Nutritional psychiatry is a rapidly growing ﬁeld of research that has the potential to provide clinically meaningful interventions to both prevent and manage mental illness.
What Is Nutritional Psychiatry?
Researches show that increased consumption of a diet rich in fresh fruits and vegetables has been associated with increased reported happiness and higher levels of mental health and well-being.
Inversely, a reduced likelihood of depression is found to be associated with increased intake of a “healthy diet,” deﬁned as a diet high in fruit, vegetables, ﬁsh and whole grains.
One prominent example of a dietary intervention that affects brain health is the ketogenic diet for children with epilepsy. The reduced epileptic seizures under fasting conditions, when ketone bodies provide the energy for the brain, suggest that an altered energy supply may be instrumental.
Why Are Good Nutrition and Mental Health Associated?
Researchers say the intestinal microbiota may be a key player in the responses to stress and affective disorders, including anxiety, depression and cognition.
In one study, transplantation of microbes from depressed patients into rodents results in depression-related behaviors, and altering gut microbiota through probiotic supplementation or food products influences depression-related behavior in animals.
A high-quality diet may help regulate the gut microbiota and reduce stress and inflammation in the brain, and subsequently maintain proper cognitive function throughout life.
While gut microbiota composition is determined by the host’s genetics and external factors such as lifestyle, the key determinants of gut microbiota composition and function remain diet and nutrition.
What Is a Nutritional Psychiatry Diet?
Nutritional psychiatry diets are characterized by the high intake of vegetables, fruit, whole-grains, nuts, seeds and ﬁsh, with limited processed foods.
In contrast, unhealthy diets high in processed, high-fat, high-sugar foods in adolescence and adulthood are shown to be positively associated with the common mental disorders, depression and anxiety.
However, there is still substantial heterogeneity in defining a healthy diet, as many unique cultures have diverse but still healthy dietary patterns. At the core of these diets are nutrient-dense plant foods and high-quality sources of protein, which are likely to be a significant contributor to the observed results.
Will There Be a Psychiatric Nutrition Therapy?
Although observational research has demonstrated a consistent relationship between diet quality and common mental illnesses, there have been few randomized controlled trials to date, especially in clinical groups. In other words, researchers have not yet found a strong causal relationship to determine how these effects come about.
Moreover, most studies to date have examined the association between diet and depression, with only a limited exploration of anxiety and more severe mental illnesses, such as schizophrenia and bipolar disorder.
Roger A.H. Adana, Eline M. van der Beekc, Jan K. Buitelaare, John F. Cryang, Johannes Hebebrandh, Suzanne Higgs, Harriet Schellekensg, Suzanne L. Dickson. 2019. “Nutritional psychiatry: Towards improving mental health by what you eat.” In European Neuropsychopharmacology, 29, 1321–1332.
Wolfgang Marx, Genevieve Moseley, Michael Berk, and Felice Jacka. 2017. “Nutritional psychiatry: the present state of the evidence.” In Proceedings of the Nutrition Society, 76, 427–436.