3 Ways to Eat to Beat the Blues

New research confirms healthier eating can improve symptoms of depression.

Posted Feb 15, 2019

Rawpixel/Pixaby, used with permission
Eat more nutrient-rich foods.
Source: Rawpixel/Pixaby, used with permission

While unhealthy diets are known to have a negative effect on both physical and mental health, the benefits of a healthy diet have only been clearly demonstrated in studies on physical health, until now. Scientists at the University of Manchester, and other European research institutes, performed a meta-analysis, or a complete overview, of all existing research on the topic of diet and mental health. Their goal: To confirm the effects of dietary interventions on mental health, specifically on symptoms of depression and anxiety.

The scientists narrowed their findings down to 16 credible, randomized controlled trials, studies that looked at the mental health outcomes of people who follow what is considered a healthy diet, such as a Mediterranean-style diet, compared to the mental health outcomes of those who don’t follow a healthy diet. Together, these 16 studies collected data from more than 45,000 participants, some with diagnosed depressive disorders but a majority who had symptoms of depression but were undiagnosed.

For the purpose of this analysis, a healthy diet is defined as one that aims to 1) reduce calorie intake for the purpose of losing weight; 2) reduce the amount of unhealthy foods consumed, or; 3) increase the amount of healthy foods consumed. The researchers did not look at studies of individual foods or nutrients, but rather at studies that reported the effects of an overall approach to following a healthy diet. They found that all types of dietary improvements seem to improve mental health and that depressive symptoms improved equally, regardless of whether a dietary intervention was designed to reduce weight, cut out junk food, or introduce more nutrient-rich and otherwise healthy foods into the diet, such as fresh fruits and vegetables and whole grains. 

Several studies included in this analysis found that dietary interventions were more beneficial for women than for men, not only for depressive symptoms but also for symptoms of anxiety. (Overall, however, the effects of dietary changes on anxiety appeared to be minimal.) For both men and women, exercise combined with a healthier diet has shown an even more profound positive affect on symptoms of depression than dietary interventions alone.

Future research will help pinpoint exactly how dietary changes improve mental health and protect against mental illness. Meanwhile, these researchers point out several possibilities, including the power of vitamins, minerals, and other beneficial substances (such as phytochemicals, fiber, and beneficial bacteria) found in abundance in a healthy diet, to reduce inflammation and cellular dysfunction, and prevent disturbances in the gut microbiome, all of which are associated with disturbances in mental health.

References

Firth J, Marx W, Dash, S, Carney R, Teasdale SB, Solmi M et al. The effects of dietary improvement on symptoms depression and anxiety. Psychosomatic Medicine: Journal of Behavioral Medicine. February 5, 2019 published online ahead of print.

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