Only recently have scientists begun to explore the relationship between nutrition and mental health. As so far, the study findings are consistent and compelling: what you eat – and don’t eat – can have a powerful impact on mental health.
Our changing diet is thought to contribute to mental health disorders such as depression and anxiety. The transition from a whole foods diet our grandparents ate – one based on nutrient-rich vegetables, fruits and whole grains – to a steady fare of nutrient-poor, high calorie and highly processed foods has been associated with increases in depression and other mental disorders.
Healthy diet patterns protective
Recent studies have connected a “healthy” dietary pattern to a lower risk of depression, anxiety, bipolar disorder and risk of suicide in adults. A 2014 review of 21 studies, for example, concluded that a high intake of fruits, vegetables, fish and whole grains protected against depression.
Researchers have turned up similar findings in children and teenagers. In 2014, a review of seven studies, published in the American Journal of Public Health, revealed a consistent trend between a higher intake of nutrient-dense foods including vegetables, salads, fruits and fish and lower rates of depression, low mood, emotional problems and anxiety. The analysis also found a consistent and positive relationship between an “unhealthy” dietary pattern – a higher intake of saturated fat, sugar, refined starches and processed foods – and poorer mental health in youth.
Research suggests that an unhealthy diet during pregnancy and early childhood, characterized by processed foods, refined cereals, sugary drinks, high calorie snacks and desserts, increases the risk attention problems, aggressive behaviour and anxious and depressive symptoms in children.
How diet may influence depression
Diet is thought to have a direct impact on many biological pathways that underpin depression and other mental health disorders. The anti-inflammatory properties of nutrients in fruits, vegetables, whole grains, nuts and oily fish have been shown to influence concentrations of brain chemicals that regulate emotions and cognition.
Antioxidants including vitamins C and E, beta-carotene and many natural plant compounds may reduce free radical damage to brain cells that influence mental health.
The B vitamin folate is needed for the production of serotonin, a brain chemical (neurotransmitter) responsible for maintaining mood balance. Folate-rich fods include lentils, black beans, cooked spinach, broccoli, asparagus, avocado and artichokes.
A diet based on nutrient-packed whole foods also increases the level of brain-derived neurotrophic factor (BDNF), a protein that improves mood, attention and learning, promotes brain cell growth and lowers brain inflammation. In contrast, a diet high in animal (saturated) fat has been shown to lower BDNF.
Certain foods that feed our so-called “good” gut bacteria, known as prebiotics, may also be linked to better mental health since gut microbes synthesize most of the body’s serotonin. Prebiotic foods include whole grains, artichoke, asparagus, bananas, garlic, onion, chicory root and yogurt.
Science is new, but compelling
The science linking nutrition to mental health is relatively new and much of it is limited to observational studies that don’t prove cause and effect. A randomized controlled study – the gold standard of scientific evidence – is currently underway in Australia to determine if a Mediterranean-like diet can ease depression.
Even so, the current evidence linking nutrition to mental health is so convincing that, in a paper published in The Lancet earlier this year, a panel of international experts suggested that diet is “as important to psychiatry as it is to cardiology, endocrinology and gastroenterology”. It’s time to get back to basics and eat like our grandparents did.
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.