Consuming a diet high in refined carbohydrates such as white rice, white bread and sugar has been linked to an increased risk for new-onset depression in postmenopausal women, according to new research published in The American Journal of Clinical Nutrition.
These refined carbohydrates trigger a hormonal response that tells the body to reduce blood sugar levels, thereby leading to fatigue, mood changes and depressive symptoms.
The more highly refined a carbohydrate, the higher its score on the glycemic index (GI) scale. The GI scale, which ranges 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, listlessness and other symptoms of depression.
The study, conducted by James Gangwisch, Ph.D., and colleagues in the department of psychiatry at Columbia University Medical Center (CUMC), looked at the data of 70,000 postmenopausal women who had participated in the National Institutes of Health’s Women’s Health Initiative Observational Study between 1994 and 1998.
The researchers analyzed the women’s diets, including the dietary glycemic index of the foods they consumed, their glycemic load and the types of carbohydrates consumed, as well as the depression levels of the women.
Consumption of carbohydrates increases blood sugar levels to varying degrees, depending on the type of food ingested. The researchers found that progressively higher dietary GI scores and consumption of added sugars and refined grains were linked to a greater risk for the development of depression in post-menopausal women.
On the other hand, the researchers found that greater consumption of dietary fiber, whole grains, vegetables and non-juice fruits was associated with a decreased risk of depression. These findings strongly suggest that dietary interventions could serve as treatments and preventive measures for depression.
“The results from this study suggest that high-GI diets could be a risk factor for depression in postmenopausal women,” write the researchers. “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.”
According to the National Institute of Mental Health (NIMH), some symptoms of depression include persistent sad, anxious, or “empty” feelings; feelings of guilt, worthlessness, or helplessness; irritability, restlessness or fatigue; difficulty concentrating; insomnia or excessive sleeping; and thoughts of suicide.