Higher dietary intake of animal protein is associated with an elevated risk of type 2 diabetes (T2D), whereas increased consumption of vegetable protein is associated with a slightly reduced risk, a recent study suggests.
The findings suggest that adopting a diet rich in plant-based proteins should be considered for T2D prevention, according to a research team led by Vasanti S. Malik, MD, of the Harvard T.H.Chan School of Public Health in Boston.
Dr Malik and colleagues studied the association between total, animal, and vegetable protein and incident T2D among 72,992 women in the Nurses’ Health Study (1984–2008), 92,088 women in the Nurses’ Health Study II (1991–2009), and 40,722 men in the Health Professionals Follow-up Study (1986–2008). Investigators documented 15,580 new cases of T2D during 4,146,216 person-years of follow-up.
Subjects in the highest quintile of percentage of energy derived from total protein and animal protein had 7% and 13% increased risks of T2D, respectively, compared with those in the lowest quintile, Dr Malik’s team reported online ahead of print in the American Journal of Epidemiology. Subjects in the highest quintile of percentage of energy intake from vegetable protein had a 9% decreased risk of T2D compared with those in the lowest quintile.
The investigators also calculated the effect of substituting 5% of energy from protein for equal exchanges of total and different-quality carbohydrates and substituting vegetable protein for animal protein. Substituting vegetable protein for animal protein was associated with a significant 23% decreased risk. Substituting total and animal protein for total carbohydrate was not associated with T2D risk, but substitution with vegetable protein was associated with a significant 22% decreased risk. Substituting total and animal protein for carbohydrate from whole grains was associated with 20% and 18% increased risks of T2D.
“To our knowledge, this is the first study that has examined long-term intake of protein in relation to T2D risk using repeated measurements taken over many years of follow-up and that has examined the role of substitution of protein and protein type by carbohydrate type in T2D risk,” the authors wrote.