Diet and dementia risk explained

Dementia risk

Growing evidence suggests that a healthy, balanced diet may support good brain health and reduce our risk of dementia.

What does the research say?

What should I eat to keep my brain healthy?

There is no single diet that can prevent dementia. However, some ways of eating have been linked to better brain health.

For example, a Mediterranean‑style diet has been linked to a range of health benefits, including brain health. More research is still needed to understand how it may affect dementia risk directly.

This way of eating is generally lower in:

meat
dairy

And higher in:

fresh fruit and vegetables
cereals
beans
nuts
‘healthy’ fats like olive oil.

You do not need to follow one specific diet. These are general patterns that can be adapted to fit different cultures, preferences and budgets.

The Eatwell Guide shows what a balanced diet can look like and how much of each food group to include. Versions and adaptations are available to reflect different cultural diets.

Do specific foods or nutrients make a difference?

Does diet matter as we get older?

What foods should I avoid to reduce dementia risk?

Research suggests that diets high in ultra-processed foods may be linked to a higher risk of dementia.

Regularly eating too much sugar and saturated fat can increase the risk of heart disease, diabetes and dementia.

High fat and sugary snacks like sweets, biscuits and fizzy drinks should be an occasional treat and only consumed in small amounts.

Some foods including processed meats, butter, cheese and cakes, are high in saturated fat. Eating these often can raise cholesterol and increase the risk of other health problems.

It is never too late to make changes to our diet, even just a small change can have a major effect on both brain health, and general health and wellbeing too.

It’s also important to limit the amount of alcohol we drink.

About the evidence

Most of what we know about dementia risk comes from observational studies, which follow groups of people over time to look for patterns in health and lifestyle.

For example, studies like Insight 46 have followed people for decades to understand how health across life is linked to brain health and later on.

This is often the most practical way to study dementia risk. Many risk factors cannot be tested in trials in a fair or ethical way. Dementia also develops over many years, so studies can take a long time to show results.

Observational studies can show when something like our diet or occupation are linked to a higher or lower chance of dementia. But they cannot prove that something directly causes dementia, or that changing it will definitely reduce risk. These studies look at patterns across large groups, not what will happen to any one person.

Randomised controlled trials give stronger evidence because participants are assigned to different groups at random. This design makes it more likely that differences in outcomes, for example our risk of dementia, are caused by the intervention, for example a diet change, rather than by other factors.

But these studies are harder to do in dementia research. They often take many years and may test several changes at once, making results harder to interpret.

Newer trials are helping to build a clearer picture of what may support brain health. No single study can give a definite answer, but it is all research findings together that help us understand what is important for our brain health and risk of dementia.

Frequently asked questions about diet and dementia risk

Are there any foods that cause dementia?

No single food or eating pattern has been shown to cause dementia.

However diets high in saturated fat, salt, and added sugar are linked to poorer heart and blood vessel health. Because heart health and brain health are closely connected, these eating patterns may increase dementia risk over time.

On the other hand, eating a balanced diet with plenty of vegetables, fruit, wholegrains, and healthy fats is linked to better overall brain health. Most cases of dementia develop because a mixture of factors together, and diet is just one part of the picture.

Can certain fats reduce our risk of dementia?

Saturated fats found in processed meat, dairy and fried foods are linked to poor cardiovascular health. Having poor cardiovascular health increases your risk of developing dementia, and a range of other health conditions.

Fats found in oily fish, nuts, olive oil and avocados are called poly and monounsaturated fats. These can be enjoyed as part of a healthy balanced diet in moderate amounts, and they have been found to be beneficial to our heart health.

However, there is no evidence to suggest that consuming high levels of these fats protects you against the development of dementia.

Do ultra-processed foods (UPFs) affect dementia risk?

Ultra-processed foods (UPFs) are foods made mostly in factories. They contain little or no whole ingredients. They often include added sugar, salt, fat and artificial ingredients.

