In this occasional feature, members of the Psych Congress Steering Committee and faculty answer questions asked by attendees at Psych Congress meetings.
QUESTION: Are there benefits to intermittent fasting or a ketogenic diet when treating depression?
ANSWER: There is evidence suggesting that high-fat, high-sugar diets contribute to gut dysbiosis (alterations in the intestinal microbiota) and decreased diversity of gut flora (which under usual circumstances includes more than 1000 different bacterial species). Enteric dysbiosis in individuals suffering from major depressive disorder (MDD) not only contributes to “leaky gut” and elevated peripheral inflammatory signaling, it may aggravate anxiety, depressed mood, irritability, sensitivity to stress, and cognitive problems (including in attention, memory, and executive function). In counterdistinction to studies indicating harmful effects of a “Western diet” on the risk of depression, a large recent meta-analysis found only a minimal increase in risk of future depressive episodes in individuals with poor dietary habits. However, the same study noted a very substantial positive effect of a “good diet” on reducing future depression risk 1.
A number of controlled studies have established benefits of dietary counseling, psycho-biotics (probiotics) and a Mediterranean/anti-inflammatory diet in increasing remission rates, decreasing peripheral inflammatory signals, and improving a range of depressive symptoms—from depressed mood, anhedonia, cognitive difficulties, and irritability to amelioration of hypersomnolence and decreased appetite.
There is a paucity of controlled studies demonstrating antidepressant benefits of caloric restriction. Mostly observational research in non-clinical MDD samples has suggested benefits of caloric restriction and periodic fasting in mood, anxiety, energy levels, sleep, and sexual functioning 2. Other studies have noted only minimal improvement or absence of mood benefits in individuals treated with intermittent fasting and caloric restriction diets.
Without well powered, prospective, controlled, longitudinal studies demonstrating benefits in clinically depressed individuals, it is difficult to endorse caloric restriction diets as a general recommendation for our depressed patients.
—Psych Congress Steering Committee member Vladimir Maletic, MD, MS, Clinical Professor of Psychiatry and Behavioral Science, University of South Carolina School of Medicine, Greenville
1. Molendijk M, Molero P, Ortuno Sanchez-Pedreno F, Van der Does W, Angel Martinez-Gonzalez M. Diet quality and depression risk: a systematic review and dose-response meta-analysis of prospective studies. Journal of Affective Disorders. 2018;226:346-354.
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