Of our many modern diseases, one of the biggest burdens on society is depression according to the World Health Organization. And what we eat may be contributing, finds a new study published in the American Journal of Clinical Nutrition .
James E. Gangwisch, PhD, assistant professor at Columbia University in the department of psychiatry, wanted to find out whether foods with a higher glycaemic index (GI) would be associated with greater odds of depression. He and a team of researchers looked at data from food questionnaires and a scale that measures symptoms of depressive disorders from postmenopausal women in the Women’s Health Initiative Observational Study. The data came from roughly 70,000 women, none of whom suffered from depression at the study’s start, who had baseline measurements taken between 1994 and 1998, and then again after a three-year follow-up.
The results showed that a progressively higher dietary GI was associated with increasing odds of the incident of depression. Consumption of foods higher on the glycaemic index, including those rich in non-whole/refined grains and added sugar, were associated with greater odds of depression, the researchers found. Whilst some carbohydrate foods were significantly associated with lower odds against developing depression, including fibre, whole grains, whole fruits, vegetables and lactose that sit lower on the glycaemic index.
Though the authors couldn’t pinpoint a mechanism from this study—it was associative—they note that one possibility is that the overconsumption of sugars and refined starches is a risk factor for inflammation and cardiovascular disease, both of which have been linked to the development of depression. This kind of diet could also lead insulin resistance, which has been linked to cognitive deficits similar to those found in people with major depression.
Further research is needed, Gangwisch says, and it’s not yet known whether the results would translate to a broader group of people, including men and younger women.