The brain as an organ

Although not everyone is trained in nutrition, I can probably safely assume that most of us are aware of the link between what we eat and our physical health. We know that the food we put into our body can impact our fitness, our risk for cardiovascular disease, our bone health and even whether or not we might develop type 2 diabetes or cancer. But, if our food can impact the health of our muscles, our blood vessels and our bones, why not our brain? It’s just another organ, right?

Research over the past few years is indeed showing us that what we eat actually goes far beyond our physical health. One study found that people who ate more fruits and vegetables experienced increased feelings of wellbeing (1). Another study found a reduction in feelings of depression when participants followed a Mediterranean-style diet; this diet is high in fresh plant foods such as fruits, vegetables, nuts, seeds, beans, pulses, whole-grains and unsaturated fats, and low in animal products and processed foods high in fat, sugar and salt. The reduction in depressive symptoms were even sustained 6 months after the intervention finished (2).

Another study, appropriately called the ‘SMILES trial’, was the first randomised control trial (RCT) to confirm that there was a causal link between diet and mental health (3). RCTs are considered the gold-standard research method for establishing cause and effect. In the trial, 67 participants were divided randomly into two groups. One group received dietary recommendations based on the Mediterranean diet, and the other received standard social support. Each group ran for 12 weeks with the same number of visits. At the end of the 12 weeks, 32% of the participants who had changed their diet were no longer considered depressed, compared to only 8% of those receiving social support. This study demonstrated that dietary changes are an important new piece of the puzzle for treatment of mental health disorders, with no nasty side effects and whilst also improving physical health!

How does what you eat impact your brain?

Your gut and your brain are in constant communication with each other. A key aspect of this communication is through our ‘gut microbiota’ – or the bacteria that live in our bowel. What we choose to eat is highly influences the types of bacteria that survive there. Some bacteria are beneficial, producing substances called short chain fatty acids that can support many aspects of our health including appetite regulation, blood sugar control and immunity. Some are harmful and can increase our risk of developing disease. There is some research to suggest that the bugs that live in our gut even have an influence on the types of foods we crave! (4) 

This makes sense when we think back to the foods that made our study participants happier - plant foods. Plant foods contain fibre – a key part of keeping our gut microbiome happy and in balance. A recent study supported this concept when it found that participants with adequate levels of a specific bacterial species were less likely to suffer from depression and had greater chances of a better quality of life (5). The bacterial types linked to improved mental health were known to be ones that thrive on fibre from plants in the diet (6).

The complexity of nutrition & mental health

Humans are complex beings, and the link between diet and mental health is often not straight forward. People living with poorer health, or in more deprived communities, are more at risk of poor mental health and wellbeing. These communities are at a higher risk for poverty and nutritional inadequacy due to reduced access, availability and skill to prepare healthy meals (2). In addition, people experiencing mental health concerns have been found to die 10-25 years earlier than the general population (7). Of course there are a range of factors contributing to this increased risk of mortality, but diet and nutrition is likely to be one of these factors (8). Factors of inequality therefore interact in a complex way with nutrition and mental health.

More plants for mental health

The research we have so far suggests that our diet and lifestyle choices really do have a say in how our brain functions and how well we feel every day. This means we have more control over our mental health than originally thought, which is a powerful concept. Of course not all mental health conditions can be prevented or cured with diet, and what we eat is by no means a silver bullet. But if we can reduce our risk of mental health concerns, whilst also improving our fitness, our heart health, our bone health and our risk for diabetes and cancer PLUS enjoy beautiful and delicious plant-packed meals, why wouldn’t we?

If you have concerns regarding your mental health, always seek professional help from an expert. You could start by visiting your GP, visiting a mental health charity website such as MIND, or finding someone local to you through Hub of Hope.

If you want to make changes to your diet to feel better and receive a FREE 7 day plant-based meal plan, shopping list and all the recipes (plus other freebies), make sure to sign up to my mailing list today and I'll be there to support you on your way!

Don’t forget to smile 

Rosie x 

Hello! I'm Rosie, a vegan and plant-based registered dietitian, I work to support NHS staff with their health, wellness and nutrition, and I am founder of Rosemary Nutrition & Dietetics.

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