T2D.

"Our findings on the most appropriate intake of animal foods to prevent type 2 diabetes incidence are highly concordant with the characteristics of the Mediterranean diet, which is the plant-based dietary pattern that has more consistently demonstrated over time the potential to reduce the risk of type 2 diabetes and cardiovascular diseases."

Dr. Roy Taylor, a physician, author, professor, and director of the Newcastle Magnetic Resonance Centre at Newcastle University in the United Kingdom who was not involved in the current study, argued in a September 2022 podcast that the widespread availability of "cheaper" and more easily accessible processed foods is to blame for the rise in T2D cases.

He was particularly concerned about the rise in cases among children.

According to the American Diabetes Association, T2D is a chronic condition, but there is evidence that it may be reversible through dietary and lifestyle changes.

Numerous studies, including this one from 2022, have found a link between eating ultra-processed foods and an increased risk of T2D. Other studies have found that interventions such as a low-calorie diet, physical activity, or bariatric surgery can help reverse T2D.

While more research is needed to determine whether a mostly plant-based diet, such as the Mediterranean diet, can reverse T2D, a growing body of evidence suggests that it can help prevent or delay the progression of the condition.

Call for more evidence

The Italian researchers admitted that some of the data in the 13 meta-analyses were of poor quality. As a result, they are hesitant to make "firm recommendations" for T2D prevention based on their current research.

Nonetheless, Dr. Giosuè stated, "Our study adds to the belief that a plant-based dietary pattern including limited intakes of meat, moderate intakes of fish, eggs, and full-fat dairy, and habitual consumption of yogurt, milk, or low-fat dairy may represent the most feasible, sustainable, and definitely successful population strategy to optimize the prevention of type 2 diabetes."