Nut and Peanut Butter Consumption and Risk of Type 2 Diabetes in Women - Nut and Peanut Butter Consumption and Risk of Type 2 Diabetes in Women
The goal of this study was to assess whether nut and peanut better consumption reduces the risk of diabetes. Nuts are high in fiber and unsaturated fatty acids (PUFA's and MUFA's), which may benefit carbohydrate metabolism by improving insulin sensitivity.
Patients Screened: 83818
Reporting of Type 2 diabetes at Follow-Up
Women enrolled in the Nurses' Health Study since 1976 underwent a diet assessment every 4 years from 1980 to 1994. Nut consumption was estimated from the frequency of a serving size of 1 oz from never with nine gradations to more than 6 times a day. Peanuts (botanically classified as legumes) were considered together with other nuts, and peanut butter was estimated as frequency of tablespoons. 83,818 women were available for analysis after exclusions for diabetes, CVD, cancer, and extremes of caloric consumption. Information was available on family history of diabetes, body weight, physical activity, and other risk factors. The primary outcome was the reporting of type 2 diabetes at follow-up, which was then validated by classic criteria.
At baseline 35% of women reported almost never consuming nuts, 36% less than once/week, 24% 1-4 times/week, and 5% at least 5 times/week. Women consuming nuts generally weighed less, were less likely to smoke, and more likely to exercise. Nut consumption was inversely associated with glycemic load and intake of trans-fats. 3,206 cases of type 2 diabetes occurred in over 1.2 million person-years follow-up from 1980 to 1996. The age adjusted RR of diabetes was 0.55 for women who ate nuts at least 5 times/week compared to almost never. RR was reduced to 0.74 after BMI was added to the model. When nut consumption was in the model RR was unchanged after further control for family history, physical activity, smoking, alcohol use, total caloric intake, or other dietary variables including glycemic load, other sources of fat, grains, and fish. The RR for peanut butter 5 times/week vs. almost never was 0.79. There was no relationship between nute consumption and weight gain.
Among women enrolled, higher nut and peanut butter consumption was associated with a lower incidence of type 2 diabetes. To avoid increasing caloric intake, regular nut consumption can be recommended as a replacement for refined grains and red or processed meat. It has been speculated that the specific fatty acid composition of the phospholipids in skeletal muscle is related to insulin sensitivity, something akin to omega-3-fatty acids (PUFA's) reducing myocardial cell excitability and sudden death. The high fiber and fat content of nuts may provide satiety and reduce intake of foods with a high glycemic index.
Jiang R, Manson JE, Stampfer MJ, et al. Nut and Peanut Butter Consumption and Risk of Type 2 Diabetes in Women. JAMA. November 27, 2002;288:2554-2560.
Keywords: Neoplasms, Follow-Up Studies, Muscle, Skeletal, Body Weight, Diabetes Mellitus, Type 2, Death, Sudden, Glycemic Index, Risk Factors, Insulin Resistance, Weight Gain, Smoking, Body Mass Index, Carbohydrate Metabolism, Fatty Acids, Omega-3, Blood Glucose, Motor Activity, Energy Intake, Phospholipids
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