Top psychologist and nutritionist Kimberley Wilson explains how your diet can help reduce cognitive decline
Up to four in 10 dementia cases could be prevented with simple lifestyle changes, recent research suggests.
With 1million Brits and almost 7million Americans now suffering from devastating neurological illness, and more predicted to be diagnosed in the future, preventative solutions are needed.
Diet, experts say, is a key area to focus on. A raft of studies have repeatedly shown the foods we eat can influence brain health, mood and also cut the risk of cognitive decline.
Most recently, experts discovered that the earlier in life you start eating well the more likely you are to stay mentally sharp in your 70s and beyond.
So what should be on the menu? To find out we spoke to top psychologist and nutritionist Kimberley Wilson, who has devoted her career to studying how diet influences the mind.
Oily fish and greens to slow cognitive decline
People who eat lots of leafy greens, such as spinach and kale, and oily fish have been shown to have lower rates of cognitive decline.
The reason? Both foods are sources of omega-3 fats.
According to Alzheimer’s Society omega-3 is thought to reduce inflammation in the brain — something that may contribute towards the development of dementia.
‘Older people who eat leafy greens on a daily basis have brains that are 11 years younger than their peers,’ Ms Wilson, who will be speaking at New Scientist Live 2024 at the ExCeL London on October 12, told MailOnline.
She added: ‘Your brain has a really high metabolic rate and when a tissue is really active it produces a lot of free radicals and oxidants which can damage the brains tissue.’
‘But these compounds in leafy greens seem to help dampen down that oxidative stress,’ she explained.
According to Alzheimer’s Society omega-3, a fat found in oily fish, is thought to reduce inflammation in the brain — something that may contribute towards the development of dementia
People who eat lots of leafy greens, such as spinach and kale have been shown to have lower rates of cognitive decline
Berries for a brain boost
From strawberries to aubergines we should all be ‘eating the rainbow’ to feed our brains.
That’s because these colourful foods can help you get your daily dose of polyphenols — a group of naturally occurring compounds found in plants that have antioxidant properties.
Found in high levels in foods like berries these substances can boost blood flow in the brain.
Boosting blood flow in the brain can help ward off vascular dementia, a form of the condition linked to poor circulation that eventually kills brain cells, the NHS says.
Ms Wilson explains we have a whopping 400 miles of blood vessels in our brains.
That means we need a really strong blood supply and plenty of nutrients to keep everything working.
Ms Wilson said: ‘You need a really good blood supply to provide the brain with all of the glucose and the nutrients and the oxygen it needs to keep your brain cells working well.
‘And what polyphenols do is, when they broken down in the body, they produce a compound of gas called nitric oxide, which basically widens your blood vessels and makes them more flexible so more blood can get in,’ she added.
If you are able to get more blood and therefore more nutrients and oxygen into the brain, then you will get better brain function in the short term, Ms Wilson said.
But if you continually add these nutrient rich foods into your daily diet then, your brain will also stay healthy in the long-term, she adds.
Eating vegetables could make you happier
Eating a healthy meals won’t necessarily boost your mood immediately, but years of eating well can ward off depression.
Ms Wilson explains that if she were to take a group of people and look at their levels of depression and compare that to their diet over a period of 15 years, those with a healthier diet are shown to have a 30 per cent reduced risk of depression compared to those with the least healthy diet.
‘So, maintaining a healthy diet seems to reduce your risk of later developing mood disorders over the longer term,’ she added.
Depression is associated with roughly double the risk of developing dementia, according to a review that combined results from 27 research studies, Alzheimer’s Society explains.
Therefore eating food that keeps your mood up, could also have some long-term benefits.
However, when it comes to eating junk food and ultra-processed foods it’s not clear if it is the presence of them or the absence of healthier food that is to blame for the mood change, Ms Wilson explains.
Alzheimer’s disease is the most common cause of dementia. The disease can cause anxiety, confusion and short-term memory loss
Eating food that keeps your mood up, could also have some long-term benefits on your cognitive health
Fibre isn’t just for the gut
Fibre found in fruit and vegetables is fantastic for our gut health, but a healthy gut could also mean a healthy mind.
That’s because a byproduct of fibre fermentation in the gut, helps protect our brains.
