Health & Nutrition Corner: Plant protein lowers risk of type 2 diabetes

By Dr. Andrew Craig, American Peanut Council

Not all proteins are equal when it comes to their effects on our risk of developing type 2 diabetes (T2D). Plant proteins, including those from peanuts and peanut butter, were found to have a risk-lowering effect compared to other animal protein sources – namely red and processed meats – in a recent prospective epidemiological study from Harvard School of Public Health, supported by the US National Institutes of Health.

To look at the effect of the type of protein consumed, results were adjusted to take into account confounding factors of age and lifestyle. Doing this revealed that a higher intake of energy from protein was associated with a higher risk of type 2 diabetes, but with two important qualifications:


  • This association with type 2 diabetes was stronger with animal protein than those observed for all protein sources.
  • The percentage of energy from vegetable, or plant-based, protein was associated with a decreased risk of type 2 diabetes. Researchers note that “whole grains and peanuts and peanut butter were most commonly consumed sources of vegetable protein”.


The study also investigated the association between substituting a serving of plant-based protein (legumes, peanuts, peanut butter, nuts, whole grains) for a serving of animal protein, refined grains and potatoes. The findings?


  • Substituting 5% of energy intake from total and animal protein for an equal amount of total carbohydrates was not associated with risk of type 2 diabetes. However, substituting with plant-based protein was associated with reduced risk.
  • Substituting vegetable protein for animal protein was associated with a 23% reduced risk of type 2 diabetes. Further, substituting one serving per day of plant protein for an equal amount of animal-based protein, refined grains or potatoes was associated with reduced type 2 diabetes risk, ranging from 6% (from refined grains) to 21% (from processed meat).


These substitution benefits of plant protein for animal protein are impressive in public health terms. Peanuts and peanut butter clearly fit the substitution pattern. It is important to appreciate that these findings are observational and not cause and effect. Nonetheless, the association with reduced T2D risk is strong given the size of the study. As the investigators concluded: “These data suggest that adopting a diet rich in plant-based proteins should be considered for type 2 diabetes prevention.” Substituting peanut and peanut butter for processed animal proteins is an attractive, inexpensive and easily implemented way to achieve this objective.


Source: Malik, VS et al 2016. “Dietary Protein Intake and Risk of Type 2 Diabetes in US Men and Women” American Journal of Epidemiology