Researchers from the Harvard School of Public Health have found that women who consume nuts or peanut butter five times per week or more, significantly lowered their risk for type 2 diabetes compared to those who never or rarely ate nuts or peanut butter. The reduced risk was independent of known risk factors for type 2 diabetes, such as body mass index (BMI), family history of diabetes, physical activity, smoking, alcohol use, and dietary factors. The findings appear in the November 27, 2002 issue of the Journal of the American Medical Association.
More than 83,000 women with no history of diabetes, cardiovascular disease, or cancer, from the Brigham and Women’s Hospital based, Nurses’ Health Study, were tracked for 16 years. The study participants were sent food frequency questionnaires on average of every four years between 1980 and 1996 that included information on their nut and peanut butter consumption. The participants also provided information via follow-up questionnaires about family history of diabetes, cigarette smoking, body weight and physical activity. Type 2 diabetes usually occurs after age 40. People with this type of diabetes do not produce adequate amounts of insulin for the needs of the body and/or cannot use insulin effectively.
Women in the study who reported eating nuts at least five times per week reduced their risk of type 2 diabetes by almost 30 percent compared to those who rarely or never ate nuts. The researchers also found that women in the study who frequently ate peanut butter reduced their risk for type 2 diabetes almost 20 percent compared to women in the study who rarely ate peanut butter.
“We were not really surprised by our findings” said Rui Jiang, co-author of the study, and a researcher from the Departments of Nutrition and Epidemiology. “Nuts contain lots of fat, but most fats in nuts are mono- and polyunsaturated fats, which are good for insulin sensitivity and serum cholesterol. Nuts are also rich in antioxidant vitamins, minerals, plant protein and dietary fiber.”
“To avoid increase in caloric intake, people should not simply add nuts on the top of the diet. Instead, people should substitute nuts for less healthy foods such as refined carbohydrates like white bread and red meats.”