High nut consumption may reduce risk of diabetesBMJ 2002; 325 doi: http://dx.doi.org/10.1136/bmj.325.7376.1322/a (Published 07 December 2002) Cite this as: BMJ 2002;325:1322
Women who increase their consumption of nuts and peanut butter may gain some protection against the development of type 2 diabetes, a new study has suggested (JAMA 2002;288: 2554-60)
The researchers, led by Drs Rui Jiang, Frank Hu, Meir Stampfer, and JoAnn Manson from the Departments of Medicine and Public Health at Harvard University School of Medicine in Boston and Cambridge, Massachusetts, conducted a prospective cohort study to examine the effect of nut consumption on the incidence of type 2 diabetes.
The study followed 83818 women from 11 states who were enrolled in the nurses health study, a longitudinal healthcare survey that collects epidemiological data and lifestyle information.
The women in the cohort were aged 34-59 at the start of the study and had no history of diabetes, cancer, or cardiovascular disease at that time. Follow up continued for 16 years.
Diets were assessed from a food frequency questionnaire, which was administered in 1980, 1984, 1986, 1990, and 1994.
Data on peanuts and peanut butter were collected even though peanuts are actually legumes (members of the pea family). From 1986 data were divided into peanuts and other nuts.
Overall, 3206 new cases of diabetes were documented. After body mass index, physical activity, smoking, alcohol, and total energy intake were controlled for, nut consumption was inversely associated with the development of diabetes. Women who ate ≥140 g of nuts a week were 27% less likely to develop diabetes than those who reported rarely or never eating them. Those who ate nuts four times a week reduced their risk by 16%
Compared with women who ate nuts never or almost never (the reference group), the relative risk for those eating a 28 g portion of nuts less than once a week was 0.92 (95% confidence interval 0.85 to 1.00), for those eating a portion 1-4 times a week was 0.84 (0.76 to 0.93), and for those eating a portion five or more times a week was 0.73 (0.60 to 0.89) (P for trend <0.001).
Peanut butter consumption also reduced diabetic risk.