Diet Not Genes Is Driving Dementia According To The British Medical Journal


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

The study also 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.

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 online 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 their 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 test at 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.

The BMJ study is here:

The free Cognitive Function test and Dementia Risk Index assessment is accessed here:

The evidence that only 1% of Alzheimer’s is caused by genes is here:

For more information on the citizen science campaign see ‘Alzheimer’s is Preventable – A Manifesto for Change’ at:


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