Most people think of brain health in terms of memory.

But long before memory problems appear, subtle physical changes are already taking place inside the brain — including gradual shrinkage of key areas involved in thinking, learning and decision-making.

A new study published in the Journal of Neurology Neurosurgery & Psychiatry suggests that what you eat may influence how quickly these changes happen.

What makes this interesting is not just that these changes happen — but that the rate at which they happen may not be the same for everyone.

“People who adhered more closely to the MIND diet seemed to show slower structural brain ageing over about 12 years of follow-up,” said senior author Changzheng Yuan, a research professor at Zhejiang University.

What the study found

Researchers analysed data from 1,647 adults with available dietary and MRI data from the Framingham Heart Study.

Participants were followed for an average of around 12 years, with repeated MRI scans used to track changes in brain structure.

As expected with ageing, all participants showed gradual changes, including:

• Reductions in total brain volume

• Loss of grey matter (important for memory and processing)

• Enlargement of fluid-filled spaces in the brain (a marker of atrophy)

However, those who followed the MIND diet more closely showed slower rates of change.

Each 3-point increase in adherence to the diet was associated with:

• A slower rate of grey matter loss — around 20% slower in this study

• Changes equivalent to approximately 2.5 years’ slower brain ageing, based on the study’s modelling of MRI data over time

• Reduced expansion of ventricles, which reflects lower levels of tissue loss

Put simply, people eating more in line with this pattern appeared to maintain brain structure for longer.

What is the MIND diet?

The MIND diet combines elements of the Mediterranean diet and the DASH (blood pressure-lowering) diet.

It focuses on foods thought to support both brain and vascular health.

Foods encouraged:

• Green leafy vegetables (such as spinach and kale)

• Other vegetables

• Berries

• Nuts

• Beans and pulses

• Whole grains

• Fish

• Poultry

• Olive oil

Foods to limit:

• Fried and fast foods

• Pastries and sweets

• Red meat

• Butter and margarine

• Cheese (in excess)

Many of these recommendations align broadly with UK guidance from the NHS, which encourages a balanced diet rich in vegetables, fibre, and healthy fats.

What stood out was not just what people ate — but how these patterns appeared to influence changes within the brain over time.

The standout findings

Some individual foods appeared to play a particularly strong role in the results.

• Berries were linked to slower increases in ventricular volume

• Poultry was associated with both slower tissue loss and better preservation of grey matter

• Sweets and fried foods were linked to faster structural changes associated with brain ageing

The researchers suggest that antioxidant-rich foods may help reduce oxidative stress, while highly processed foods may contribute to inflammation and vascular damage.

A note on unexpected results

Not all findings aligned with existing evidence

Higher intake of whole grains was associated with less favourable brain changes in this analysis, while higher cheese intake showed some protective associations.

These results differ from a wider body of evidence — particularly for whole grains, which are generally associated with improved heart and metabolic health.

As this is a single observational study, these findings should be interpreted with caution. Overall dietary pattern is likely to be more important than any one individual food.

Diet works best alongside lifestyle

The associations observed were stronger in:

• Older adults

• Those who were physically active

• People without obesity

This reinforces a consistent message seen across many studies — that diet works best as part of a broader lifestyle approach, alongside regular physical activity, weight management, and overall cardiovascular health.

What this means in practice

This isn’t about following a strict or complicated diet.

Small, consistent changes are likely to matter most over time.

For example:

• Adding berries a few times per week

• Using olive oil instead of butter

• Including more vegetables and beans in meals

• Reducing ultra-processed foods and sugary snacks

These changes also align with wider NHS advice on supporting heart health — which is closely linked to brain health.

Important limitations

As with all studies of this kind, there are some important caveats:

• This was an observational study, so it cannot prove cause and effect

• Dietary intake was based on questionnaires, which rely on memory

• Participants were predominantly White, which may limit wider applicability

• Other factors, including genetics and changes in diet over time, may have influenced the results

Even so, the findings add to a growing body of evidence suggesting that diet plays a meaningful role in how the brain ages.

The bottom line

Age-related changes in the brain are a normal part of ageing.

But how quickly they happen may not be entirely fixed.

This study suggests that a dietary pattern rich in vegetables, berries, healthy fats and whole foods — and lower in highly processed foods — may help slow some of the structural changes linked to brain ageing.

It’s not a guarantee, and it’s not a replacement for medical care.

But it offers a useful reminder that everyday choices — including what we eat — can have long-term effects on how we feel and function as we get older.