Every day we make choices about what we eat: how to prepare it and how much of it to consume to feel full. But how often do we stop to think about the effect our food is having on our brain power? Answer: hardly ever.
Even most professionals have no idea how closely our diet and our brains are related. Indeed, 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.
Hardly anyone, especially those in positions of power and influence, is paying attention to what I believe is a clear — and vastly under-acknowledged — link between what we eat and who we are, from the cradle (and even earlier) to the grave.
Yet the consequences of ignoring this vital link are, as I will reveal, serious for our children and grandchildren and for the ageing population, too.
According to the respected intelligence researcher James Flynn, IQ levels in many developed countries have, since the 1990s, been dropping at a steady rate after many decades of growth. In fact, his 2018 report states that high IQ scores in the UK have been ‘decimated’.
Hardly anyone, especially those in positions of power and influence, is paying attention to what I believe is a clear — and vastly under-acknowledged — link between what we eat and who we are
If it were simply that IQ had hit a peak, we would perhaps expect scores to plateau. But ‘decline’ and ‘decimation’ indicate that something much more active and worrying has been happening over the past 30 years. So what’s going on?
What do we mean when we talk about ultra-processed foods? Many people have tried to offer simple guidelines as to how to spot and avoid them. For example:
- Don’t eat anything your grandmother wouldn’t have recognised as food.
- Don’t buy anything with more than five ingredients.
- Don’t eat it if sugar is one of the top three ingredients.
- If you can’t pronounce it, don’t eat it.
More scientifically, a nutrition research group has divided food into four categories known as the NOVA classification. It’s worth looking at these in detail.
Group one consists entirely of unprocessed, or natural, foods: edible parts of plants (seeds, fruits, leaves, stems, roots) or of animals and fish (including eggs and milk), and also fungi, algae and water.
Group two, meanwhile, contains products obtained directly from foods in group one.
Group one consists entirely of unprocessed, or natural, foods: edible parts of plants (seeds, fruits, leaves, stems, roots) or of animals and fish (including eggs and milk), and also fungi, algae and water
Examples include sugar and molasses from cane or beet; honey extracted from combs and syrup from maple trees; vegetable oils crushed from olives or seeds; butter and lard obtained from milk and pork; and starches extracted from corn and other plants.
The next group moves into the area of processing and covers products made by adding sugar, oil, salt or other group two substances to group one foods. Examples include canned or bottled vegetables, fruits and legumes; salted or sugared nuts and seeds; salted, cured or smoked meats; canned fish; fruits in syrup; cheeses and unpackaged freshly made breads.
Now to the main area of concern, NOVA’s group four: ultra-processed food and drink products, or UPFDs.
The researchers describe these foods as ‘energy-dense, high in unhealthy types of fat, refined starches, free sugars and salt, and poor sources of protein, dietary fibre and micronutrients.
‘Ultra-processed products are made to be hyper-palatable and attractive, with long shelf life, and able to be consumed anywhere, any time. Their formulation, presentation and marketing often promote overconsumption.’ They add that ‘the ever-increasing production and consumption of these products is a world crisis’.
Ultra-processed food and drink products are industrial formulations typically with five or more, and usually many, ingredients. A key feature is that factory processes with no domestic equivalent are used to create them.
The next group moves into the area of processing and covers products made by adding sugar, oil, salt or other group two substances to group one foods. Examples include canned or bottled vegetables, fruits and legumes
Worryingly, Britain leads the way in the consumption of UPFDs across Europe. In the UK 55 per cent of adults’ calories are from ultra-processed foods, mostly from cakes and biscuits, confectionery, processed meats and soft drinks — and that figure is growing.
Americans are slightly ahead of us, with ultra-processed food and drinks making up 57 per cent of their daily calories. At last count, Italians consumed the fewest UPFDs, with these items making up just 14 per cent of their daily calories.
