A diet high in refined carbohydrates may lead to an increased risk for new-onset depression in postmenopausal women, according to a study published in The American Journal of Clinical Nutrition.

The study by James Gangwisch, PhD and colleagues in the department of psychiatry at Columbia University Medical Center (CUMC) looked at the dietary glycemic index, glycemic load, types of carbohydrates consumed, and depression in data from more than 70,000 postmenopausal women who participated in the National Institutes of Health's Women's Health Initiative Observational Study between 1994 and 1998.

Consumption of carbohydrates increases blood sugar levels to varying degrees, depending on the type of food ingested. The more highly refined the carbohydrate, the higher its score on the glycemic index (GI) scale. The GI scale, which goes from 0-100, measures the amount of sugar found in the blood after eating. Refined foods such as white bread, white rice, and soda trigger a hormonal response in the body to reduce blood sugar levels. This response may also cause or exacerbate mood changes, fatigue and other symptoms of depression.

The investigators found that progressively higher dietary GI scores and consumption of added sugars and refined grains were associated with increased risk of new-onset depression in post-menopausal women. Greater consumption of dietary fiber, whole grains, vegetables and non-juice fruits was associated with decreased risk. This suggests that dietary interventions could serve as treatments and preventive measures for depression. Further study is needed to examine the potential of this novel option for treatment and prevention, and to see if similar results are found in the broader population.