VALLEY — A recent study published in the British Journal of Nutrition reported that higher plant protein intake is associated with a reduced risk of type 2 diabetes. In their analysis, they estimated that replacing one percent of calories from animal protein with calories from plant protein would decrease the risk of type 2 diabetes by 18 percent.
At first glance, it may seem like the dietary effects on diabetes would be only relevant to carbohydrate-containing foods. The more low-carbohydrate, high-protein foods in your diet, the better; those foods don’t directly raise blood glucose. However, that is a too simplistic view of the development of type 2 diabetes. Type 2 diabetes is not only driven by elevated glucose levels, but also by chronic inflammation, oxidative stress, and alterations in circulating lipids (fats).
There has been considerable amount of evidence that red and processed meats are linked to a greater risk of type 2 diabetes, and many studies have compared plant and animal protein intake with respect to diabetes risk. A larger study published in 2016 found an increase in type 2 diabetes risk in those with the highest animal protein intake. They also performed a meta-analysis of 11 previous studies, which detected a 19 percent increase in risk with the highest animal protein intake.
A 2010 meta-analysis of 12 prospective cohort studies concluded that high total meat intake increased type 2 diabetes risk 17 percent above low intake, high red meat intake by 21 percent, and high processed meat intake by 41 percent. Since these foods don’t directly cause an increase in blood glucose, how might they raise diabetes risk?
AGEs are substances that cause oxidative stress and inflammation, damage body proteins and fats, and contribute to heart disease, type 2 diabetes, and complications of diabetes. AGE production in the body is increased by elevated blood glucose. Food is also a source of AGEs, in particular, fried foods, broiled meats, high-fat animal foods, and dry cooked starchy foods (cookies, muffins, cold cereals, fried potatoes). Compared to meats, plant protein sources like beans and raw nuts and seeds afford lower exposure to AGEs.
Too much iron increases the risk for type 2 diabetes. Heme iron, found only in animal products, is highly absorbable compared to nonheme iron in plant foods. A diet high in animal products over time results in excess body stores of iron. A major connection between high heme iron intake and diabetes is that iron in excess has pro-oxidant properties; this can contribute to oxidative damage to pancreatic beta cells and insulin resistance. High dietary heme iron and high body stores of iron are associated with increased risk of type 2 diabetes. Nonheme iron (from plant foods) does not carry the same risk of excess because of its lower absorbability.
The types of fats we eat also affect insulin signaling and therefore diabetes risk. Clinical trials have shown that altering dietary fatty acids can alter insulin sensitivity. In these trials, saturated fats decreased insulin sensitivity, and monounsaturated fats and omega-3 fats either improved or did not affect insulin sensitivity. Animal protein and plant protein are indicators of animal foods and plant foods. Some will be lower or higher in fat, but animal foods generally have a greater ratio of saturated to unsaturated fats, suggesting that high animal food intake could negatively affect insulin sensitivity.
There are many negatives to animal foods when it comes to diabetes risk. However, it’s not simply an issue of avoiding meat; which plant foods you eat matters. A large analysis of the Nurses’ Health Study and Health Professionals Follow-Up Study (including over 200,000 participants) scored the participants’ diets based on a “healthful plant-based diet index,” in which foods like vegetables, legumes, fruits, nuts, and whole grains increased the score and foods like fruit juices, sweetened beverages, refined grains, potatoes, sweets, and animal foods decreased the score.
They also constructed an unhealthful plant-based diet index (uPDI), in which unhealthful plant foods increased the score, and healthful plant foods and animal foods decreased the score. The hPDI was strongly negatively associated with type 2 diabetes, meaning the healthful plant-based dieters had a lower incidence of type 2 diabetes. The uPDI was positively associated with type 2 diabetes, meaning that a diet with a lot of fruit juices, sweetened beverages, refined grains, potatoes, and sweets – even if low in animal foods – increased risk.
High fiber, micronutrient, and phytochemical intake helps prevent or reverse type 2 diabetes. A healthy diet must be composed mostly of whole, fiber-rich, high-nutrient plant foods. It’s not enough to eat a vegan diet or eat only a small amount of animal products. My decades of experience caring for people with type 2 diabetes has enabled over 90 percent of them to become non-diabetic; this has been documented in medical publications. In a study of patients with type 2 diabetes following a NDPR (Nutritarian) diet, after one year 90 percent of participants were able to eliminate all of their diabetes medications, and the average HbA1c was lowered into the normal (non-diabetic) range.
Every physician caring for patients with diabetes and pre-diabetes, as well as patients themselves must be informed about this life-saving approach, as described in my book The End of Diabetes. Type 2 diabetes is reversible in the vast majority of cases, and those with type 1 diabetes can improve their life expectancy, health and quality of life.
Dr. Fuhrman is a #1 New York Times best-selling author and a board certified family physician specializing in lifestyle and nutritional medicine. The Eat To Live Cookbook offers over 200 unique disease-fighting delicious recipes and his newest book, The End of Heart Disease, offers a detailed plan to prevent and reverse heart disease using a nutrient-dense, plant-rich (NDPR) eating style. Visit his informative website at DrFuhrman.com. Submit your questions and comments about this column directly to [email protected]