Improving mental health by what you eat.

Does it matter what we eat for our mental health? Accumulating data suggests that this may indeed be the case and that diet and nutrition are not only critical for human physiology and body composition, but also have significant effects on mood and mental wellbeing.

While the determining factors of mental health are complex, increasing evidence indicates a strong association between a poor diet and the exacerbation of mood disorders, including anxiety and depression, as well as other neuropsychiatric conditions.

One of the intervention studies performed to date, involved a 12 week Mediterranean diet. Significant improvements in mood and reduced anxiety levels in adults with major depression were reported (Jacka et al., 2018, 2017). Higher serum vitamin D concentrations have been associated with better attention and working memory performance in community-dwelling older adults, aged 65 years and older (Brouwer-Brolsma et al., 2015) More and more related studies have spawned a new discipline—nutrition psychiatry is becoming a research hotspot.

What is Nutritional psychiatry?

Nutritional psychiatry is a growing discipline that focuses on the use of food and supplements to provide these essential nutrients as part of an integrated or alternative treatment for mental health disorders. With the establishment of the International Society for Nutritional Psychiatry (ISNPR) in 2016, more and more studies have jointly promoted the rapid development of area of nutritional mental health, provided clinically meaningful interventions for the prevention and management of mental illness.

Observational studies suggest a continuous relationship between diet quality and mental health, biological pathways including inflammation, oxidative stress, gastrointestinal microbiota, and neurotrophic factors may be the effect mechanism of diet on mental health. Preliminary clinical evidence supports the feasibility and effectiveness of diet and nutrition interventions.

Eating high-quality foods that contain lots of vitamins, minerals, and antioxidants nourishes the brain and protects it from oxidative stress — the “waste” (free radicals) produced when the body uses oxygen, which can damage cells. Otherwise,  your brain can be damaged. Multiple studies have found a correlation between a diet high in refined sugars and impaired brain function(and even a worsening of symptoms of mood disorders), such as depression. In addition to worsening your body’s regulation of insulin, they also promote inflammation and oxidative stress.

A systematic review combining a total of 20 longitudinal and 21 cross-sectional studies, provided compelling evidence that a Mediterranean diet can confer a protective effect against depression (Lassale et al., 2018). In addition, a meta-analysis of 16 randomized controlled trials also indicated that dietary interventions hold promise to reduce depression incidence (Firth et al., 2019). Together, these studies provide a reasonable evidence base to further investigate the effect of specific dietary interventions on mental health.

Along with dietary intake, nutrition can also be obtained from “nutrient supplements”, such as polyunsaturated fatty acids (PUFAs), vitamins, minerals, antioxidants, amino acids and pre/probiotic supplements. Recently, a large number of meta‐analyses have proved the effectiveness of nutrient supplements in the treatment of mental disorders. In 2019, a meta-analysis of randomized double-blind controlled studies conducted by scholars from the University of Western Sydney, Australia and the University of Manchester, UK, was published in the journal World Psychiatry, the strongest evidence was found for PUFAs (particularly as eicosapentaenoic acid) as an adjunctive treatment for depression. More nascent evidence suggested that PUFAs may also be beneficial for attention-deficit/hyperactivity disorder, whereas there was no evidence for schizophrenia. Folate-based supplements were widely researched as adjunctive treatments for depression and schizophrenia, with positive effects from RCTs of high-dose methylfolate in major depressive disorder. There was emergent evidence for N-acetylcysteine as a useful adjunctive treatment in mood disorders and schizophrenia. What is important is all nutrient supplements had good safety profiles, with no evidence of serious adverse effects.

The adult brain requires a disproportionately large energy supply, while it represents about 2% of body weight, it consumes about 20% of whole body energy requirements. This means your brain requires a constant supply of fuel. That “fuel” comes from the foods you eat. Put simply, what you eat directly affects the structure and function of your brain and, ultimately, your mood. Like an expensive car, your brain functions best when it gets only premium fuel.

Reference：

1. Roger A.H. Adan, Eline M. van der Beek et al. Nutritional psychiatry: Towards improving mental health by what you eat. European Neuropsychopharmacology (2019) 000, 1–12
2. Joseph Firth, Scott B.Teasdale. et al. The efficacy and safety of nutrient supplements in the treatment of mental disorders: a meta-review of meta-analyses of randomized controlled trials. World Psychiatry 2019;18:308–324.