Eating walnuts may reduce the risk for type 2 diabetes in women, according to a new study in the Journal of Nutrition.Frank B. Hu from Harvard School of Public Health in Boston, MA and colleagues conducted the study and found women eating more than 2 servings per week were 33 percent less likely to develop type 2 diabetes, compared with those never eating walnuts.
Walnuts are high in omega-3 fatty acids, which have been found by other researchers to reduce the risk for insulin resistance, at least in rats. On the other hand, saturated fat and trans fat are known to increase the risk for type 2 diabetes.
Data on incident type 2 diabetes and walnut consumption used in the study came from the Nurses’ Health Study (NHS) which involved 58,063 women aged 52 to 77 years and NHS II which involved 78,893 women aged 35 to 52 years who did not have diabetes, cardiovascular disease or cancer at the start of the studies.
Walnut consumption was estimated based on dietary data collected from participants every four years through a validated food frequency questionnaires. Cases of type 2 diabetes were self-reported and confirmed by another validated questionnaire. During a 10-year follow-up, 5930 incident type 2 diabetes were identified.
Researchers found without adjustment for body mass index, walnut consumption was associated with lower risk of type 2 diabetes, those consuming 1 to 3 servings (one serving = 28 grams), one serving per week and greater than two servings per week were 7%, 19% and 33% less likely to develop type 2 diabetes, respectively, compared with those who never ate walnuts.
After adjustment for BMI, the association was weaker. The reduction in the risk for type 2 diabetes was 4%, 13% and 24% less likely to develop type 2 diabetes, respectively, compared with non-walnut eaters.
Additionally, consumption of total nuts and other tree nuts was also found inversely associated with the risk of type 2 diabetes.
The researchers concluded "Our results suggest that higher walnut consumption is associated with a significantly lower risk of type 2 diabetes in women."
