Depression and Diet: Does What You Eat Impact Your Mental Health?


Healthy Living - March 28, 2017
David Prescott, PhD - Acadia Hospital 
Depression is estimated to impact more than 350 million people worldwide, and is one of the leading global causes of disability. Psychotherapy and anti-depressant medications have proven to be effective in helping many people with depression, yet these treatments are not universally available, nor universally effective. 

Mental health researchers have started to examine the relationship between diet and depression. Preliminary results suggest that what you eat may be important in maintaining good mental health, and that diet may be a useful addition to standard treatment approaches for depression.

What Types of Food Might be Effective in Reducing Depression?  It should first be emphasized that the state of the research between depression and diet is preliminary. Large studies with proper controls have yet to be performed. However, suggestions from researchers about dietary habits that appear promising in reducing depression include:
  1. Traditional” dietary habits such as Mediterranean, Norwegian, or Japanese:  There is some evidence that these traditional diets, often high in fruits, vegetables, fish, and plant based foods, may be beneficial in combatting depression.  One possible pathway by which these dietary approaches help is that they appear to increase levels of brain derived neurotrophic factor (BDNF), which tends to be low in people with depression.
  2. Increase your consumption of fruits, vegetables, legumes, wholegrain cereals, nuts, and seeds.  Not only may eating these types of foods be helpful in reducing depression in the general population, but some research has suggested that particular groups of people at higher risk for depression, such as people with diabetes, may especially benefit.
  3. Foods high in omega-3 fatty acids:  Fish, such as salmon, light tuna, and sardines, are often identified as good sources of certain healthy types of fatty acids.  People with coronary artery disease, who are also at higher risk for depression, have been identified as a group where eating foods rich in omega-3 fatty acids may improve both physical and mental health.
  4. Limited intake of processed foods, ‘fast’ foods, commercial bakery goods, and sweets:   Several different potential pathways, in the blood, brain, and other physiological systems, have been identified as potentially increasing the risk of depression in people who eat high levels of processed or commercially baked foods.  For example, diets high in these types of foods may lead to immune system responses which are associated with increased levels of depression.
Will Dietary Interventions Replace Psychotherapy or Anti-depressant Medication?  In a word, no, at least not based on current scientific evidence.  However, interventions such as changing typical food choices or increasing moderately vigorous exercise, may be important adjuncts to traditional treatments for depression, which are psychotherapy and anti-depressant medication.

The Mind-Body Interaction: People with chronic illnesses, like cardiovascular disease, diabetes, and others, are at higher statistical risk for being clinically depressed. As with most areas of medicine, scientists and researchers are finding more and more evidence that ‘psychological’ interventions can help with physical illness, and ‘physical’ interventions, like diet, can help with psychological illness. 
The exact mechanisms through which changes in diet might help are not well understood. It could be that improving your diet helps bolster your sense of self-esteem and self-efficacy, both important in combatting depression. Or, certain dietary habits may promote the development of neurotransmitters which are involved in the development of depression. Perhaps healthy diets may reduce the intensity of chronic physical ailments, which are associated with developing depression.
American Psychological Association:  or
National Institute of Health: