Dementia isn’t an inevitable part of getting older — and a growing body of research suggests that nutrition may play a greater role than once believed.

In June 2025, a large-scale study published in Nutrients analysed dietary data from over 180,000 adults and followed them over a decade.

The aim: to see whether intake of certain vitamins and minerals was associated with future dementia or Alzheimer’s diagnoses.

The researchers found seven key nutrients consistently linked with lower risk — even after adjusting for factors like age, sex, physical activity, and underlying health.

While this kind of research doesn’t prove cause and effect, it adds to a growing picture of how small, consistent changes to your diet may support long-term brain health.

Here’s a closer look at the nutrients highlighted — and where to find them.

1. Magnesium: Steadier Brain Function, Lower Dementia Risk

Magnesium plays a vital role in nerve transmission, memory formation, and blood flow to the brain.

In the 2025 study, participants with the highest magnesium intake were 19% less likely to develop dementia than those with the lowest.

This aligns with previous research from the University of Adelaide, which found lower magnesium levels in people with Alzheimer’s disease.

Magnesium is also known to help regulate inflammation and oxidative stress — two key drivers of cognitive decline.

✅ Found in: Leafy greens, whole grains, legumes, nuts and seeds, dark chocolate.

2. Vitamin E: Natural Protection for Brain Cells

Vitamin E is a powerful antioxidant that helps protect brain cells from oxidative stress — a type of damage that builds up with age.

The Nutrients study found that those with the highest vitamin E intake had a 14% lower risk of developing dementia compared to those with the lowest intake.

Other studies have linked low vitamin E levels with faster cognitive decline, particularly in older adults.

✅ Found in: Sunflower seeds, almonds, spinach, avocado, vegetable oils (such as olive or sunflower oil).

3. Vitamin A: Supporting the Brain's Defence System

Often known for its role in vision, vitamin A also plays a part in immune function and inflammation control — both of which affect the brain.

In the study, higher vitamin A intake was associated with a 13% lower risk of developing dementia.

Vitamin A helps maintain the health of the blood-brain barrier and may prevent the build-up of amyloid plaques — a hallmark of Alzheimer’s disease.

✅ Found in: Carrots, sweet potatoes, butternut squash, liver, and dark leafy greens.

4. Zinc: A Trace Mineral With a Big Impact

Zinc is essential for immune function, brain signalling, and regulating oxidative stress. It also supports the formation and repair of neurons.

The 2025 study found that participants with the highest zinc intakes were 12% less likely to develop dementia than those with the lowest.

Zinc deficiency has been observed more frequently in people with cognitive decline, and studies suggest it may play a role in slowing memory loss.

✅ Found in: Pumpkin seeds, cashews, chickpeas, lentils, meat, and whole grains.

5. B Vitamins & Omega-3s: A Powerful Nutrient Pair

Folate (vitamin B9) and vitamin B6 were both independently associated with reduced dementia risk in the Kang study — with folate linked to a 15% lower risk, and vitamin B6 to a 12% reduction.

These vitamins are essential for clearing homocysteine, a compound that can damage blood vessels and has been linked to cognitive decline.

Importantly, several trials — including work by Oxford University — suggest that B vitamins are most effective when omega-3 levels are also sufficient.

Without enough omega-3s, B vitamins don’t seem to offer the same brain-protective effects.

Omega-3 fatty acids (particularly DHA) are essential for brain structure and function. Though not part of the Kang study, omega-3s have been shown in multiple trials to reduce brain shrinkage and slow memory loss in people with mild cognitive impairment.

✅ Found in: Folate & B6: Leafy greens, beans, fortified cereals, bananas. Omega-3s: Oily fish (like salmon and mackerel), flaxseed, walnuts, chia seeds.

6. Fibre and Brain Health: An Emerging Connection

While fibre didn’t show as strong a link in the Kang study, growing research suggests it still plays a role in cognitive health — largely through the gut-brain axis.

A 2024 randomised controlled trial published in Nature Communications found that 12 weeks of daily prebiotic fibre significantly improved memory and brain function in adults over 60.

The researchers pointed to better gut health and reduced inflammation as likely mechanisms.

Gut microbes help produce compounds that affect brain signalling and immune function, and disruptions in gut health have been linked to age-related cognitive decline.

✅ Found in: Jerusalem artichokes, onions, garlic, bananas, oats, legumes, and prebiotic fibre supplements.

A Final Word

There’s no single superfood that will prevent dementia — and no nutrient works in isolation. But evidence is growing that a diet rich in magnesium, antioxidants, B vitamins, and fibre may support the brain as it ages.

These are changes anyone can start making: more colourful vegetables, regular portions of oily fish, and a broader mix of whole foods.

Because while ageing is inevitable, cognitive decline might not be.