It's time to feed your mind

Many of us struggle with our mental health, whether that’s feeling anxious on a regular basis or having a longer-term condition such as depression. There’s so much advice about supporting our mental health, but are we missing a key way to protect our minds?

Chartered psychologist and nutrition expert Kimberley Wilson believes so, arguing that food is an essential piece of the puzzle. Her new book, Unprocessed: How The Food We Eat Is Fuelling Our Mental Health Crisis, explores growing research that suggests what we eat and drink can impact our brain health, which can then influence our mental health. 

‘A resilient brain is one of the main foundations of mental health,’ says Kimberley. ‘And nutrition is a key and undervalued building block.’

Food for thought 

So what have we been getting wrong? As a society, we tend not to think about the role nutrition plays in our mental health. ‘Overwhelmingly, mental health disorders are treated as “mind” problems that are separate from the conditions within the body,’ says Kimberley. ‘When assessing someone for, say, depression, a GP or therapist is more likely to ask about their relationship with their mother than what they eat. But our physical and mental health are the same thing.’

Previously, it was thought that mental ill health could be caused by an imbalance of serotonin in the brain, but Kimberley says: ‘We know that when you add serotonin [in the form of medication], it doesn’t work for as many people as you would expect.’

New research has shifted towards an understanding that the brain is a physical organ like the heart or liver, therefore, mental illness might be linked to a physical complaint in the brain.’ 

Though she doesn’t suggest that nutrition answers every question about the mind and mental health, it is a valuable part of the solution. Here, Kimberley recommends how we can all eat smarter to feel better…

Fill up on fibre 

Only 9 per cent of UK adults aged 19-64 eat the recommended 30g per day of fibre, but what is its connection to mental health? It all starts in the gut. The many species of bacteria in the human gut break down fibre, and, when they do, they produce a range of substances important to our health. These by-products include short-chain fatty acids and neurotransmitters such as ‘happy hormones’ serotonin and dopamine. Fibre also looks after the gut barrier, preventing microbes from crossing into the bloodstream, which could produce an inflammatory response. 

So, a high-fibre diet is ‘neuroprotective’; it looks after our brains. A few tweaks such as replacing cooked white rice with brown, and opting for wholewheat pasta instead of white can dramatically increase your consumption.

Remember, oily fish is your friend 

The brain is one of the fattiest organs in the body, and one particular type of fat is key to its function: omega-3, a long- chain fatty acid. In animals, it has been found that diets deficient in omega-3 change the shape of the hippocampus (the part of the brain associated with learning and memory), suggesting that inadequate levels can make brain function go awry. You can find omega-3 in oily fish and seafood, but most UK adults are consuming one portion of oily fish per month, rather than the recommended 1-2 portions per week. Omega-3 supplements are available, but sardines and tinned salmon are fantastic budget-friendly sources.

Swerve the sweet stuff 

We know too much sugar isn’t great for our physical health, but it can also affect our mental health. Too much for too long can predispose us to insulin insensitivity (meaning insulin is less likely to do its job of removing excess glucose) and high blood sugar (hyperglycaemia). This can damage the cells that line blood vessels, which can carry significant risks of cognitive decline and neurodegeneration.

The good news is we can maintain and even restore insulin sensitivity through dietary management. Adults should have no more than 30g of ‘free sugars’ per day. It’s worth getting to know your food labels: look for the column that reads ‘per 100g’ – a food with 5g or less of total sugars per 100g is considered low in sugar. But it’s okay to eat sweet stuff sometimes – I am a huge fan of home-baking (and was even a finalist on The Great British Bake Off!). I have a batch of cinnamon buns in my freezer, which I defrost when I crave a sweet treat. Home-baked goods are usually high in sugar, but at least you know exactly which ingredients you’re eating.  

4. Beat inflammation 

It could just be a coincidence that rates of mental ill health have been rising at the same time as Western diets becoming reliant on ultra-processed foods (UPFs), but it seems unlikely. UPFs tend to be high in saturated fats, sugars and artificial ingredients, which then strip out vitamins, antioxidants and fibre, displacing nutrients that our bodies and brains need.

Studies have found a significant correlation between UPF consumption and depression risk Diets high in UPFs are generally linked to increased markers of inflammation, and the higher the inflammatory potential of a person’s diet, the worse their brain function tends to be. Studies show more inflammatory diets increase the risk of developing depression. Currently, 55% of UK adults’ calories come from UPFs, so reduce your reliance in your own diet. How? Adopt a Mediterranean-style diet and try beta-carotene-containing coloured vegetables, garlic, ginger, nuts, green and black tea, berries and oily fish.

Dementia diet tweaks 

Once Alzheimer’s Disease (AD) has reached moderate severity, there’s little that can be done to slow its progression. But, says Kimberley, middle age is an important life stage to act on prevention. ‘A third of the modifiable factors  associated with increased risk of AD and dementia are linked to nutrition,’ she says, advising that even after an early diagnosis, what you eat and drink can impact the disease’s progression. Here’s what you need to know:

Supplement with omega-3 

Omega-3’s benefits extend to those suffering with cognitive decline and even early-stage AD. The results of a study on AD and omega-3 indicated that docosahexaenoic acid (a type of omega-3) supplementation in people with very mild, early-stage AD can have a ‘significant protective effect’. 

The must-have mineral 

People with AD have significantly lower levels of magnesium in their cerebral spinal fluid compared to healthy control subjects. Magnesium-rich foods include nuts (especially Brazils), seeds, beans, peas, lentils and – happily – dark chocolate. 

Fill up on greens 

Leafy green veg has been shown to protect brain health for up to 11 years in older people, so try eating a cereal bowl of salad before dinner – think spinach, watercress and rocket.

This piece originally appeared in the April 2023 print edition of Harper's Bazaar UK