Though risk is not wholly attributable to diet, it is interesting to note that dementia is only the eighth leading cause of death in Italy — despite the Italians having a longer life expectancy than the British.
In the UK, meanwhile, dementia has overtaken Covid as the country’s leading cause of death, with figures increasing significantly in the past ten years.
Though one glass of processed orange squash isn’t going to kill you, there are grounds to be very concerned indeed about the fact that the majority of our diet now consists of these industrialised foods.
The nature of processing means that brain-healthy nutrients — vitamins, minerals, essential fats and fibre — are lost. In order to extend shelf life and palatability, additional sugar and fats are added.
But most importantly, the convenience of these foods means that they increasingly displace more nutritious, but more labour-intensive, home-made foods from our diets.
Though one glass of processed orange squash isn’t going to kill you, there are grounds to be very concerned indeed about the fact that the majority of our diet now consists of these industrialised foods
For example, during the same period that U.S. consumption of UPFDs increased from 53.5 per cent to 57 per cent of daily energy intake, consumption of minimally processed foods dropped from 32.7 per cent to 27.4 per cent.
A 2015 Brazilian study that assessed the diets of over 32,898 individuals over the age of ten showed that the consumption of UPFDs was inversely correlated to the intake of the essential vitamins B12, D, E, niacin (B3), pyridoxine (B6), copper, iron, phosphorus, magnesium, selenium and zinc.
This is particularly bad news for our hard-working brains, which require a constant supply of nutrients to function properly.
In a 2015 longitudinal study conducted by psychiatric epidemiologist Felice Jacka that looked at the brains of older people over the course of four years, there was a direct relationship between diet quality and the size of the hippocampus — the area of the brain central to learning, memory and emotional regulation. The healthier the diet, the larger the hippocampus.
A separate study by Richard Stevenson of Macquarie University, published in 2020 on The Royal Society’s Open Science website, showed that negative effects on the brain emerge within days on a Western-style UPFD diet.
In this study, 110 healthy people, who typically ate a nutritious diet, were asked to eat a Western-type diet for just a week.
Within that week they were asked to eat, for example, two waffles for breakfast on four of the days and consume a takeaway meal twice. Compared with a control group, the Western-style diet group suffered impairments in hippocampal-dependent learning and memory, and poorer appetite control. The declines in learning and memory correlated to the degree of impaired appetite control, indicating that damage to that crucial part of the brain underlined these changes.
So it is a vicious cycle: the more these foods are consumed, the more damage to the hippocampus, the worse the appetite control, the more these foods are consumed.
I don’t know about you, but I find that terrifying. The fact that measurable brain damage can be induced by just a few days on a diet that many people eat habitually should be a cause for considerable concern.
In the week-long study, participants were asked to eat, for example, two waffles for breakfast on four of the days and consume a takeaway meal twice (Stock image)
And the picture for the rapidly developing brains of our children is, frankly, alarming in the extreme. A 2021 19-year study of the diets of more than 9,000 UK children and young people aged seven to 24 conducted by Imperial College London found that one in five were consuming a whopping 78 per cent of their daily calories from UPFDs.
The main food in the high consumption group were fruit-based or fizzy drinks, ready meals and ready-made cakes and biscuits.
Another analysis of 1,234 mother-child pairs, published in the American Journal of Preventive Medicine in 2018 makes some claims which are truly astonishing. Researchers found an inverse correlation between sugar-sweetened beverages [SSB] consumption by the mother while pregnant and child IQ as measured at ages three and seven.
For every additional daily serving of SSBs, they said, child IQ was between 1.2 and 1.7 points lower by mid-childhood. Consumption of SSBs by children in their early years was linked to 2.4 fewer IQ points per single daily serving.
The bad news continues into adolescence. Just three weeks of low to moderate consumption of SSBs increased blood levels of the pro-inflammatory cytokine C-reactive protein by 60–109 per cent in healthy young men, according to a 2011 study in the U.S.
We should be concerned about this effect on immune signalling because chronic inflammation is associated with a range of physical and mental health conditions such as heart disease, arthritis, depression and anxiety.
Researchers found an inverse correlation between sugar-sweetened beverages [SSB] consumption by the mother while pregnant and child IQ as measured at ages three and seven
It is a disaster, and it is happening right now.
Professor Christopher Millett, NIHR Professor of Public Health at Imperial College London, said: ‘Through a lack of regulation, and enabling the low cost and ready availability of these foods, we are damaging our children’s long-term health.
‘We urgently need effective policy change to redress the balance, to protect the health of children and reduce the proportion of these foods in their diet.’
But for many British children, the trouble has begun before they are even born.
THE state of a woman’s health at the point of conception has a huge impact on the wellbeing of her child.
Because of this, expectant mothers in Britain are warned against drinking alcohol, and it is also common knowledge that an excess of vitamin A in pregnancy can cause malformations in the developing baby.
But most women have no idea about a host of nutrients that are vital to the brain development of children. Tragically for the next generation, the message is simply not being hammered home.
Iodine is one of the most important nutrients for brain development — and yet it is rarely talked about. Rich sources include fish and seafood, dairy and eggs.
So important is its role that the World Health Organization (WHO) has described iodine deficiency as ‘the single most important preventable cause of brain damage’ worldwide.
A total of 67 per cent of the women were deficient in the nutrient, and none of them reported taking supplements or consuming it during pregnancy
The Avon Longitudinal Study of Parents and Children (ALSPAC) is an invaluable cohort study following the health of thousands of children born in 1991 and 1992 in the Bristol area.
One research team analysed the cognitive outcomes of the children of 958 women after studying the mother’s iodine status during the first trimester of pregnancy.
The findings were truly shocking. A total of 67 per cent of the women were deficient in the nutrient, and none of them reported taking supplements or consuming it during pregnancy.
The researchers conclude: ‘Low maternal iodine status was associated with an increased risk of suboptimum scores for verbal IQ at age eight years, and reading accuracy, comprehension, and reading score at age nine years, even after adjustment for many potential confounders.
‘Furthermore, our results suggest a worsening trend in cognitive outcome with decreasing maternal iodine status.’
For Britain’s children, this is catastrophic. The negative effects of iodine insufficiency during gestation, when the brain is being built, are irreversible. Insufficient iodine in the first 14 weeks of pregnancy permanently suppresses a child’s IQ.
Although it accounts for just 2 per cent of our body weight, the brain is responsible for around 23 per cent of the number of calories we burn when at rest.
For a baby, whose brain comprises a larger proportion of its body mass, that figure rises to a huge 74 per cent.
Although it accounts for just 2 per cent of our body weight, the brain is responsible for around 23 per cent of the number of calories we burn when at rest
The larger the brain, the bigger the need for nutrients. And perhaps the most important of all of these is the Omega-3 group of fats, specifically docosahexaenoic acid, or DHA, found in fatty fish such as salmon, shellfish and fish oils.
DHA is the cornerstone of brain development, with its concentration highest in the prefrontal cortex, the region of the brain that coordinates our higher functions. Which is why I find it so worrying that just a tiny percentage of UK children are getting enough of it.
According to a survey by nutrition researcher Sibylle Kranz and colleagues published in 2017, only 4.5 per cent of children in Britain were meeting the oily fish consumption recommendations.
Available evidence suggests this shortfall is not being rectified through supplements. On top of that, other components of the typical British diet actually inhibit the uptake of Omega-3. What sort of impact must this be having on the brain development, cognition and mental health of our young people?
A recommendation that UK adults should ‘eat at least two portions of fish, of which one should be oily, weekly’, was first made in 1994. Ten years later the Scientific Advisory Committee on Nutrition bemoaned the disastrous lack of take-up.
‘The majority of the UK population does not consume enough fish, particularly oily fish,’ said its report. The guidance, it added, was a minimum, ‘and does not correspond to the level of fish consumption required for maximum nutritional benefit’.
Since then there has been a rapid increase in the number of people reducing or eliminating animal foods from their diets.
We simply do not know how many women are consuming sufficient DHA for the optimal brain development of a baby. My best educated guess is hardly any.
In a 2007 analysis of the ALSPAC data, researchers looked at the relationship between maternal fish consumption at 32 weeks’ gestation and child IQ.
They found that the more fish a mother ate during pregnancy, the higher her child’s IQ.
Moreover, they found no evidence of a harmful effect of high fish consumption on child health in relation to concerns about mercury. In fact, a separate follow-up study published last year found that higher maternal and umbilical cord blood levels of mercury were associated with better cognitive outcomes (higher IQ and mathematical reasoning) and no negative effects.
It’s not that mercury is good for the brain, but that fish consumption is so beneficial that it cancels out potential harm from the mercury. This means that the oft-repeated advice to avoid eating fish during pregnancy due to fears about mercury may have inadvertently been doing more harm than good when it comes to our children’s brains.
If DHA is one of the building blocks of brain cells, then a little-known, unsung nutritional hero known as choline (found in liver, eggs, meat, cheese and nuts) is the mortar — and just as necessary for constructing strong neurological foundations.
In an illuminating 2022 study from the U.S. conducted by neurobiologist Charlotte Bahnfleth and colleagues, women were divided into two groups during the third trimester of their pregnancy.
This means that the oft-repeated advice to avoid eating fish during pregnancy due to fears about mercury may have inadvertently been doing more harm than good when it comes to our children’s brains
One group received a supplement of the recommended adequate intake of choline.
The second group received nearly double that amount.
Seven years later the researchers revisited the families and gave the children a series of cognitive tests. They found that the children of the mothers who received the higher dose were better able to sustain attention and were more accurate in their responses.
Simply put, children who can pay attention do better in school. Attention span is a key predictor of school grades in literacy, vocabulary and maths above the contribution of IQ.
These startling findings indicate that the current recommendations might be well wide of the mark when it comes to the needs of pregnant women. Of additional concern is that an analysis of dietary intake indicates that typical choline consumption in British adults is significantly below the recommended levels.
OUR brains are in trouble. Rates of mental illness and neurodegenerative disease in Britain are on the rise and IQ is in decline.
There are critical periods of neurodevelopment, during which it is essential to provide key and irreplaceable nutrients. Many of these are in the earliest stages of life.
After these windows close, improved nutrition and/or supplementation may be beneficial but they are very unlikely to recoup all of the losses.
My intention is not to point fingers or blame parents for not eating ‘correctly’ during pregnancy or not feeding their children ‘the right things’.
Not at all. Rather, my argument is that we all have inadequate, insufficient and out-of-date information on the impact of nutrition on brain health, and unequal access to nutritious foods.
The Government has an obligation to make important health information available and accessible so that people may then act on it.
It has a responsibility to enact health policy to support the physical and mental health of the population. In these duties of care, it is my case that the Government is failing.
But it’s not too late. What we urgently need is an overhaul in our understanding of mental health with a focus on prevention, risk reduction, early intervention and resilience.
Though we can’t control external factors like pandemics or earthquakes, we CAN, the evidence suggests, reinforce and fortify our brain architecture.
With enough people power, we can start turning the tide right now. We must.
n Kimberley Wilson is a chartered psychologist with a Masters degree in nutrition.
n Adapted from Unprocessed: How The Food We Eat Is Fuelling Our Mental Health Crisis by Kimberley Wilson, to be published by W. H. Allen on February 23 at £22. © Kimberley Wilson 2023. To order a copy for £19.80 (offer valid to 25/02/23; UK P&P free on orders over £20), visit www.mailshop.co.uk/books or call 020 3176 2937.