Examples include:

sugary drinks
crisps
cakes and biscuits
sweets and chocolate
ready-to-eat meals.

Research on UPFs and dementia risk is still emerging. Several studies suggest that people who eat a lot of UPFs may have a higher risk of dementia.

For example, one large review found that people with the highest UPF intake were more likely to develop dementia than those with the lowest intake. However, not all studies show the same results.

It is also important to know that these studies only show a link. They cannot prove that UPFs cause dementia directly.

Other factors may play a role, such as:

overall diet
physical health.

More research is needed to understand this link. Future studies need to measure UPF intake in a consistent way across large groups of people.

Can eating eggs affect dementia risk?

There is no evidence that eating eggs increases dementia risk. There is also no evidence that you need to eat eggs to protect brain health.

Some studies have looked at egg consumption and dementia, but no single food has been shown to meaningfully affect dementia risk on its own. What matters much more is a person’s overall diet and lifestyle.

Well‑planned diets with or without eggs can support good brain health.

Can Ginkgo biloba, green tea, or turmeric help people with dementia?

There is currently no conclusive evidence that ginkgo biloba, green tea or turmeric can prevent, or treat, dementia.

These natural products have mild anti-inflammatory properties, leading some to claim that they might protect the brain from inflammation linked to dementia. Research results so far have been mixed.

The products are being studied in early-stage trials to see if they can help and to understand whether they offer protection from dementia.

Always speak to your doctor before starting supplements as they can cause side effects and interfere with prescription medications you might be taking.

Can coffee affect dementia risk?

Some studies have found that people who drink coffee are slightly less likely to develop dementia. These studies show a link, but they don’t prove that it is the coffee itself that reduces dementia risk.

Coffee contains caffeine and other natural compounds that may support brain and heart health. However the lower risk identified in studies could also be due to other lifestyle factors, such as overall diet, physical activity, or social habits in coffee drinkers.

Drinking coffee in moderation is generally safe for most people, but it is not a proven way to prevent dementia. Drinking too much can cause side effects like sleep problems, anxiety, or a fast heart rate in some people.

Can fasting reduce dementia risk?

There is not enough evidence to show that fasting reduces the risk of dementia.

Some studies in animals suggest that periods of fasting might affect brain health, but research in people is still limited. So far studies in humans have not shown clearly that fasting protects against dementia.

Fasting is also not suitable for everyone, and for some people it could do more harm than good. For dementia risk reduction, the safest advice is still to eat regular, balanced meals that support heart and overall health.

Frequently asked questions about supplements and dementia risk

Can B vitamins protect against dementia?

There is currently not enough evidence to suggest that B vitamin supplements will prevent or slow the onset or progression of dementia.

High blood levels of a chemical called homocysteine have been linked to an increased risk of Alzheimer’s disease. Homocysteine is produced by the body and found in certain foods. Certain B vitamin deficiencies, such as vitamin B12 and folic acid, can cause high homocysteine levels if left untreated.

While the symptoms caused by B vitamin deficiencies are similar to dementia symptoms, they are different conditions. B vitamin deficiency can be common, if you are concerned you have one you can ask your doctor for a blood test.

The latest evidence suggests that while supplements of folic acid and vitamin B12 can reduce homocysteine levels in deficient individuals, they do not affect memory and thinking skills in people who do not have a vitamin B12 deficiency.

Should I take aspirin to prevent dementia?

This is not recommended. Medicines known as non-steroidal anti-inflammatory drugs (NSAIDs), which include aspirin and ibuprofen, have been tested to find out whether they could reduce Alzheimer’s risk.

Clinical trials have found no evidence that low-dose NSAIDs can prevent dementia. There are also concerns about side-effects which can sometimes be serious, so it is not advised to take these drugs to protect against dementia.

Can vitamin D supplements reduce dementia risk?

