Gym Owner Monthly

Britain is the fast food capital of Europe – and it’s driving a mental health crisis A new book explores the idea that what we eat can impact brain function at every stage of life

What if, instead of starting with your stress levels, work and relationships, a therapist asked you what you had for lunch? 
Nutrition is a “central yet overlooked and ignored underlying factor in our rising rates of mental illness”, says Kimberley Wilson, a clinical psychologist with a degree in nutrition, in her new book, Unprocessed.
There are other factors at play, but what we eat is a crucial ingredient. “The brain is a physical organ… nutrition isn’t the be all or end all, but it’s going to be a contributing factor to how well your brain is functioning,” she says. 
The idea that your diet affects your brain is not ground-breaking. But Wilson argues that what we eat not only has an impact on our mood, but affects our brain function at every stage of life: from before life begins, in pregnancy, to reducing the impact of cognitive decline in old age. 
“The nutrients you ingest influence the structure of your brain, the production of brain chemicals that create your mood, and the speed at which your brain ages,” she writes. “Yet if you go to your doctor for help with a mental-health issue, you’re more likely to be asked about your relationship with your mother than what you had for breakfast.”
Her book includes examples of how this affects brain health throughout life: “If a mother doesn’t eat enough of the right fats during pregnancy, her baby’s brain is smaller and less well connected.” In adulthood: “Just a few days on a diet of high-sugar, high-fat, ultra-processed foods leads to measurable impairment in learning, memory and appetite control.”

Ultra-processed food (UPF) is to blame

Rates of mental illness in the UK have been rising steadily for 30 years. One in six children aged five-16 now have a probable mental-health disorder. Wilson at least partly pins the blame for this on ultra-processed food (UPF). 
“So much of our diet is ultra-processed, but we just consider them normal foods: I think very few people would recognise baby formula or baby rusks as UPF, but by definition, they are,” says Wilson.
In Britain, we buy more UPFs than anywhere else in Europe: 50.7 per cent of our daily intake comes from ultra-processed food. For one in five young people, this figure is 78 per cent.
UPFs are foods that are highly processed and industrially altered with additives and ingredients you wouldn’t find in your own kitchen, like colouring or emulsifiers. They are linked to rising obesity rates, type 2 diabetes and several types of cancer. Research from Imperial College London found that the more UPFs a child eats, the greater their risk of becoming obese and, in adults, UPF consumption is linked with an increased risk of cancer overall, but particularly ovarian and brain cancers.    
Crisps, cakes and fizzy drinks are UPFs, but so are supermarket loaves of bread, breakfast cereals and flavoured yoghurts. 
What impact does this have? UPFs contain less brain-healthy nutrients than whole foods and fewer antioxidants. A diet high in UPFs also displaces key nutrients for brain health. UPFs limit variety: 75 per cent of the processed foods that make up the majority of the average diet in the UK are based on just five animals and 12 products. 
“The convenience of these foods means that they increasingly displace more nutritious but more labour-intensive foods from our diets,” Wilson writes.

Diet and dementia risk

There is clear evidence that a poor diet is linked to an elevated risk of developing dementia or Alzheimer’s disease. In her book, Wilson cites the MIND diet (the Mediterranean-Dash Intervention for Neurodegenerative Delay). 
It was formulated to slow brain ageing: rich in wholegrains, leafy green vegetables, fish, olive oil and fruit, combined with limited consumption of fried or fast food, confectionery, butter and red meat. In a study of 923 older adults, the closer they followed the diet, the lower their risk of developing Alzheimer’s.
Another study found a direct relationship between diet quality and hippocampal size (the brain’s memory centre, which is damaged in Alzheimer’s disease). 
UPFs are typically low in fibre. “It’s really concerning that no one in the UK is meeting fibre recommendations [of 30g a day]” she says. This, in turn, has an impact on brain health. 
“When your gut microbes ferment fibre, they produce short-chain fatty acids. And one of the key functions [of these] is to support the integrity of your blood brain barrier, which is a very selective barrier that prevents neurotoxic compounds from the bloodstream from crossing into the brain,” says Wilson. 
“At least theoretically, if you’re not getting enough fibre, then what you’ve got is the dysfunction in your blood brain barrier… one of the precursors and perhaps a driver of dementia.” 
Sugar is another factor. Too much glucose – for example, from sugars in fizzy drinks and sweet treats – can predispose someone to high blood sugar and insulin insensitivity. 
“One of the big dietary risk factors for dementia is diabetes or prediabetes – we know that increases your risk two- or threefold,” says Wilson. “That’s why concerns about children’s rates of obesity are key – the longer you live with hyperglycemia, the worse your risk of dementia later on.”

Good mood food

There is also a direct link between diet and depression. A paper published in the journal PLOS One in 2019 found that a reduction in processed food intake and an increase in fruit, vegetables, fish and olive oil consumption reduced depression in young adults.
The high-profile SMILEs trial (“supporting the modification of lifestyle in lowered emotional states”) published in 2017 found that, among a group of 67 people with depression and a poor diet, those who switched to a Mediterranean-style diet were four times more likely to recover and also experienced reduced anxiety symptoms. 
“Previous research suggests that improved nutrition could reduce nutritional deficiencies, improve neurotransmitter synthesis and provide [a base] for the gut microbiome, all of which can support brain function,” says Wilson in her book. “Inflammation” has recently become a buzzword for conditions as varied as heart disease, cancer and type 2 diabetes, but it is also thought to play a role in depression. And can be exacerbated by a poor diet. 
“The emerging consensus is that the higher the inflammatory potential of a person’s diet, the worse their brain function will tend to be,” she writes. “A large prospective study, which followed over 26,000 people for an average of five years, found that those with a more pro-inflammatory diet had a greater risk of developing depression.”

Eat yourself happy

Think Mediterranean: lots of vegetables (especially of the leafy green variety) and fruit, protein, fibre, healthy fats from oily fish and olive oil, plus plenty of nuts and seeds. Limit processed foods, added sugar and alcohol (which Wilson says is a “neurotoxin” that kills and damages brain cells).
A brain-healthy diet doesn’t have to be complicated. Wilson’s go-to is porridge for breakfast: “I use a few different grains in it and top it with raisins and cranberries or chopped apple.” Oats are rich in fibre and nutrient-dense. As recent research suggests, you should be aiming for 30 plants per week – fruit, nuts and seeds all count towards that target.
Eggs are another good breakfast choice: as well as being protein-rich, egg yolks are a good source of choline, the nutrient the body uses to produce neurotransmitters that help regulate memory and mood.
Lunch could be a sandwich made with organic bread (unprocessed), or soup and a roll. Wholegrain varieties are better than white bread or refined products (like bagels), as they’re more nutrient-dense. 
If you’re on the go, Wilson suggests opting for something that is as close to what you could make at home.
For supper, try to incorporate more vegetables and a portion of oily fish: Wilson recommends aiming for two to three portions per week. One of her favourites is pasta with a homemade sauce, a tin of sardines (an excellent source of protein and polyunsaturated fats) and a green salad. Your weekly intake of meat products and red meat shouldn’t exceed 500g, she says.