Walnuts are rich in polyunsaturated fatty acids and have been shown to improve various cardiometabolic risk factors.This trial investigated association between walnut intake & type 2 diabetes in the Nurses’ Health Study which followed 58,063 women aged 52–77 years old from 1998–2008 and
79,893 women aged 35–52 y in NHS II (1999–2009) without diabetes, cardiovascular disease, or cancer at baseline.
Consumption of walnuts and other nuts was assessed every 4 years using food questionnaires. A total of 5930 new type 2 diabetes cases during 10 y of follow-up were detetected. Walnut consumption was associated with a lower risk of type 2 diabetes for participants consuming 1–3 servings/mo (1 serving = 28 g), 1 serving/wk, and >2 servings/wk of walnuts: were 0.93, 0.81 and 0.67 compared with women who never/rarely consumed walnuts. Further adjustment for updated BMI slightly attenuated the association and the HRs were 0.96, 0.87 & 0.76 , respectively.
The consumption of total nuts and other tree nuts was also inversely associated with risk of type 2 diabetes, and the associations were largely explained by BMI. Our results suggest that higher walnut consumption is associated with a signiﬁcantly lower risk of type 2 diabetes in women.