Some studies have found that low levels of vitamin D are linked to a higher risk of developing dementia. However, this does not mean that taking vitamin D supplements has been proven to reduce dementia risk.

Most studies cannot show whether low vitamin D levels cause dementia, or whether they are linked to other factors such as overall health, mobility, or time spent outdoors. So far, studies of vitamin D supplements have not shown clear benefits for preventing dementia.

In the UK, the NHS recommends that adults consider taking a daily vitamin D supplement during the autumn and winter months to support bone and muscle health. This advice is not specific to dementia prevention.

What can I do today?

Healthy eating doesn't have to mean changing everything at once. You could:

add an extra portion of fruit or vegetables to a meal.
swap a sugary drink for water.
use the Eatwell Guide to find one change you could try.

Eating more healthily doesn’t mean giving up your favourite meals. Small swaps can make a difference. Learn more from Dementia Community Champion™ Usha’s approach to healthy eating.

It is never too late to start thinking about your brain health.

Vegetables laid out on a surface, including tomatoes, mushrooms, green beans, chillies and garlic.

Join the Big Brain Health Check-in

Explore your brain healthy habits and discover how to look after your incredible brain.

Further resources

Healthy eating looks different across cultures. Traditional foods and cooking styles can all be part of a balanced diet, and the Eatwell principles can be adapted to suit many cultural preferences.

We offer bespoke resources for South Asian, and African and Caribbean communities. We also recognise that people from other cultural backgrounds may want tailored information, and we will continue to expand these resources over time.

Person cooking in a kitchen and another person looking at them smiling

Our research

Alzheimer’s Research UK funds studies to understand how lifestyle factors, such as diet, may help keep the brain working well as we age.

Researchers at the University of Cambridge are looking at whether following the Eatwell Guide could support brain health. At University College London, researchers are studying how diet may affect changes in the brain linked to Alzheimer’s disease.

Alzheimer’s Research UK have also funded research by University College London looking at how our diet affects brain changes that are linked to Alzheimer’s disease. You can find out more about this here.

Other research looks at how our health and habits change as we get older, and how this links to dementia risk. This includes long‑term studies that follow people over many years, and large reviews of evidence that bring together what we know about reducing risk.

Find out more about our research

Watch our online public event to hear from our researchers

Research is the only way we'll find new ways to prevent, diagnose and treat dementia and scientists need your help.(opens in new tab)

Without people volunteering to take part in research, finding a cure would be impossible. Find out more.

Find out more about dementia risk

Latest news about diet and brain health

man and woman unpacking shopping together

How might a UK-specific diet reduce dementia risk?

RS744_Alex_Wallace_Photography_ARUK__Rebrand_House_001-976

Three ways to show your heart (and brain) some love during Heart Month

Delicious summer recipes from John West

Sardines_with_caramelised_red_onions_and_basil_2160x960px-1593x708

Why we’re partnering with John West to raise awareness of brain health

SCL_Candice-Brown_The-Best-Potato-Salad_Landscape_050922-3

Candice Brown shares three healthy recipes for your brain health

Lower intake of flavanols linked to age-related memory loss, suggests new study

Mediterranean diet associated with decreased risk of dementia

What should we eat for a healthy brain?

New US study shows possible link between antioxidants in diet and slower cognitive decline

Does diet really affect our dementia risk?

Downloads

Read more about dementia risk, including the factors that we may be able to influence.

Reducing your risk of dementia

PDF, 6.14 MB, 21 pages

If you have more questions about dementia and research, our Infoline can help.

Call us on 0300 111 5 111 or email infoline@alzheimersresearchuk.org.

Information on this page does not replace any advice that doctors, pharmacists or nurses may give you.

This information was updated in July 2026 and is due for review in July 2028. It was written by Alzheimer's Research UK's Information Services team with input from lay and expert reviewers. Please get in touch if you'd like a referenced copy.
This information is produced with support from The Perfume Shop who had no input into the content.