Food and Behaviour Research

Donate Log In

Food Affects Behaviour: 20+ Years of FAB Research – What next? - BOOK HERE

Diet, not genes, is driving dementia says British Medical Journal

Food For The Brain

Mediterranean diet

Switching from an average to a healthy lifestyle, with positive diet changes being key, can dramatically reduce a person’s future risk of developing cognitive decline and dementia


Diet is the single biggest determinant of dementia risk, according to this new 10-year follow-up study of 30,000 older adults.

The next most important influences were staying active, engaging in learning and other cognitively challenging activities, physical exercise, and positive social interactions.

All too often, other studies assessing risk factors for dementia actually 'factor out' nutrition and diet in their statstical analyses, by focusing on 'biomarkers' and/or physical health conditions that are themselves influenced by nutrition and diet - such as blood pressure / heart disease, blood sugar / diabetes, vision or hearing loss etc.

Increasing evidence from basic scientific research, clinical studies and other population studies all supports this same conclusion - that nutrition is a key determinant of risk or developing age-related cognitive impairment and dementia.

Some randomised controlled clinical trials also show significant protective effects of nutrition and diet against both the physical brain shinkage and the clinical and cognitive problems associated with dementia.
However, studies of actual diets cannot be 'double-blinded', so most such trials involve supplementation of individual nutrients or combinations of these - which can never provide everything that real foods do.

What's more, the long timescales over which nutrition can influence dementia risk also make definitive clinical trials in humans impossible - as some key nutritional factors actually date back to early life, and initial brain development.

So what IS a healthy diet for dementia prevention? 

As numerous other studies have shown, a healthy diet includes primarily whole and minimally processed foods - and very importantly, not only vegetables and fruits, nuts & seeds, legumes and whole grains, but also fish and seafood, eggs and small quantities of milk and dairy products (especially fermented ones such as yogurt or kefir) and/or fresh or minimally processed meat.

Mediterranean-type, 'Nordic' or other traditional (pre-industrial) diets, as well as the MIND and DASH diets, so-called 'Paleo' diets and many others all fit this description. 

Importantly, while almost all are 'plant-based' (in terms of proportions of food consumed within each meal, snack or the diet as a whole) they are NOT 'plant-exclusive'. This is because so many absolutely essential brain nutrients are either not found in plant foods, or are not available from these in sufficient quantities for brain health. Strictly vegan (and most vegetarian) diets therefore need to be supplemented to provide adequate intakes of these.

For details of the underlying research, see:

For more information on what key elements of modern diets can most negatively affect brain health and reduce resilience to dementia (and other mental health conditions), please see our recent FAB webinar.  (This can still be accessed - along with handouts of the speakers' slides and other information - either as a standalone event, or for FAB Associates, via our online Associates library). 

Both speakers gave compelling accounts of why improving nutrition really is fundamental to reducing the current 'mental health crisis' - and what individuals, as well as professionals and policymakers, can do in practical terms to improve this for themselves, or for those they work with or serve.
Food For The Brain 

A hugely significant study in the British Medical Journal into age-related cognitive decline and dementia has stated that changing your diet and lifestyle from bad to good cuts your future risk of developing dementia by a massive nine times [1].
The study shows, significantly, that whether or not you inherit the ApoE4 ‘Alzheimer’s gene’ that one in five people carry, it makes no difference to the positive reduction in risk achievable by simple diet and lifestyle changes [2].
Eating a healthy diet was also the most important prevention step, followed by an active lifestyle, with one’s intellectual life, then physical activity, then social interactions being the next most important steps. Eating a healthy diet was about twice as important as exercise in predicting cognitive decline.
This study, published on 25th January 2023, followed over 30,000 people over a decade and found that those with a healthy diet were about seven times less likely to have age-related cognitive decline or dementia than those with an ‘average’ diet and about nine times less likely to develop dementia than those with an unfavourable diet.
The assessment of a healthy diet was based on intake of fish, eggs, fruits, vegetables, legumes, nuts and tea, among other foods known to predict lower risk.

Increasing evidence that Alzheimer’s and Dementia are preventable

“These results provide an optimistic outlook, as they suggest that although genetic risk is not modifiable, a combination of more healthy lifestyle factors are associated with a slower rate of memory decline, regardless of the genetic risk,” wrote the study authors.
This study has been warmly welcomed by charity Food for the Brain, as it backs up their own research and the work they have been actively carrying out for 10  years, to help people reduce their risk of age-related cognitive decline.
Food for the Brain offers a free online assessment of a participant’s diet and lifestyle, called the Dementia Risk Index, which works out a person’s overall risk. The assessment also includes a cognitive function test to assess your memory. This charitable ‘citizen science’ action group have also just launched COGNITION, an interactive, personalised ‘brain upgrade’ programme that then shows you, week-by-week, how to make positive changes to bring your risk closer to zero.
Indeed, the on-line test assesses all the same risk factors the British Medical Journal study has shown impact a person’s future risk – diet, active physical, intellectual, social lifestyle, smoking and drinking habits.  
According to Professor David Smith from the University of Oxford, one of the charity’s scientific advisors, “Genes can only exert effects via non-genetic mechanisms and these mechanisms are often susceptible to modification by, for example, improving one’s diet.

"This study shows that diet and lifestyle are much more important than inheriting a gene variant such as ApoE4. Less than 1% of Alzheimer’s is directly caused by genes. With no clinically effective drugs, and minimal role of genes, this study confirms that the focus must be on making diet and lifestyle changes that reduce risk of developing dementia, as are doing.

"It also shows that switching from an average to a healthy lifestyle, with positive diet changes being key, can dramatically reduce a person’s future risk of developing cognitive decline and dementia.” 
Another member of the science team, Dr Celeste de Jager Loots, Research Associate at Imperial College’s  AGE Unit where she researches risk factors and prevention of Alzheimer’s and dementia, explains that

While having inherited certain genes can be used to predict risk of dementia, that risk is changed by making positive diet and lifestyle changes. The emphasis needs to be on changing diet and lifestyle, especially since one cannot change one’s genes. The earlier one starts with a healthy lifestyle the better the chance of preventing effects of genetic risk.”
Risk for dementia can be detected from the age of 35 and subtle changes, picked up by Food for the Brain’s cognitive function test, can be seen up to 40 years before a diagnosis. The charity wants anyone over 35 to take the test and start making positive diet and lifestyle changes. “The average person can cut their future risk by three quarters just by making simple diet and lifestyle changes.” says Patrick Holford, who is directing the Alzheimer’s prevention project. “This prevention approach, if we reach enough people, could cut cases of dementia in the UK by a third. That’s why we are urging everyone over 35 to tell everyone they know to take the free and scientifically – validated and free Cognitive Function Test. Alzheimer’s dementia, which accounts for the vast majority of dementia, is irreversible. But it is preventable, as this study shows.”
Two thousand people every month are joining this campaign, assessing and reducing their risk. Over 380,000 people have now taken the test.