A high-glycemic load diet is linked to higher depression symptoms, fatigue and mood disturbance compared to a low-glycemic load diet, a new study finds.
The glycemic load (GL) helps people assess how food portions affect blood sugar levels, and can be useful for people with diabetes who may be unsure about how a meal could affect their management.
Foods with a high GL are those with a high carbohydrate value that influence blood glucose levels quickly. Bread, rice and many breakfast cereals are notable examples of foods with a very high GL.
In this new study, researchers from Fred Hutchinson Cancer Research Centre, Seattle, US examined several hypotheses regarding diet and mood. They also investigated the extent to which carbohydrate intake could affect mood.
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.
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.
Abstract
High Glycemic Index Diet as a Risk Factor for Depression: Analyses from the Women’s Health Initiative
Background: The consumption of sweetened beverages, refined foods, and pastries has been shown to be associated with an increased risk of depression in longitudinal studies. However, any influence that refined carbohydrates has on mood could be commensurate with their proportion in the overall diet; studies are therefore needed that measure overall intakes of carbohydrate and sugar, glycemic index (GI), and glycemic load.
Objective: We hypothesized that higher dietary GI and glycemic load would be associated with greater odds of the prevalence and incidence of depression.
Design: This was a prospective cohort study to investigate the relations 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 3-y follow-up (n = 69,954).
Results: We found a progressively higher dietary GI to be associated with increasing odds of incident depression in fully adjusted models (OR for the fifth vs. first quintile: 1.22; 95% CI: 1.09, 1.37), with the trend being statistically significant (P = 0.0032). Progressively higher consumption of dietary added sugars was also associated with increasing odds of incident depression (OR for the fifth vs. first quintile: 1.23; 95% CI: 1.07, 1.41; P-trend = 0.0029). Higher consumption of lactose, fiber, nonjuice fruit, and vegetables was significantly associated with lower odds of incident depression, and nonwhole/refined grain consumption was associated with increased odds of depression.
Conclusions: The results from this study suggest that 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. The Women’s Health Initiative is registered at clinicaltrials.gov as NCT00000611.
“High Glycemic Index Diet as a Risk Factor for Depression: Analyses from the Women’s Health Initiative” by James E. Gangwisch, Lauren Hale, Lorena Garcia, Dolores Malaspina, Mark G. Opler, Martha E. Payne, Rebecca C. Rossom, and Dorothy Lane in American Journal of Clinical Nutrition. Published online June 24 2015 doi:10.3945/ ajcn.114.103846