Drinking sweetened beverages such as sugary sodas, and eating refined foods and pastries has been linked to an increased risk of depression in longitudinal studies. However, studies that measure overall intakes of carbohydrate and sugar, glycemic index (GI) and glycemic load are in need. So researchers from Columbia University set up a prospective cohort study to investigate the relationship between dietary GI, glycemic load and other carbohydrate measures (added sugars, total sugars, glucose, sucrose, lactose, fructose, starch, carbohydrate) and depression in postmenopausal women who participated in the Women’s Health Initiative Observational Study at baseline between 1994 and 1998 (n=87,618) and at the three-year follow-up (n=69,954) (Am J Clin Nutr. June 24, 2015).

The researchers found a progressively higher dietary GI to be associated with increasing odds of incident depression. Progressively higher consumption of dietary added sugars was also associated with increasing odds of incident depression. Higher consumption of lactose, fiber, non-juice fruit and vegetables was significantly associated with lower odds of incident depression, and non-whole/refined grain consumption was associated with increased odds of depression.

The results from this study suggest high-GI diets could be a risk factor for depression in postmenopausal women. Randomized trials should be undertaken to examine the question of whether diets rich in low-GI foods could serve as treatments and primary preventive measures for depression in postmenopausal women.