‘When fibre is broken down by the gut microbes they produce the byproduct, short chain fatty acids and one of those is called butyrate and it helps protect the blood brain barrier,’ Ms Wilson said.
These short chain fatty acids have numerous jobs, they reduce inflammation in the gut and they also feed the cells of the gut lining and the blood brain barrier — a tightly locked layer of cells that defend your brain from harmful substances.
That’s important because when the blood brain barrier breaks down that can trigger inflammation in the brain, which in the long-term is thought to cause cognitive decline.
‘So, even though it is indirect, as fibre isn’t helping your mood, it is supporting by helping that protective barrier,’ Ms Wilson said.
Overloading on sugar could increase your risk
Consuming too much sugar, fatty foods and carbohydrates is a recipe for gaining weight.
While eating sugar won’t directly increase your risk of developing dementia by triggering inflammation, putting on weight as a result can.
‘At the moment, it’s not very clear that sugar per se is pro-inflammatory, particularly where the individual is in a state of energy balance,’ Ms Wilson explained.
‘It seems to be more that a dietary pattern where you consume more energy than you burn is linked to increased inflammation, and consuming high amounts of sugar makes it easy to take on more energy than you expend,’ she added.
If you eat too much sugar you will, as a result, be consuming more energy than you need, which can cause excess fat to accumulate around the waist.
This, Ms Wilson warns, is a risk factor for developing type 2 diabetes, and diabetes increases someone’s odds of developing dementia.
However, there is also a direct link to inflammation — which has been linked to cognitive decline — when it comes specifically to sugary drinks.
‘The exception seems to be sugar-sweetened beverages (soft drinks), where consumption is linked to increased markers of inflammation in healthy young men and children,’ she said.
But she adds that a diet high in refined sugar may also lack fibre — which is known to have an anti-inflammatory effect.
EATING SEAWEED BOOSTS IQ
Seaweed may not be a go-to green for most, but eating it could make you — and your future children — smarter.
That’s because a key nutrient in seaweed is iodine, one of the best known nutrients for boosting IQ.
In fact, the World Health Organization calls iodine the leading cause of preventable brain damage worldwide.
Top psychologist Kimberley Wilson explains the thyroid gland, which keeps your metabolism running, uses iodine, which is vital during pregnancy.
‘During pregnancy it kick starts the development of the brain, and you need enough iodine for the mother to have her own thyroid hormone and then, because the baby’s thyroid gland doesn’t start working by itself until right the second trimester, she needs also enough iodine to make enough hormone for the baby,’ Ms Wilson said.
A key nutrient in seaweed is iodine, one of the best known nutrients for boosting IQ
However, in areas of the world where iodine is low, there is up to 15 per cent lower IQ in that population versus areas that have higher iodine, she adds.
Although usually this deficiency is seen in landlocked areas because the richest source of iodine is seaweed, the UK is affected.
‘It’s seen that the kind of flyover states, or the central states of places like India and parts of Asia and in the in Europe, in the Alps, but actually in the UK, 67 per cent of pregnant women are iodine deficient.
‘You see these associations even in the British population, where you can track maternal iodine, the amount of iodine in the mother’s urine tracks with her child’s IQ.’
However, you don’t necessarily need to buy seaweed from your local Japanese food shop, instead some types of salt and milk can contain iodine.
Salt has been iodized in America since the 1920s following problems the nation faced with goiter — a swelling in the neck that occurs when the thyroid gland enlarges.
Goiter can be triggered by the body not having enough iodine and so iodizing salt helped hugely and not just to solve goiter, it also improved IQ, Ms Wilson explains.
‘They saw a 10 year growth effect in what’s called the Flynn effect, which is the growth in IQ, across a span of one or two years simply by iodizing salt,’ she added.
In the UK the next best source to seaweed is dairy milk, which is why those that eat a plant-based diet and are not properly supplementing can be deficient.
But if you want to see the long-term benefits of iodine, you shouldn’t delay as it could impact your health up to a decade down the line, Ms Wilson warns.
‘Obviously if you go vegan at 22 nobody is really thinking about their iodine status and certainly not questioning if their iodine status will have an effect on their babies brain that they might have in ten years time,’ she said.
