Diet, dementia and the power of lifestyle choices

Dr Linia Patel explores dementia and the power of lifestyle and diet choices to impact individuals with dementia.

Globally, around 55 million people live with dementia, and this number is expected to double by 2030 due to our ageing population.

Dementia is a devastating diagnosis – for the individual but also for the people who love them. I’ve witnessed it first hand. My darling late mother, who was fiercely independent and razor sharp, slowly became a shell of her former self as vascular dementia took hold. It’s a painful, powerless feeling. Sadly, her story is not unique. Two thirds of those affected by dementia are women¹.

What is dementia – and where does Alzheimer’s fit in?^1,2,3,4

Dementia isn’t a single disease or syndrome. It’s an umbrella term used to describe a range of symptoms that affect the cognitive decline – symptoms severe enough to interfere with daily life. Alzheimer’s disease, a degenerative brain disease, is the most common cause of dementia, responsible for 60-80% of all cases. But it’s not the only one. Vascular dementia, Lewy body dementia and frontotemporal dementia are other types, each with their own patterns and causes.

Alzheimer’s typically starts with subtly misplacing words, feeling overwhelmed by tasks that once felt easy or forgetting recent events. It’s more than the occasional “Where did I put my keys?” Over time, the disease progresses, affecting mood, language and, eventually, the ability to carry out basic daily functions. These stages are referred to as early, middle and late. Late stage can even affect innate actions like swallowing. On average, once diagnosed, cognitive function declines steadily – about three points per year on the 30-point Mini-Mental State Examination (MMSE).

Diagnosis^1,4

There’s no single test for dementia. Diagnosis involves a combination of tools, including a detailed medical history, cognitive and neurological exams, and, in some cases, brain scans (MRI, CT, or PET) or lab tests. Doctors use criteria from the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) to guide the process. While it’s not always definitive, this approach helps distinguish Alzheimer’s from other causes of memory loss and confusion.

What increases your risk?^1,2,3,4,5

Dementia is caused by conditions that damage brain cells and disrupt their ability to communicate. This damage tends to occur in specific areas of the brain, which is why different types of dementia present with different symptoms. In Alzheimer’s disease, for example, abnormal protein build-up (β-amyloid) affects cells in the hippocampus – the area responsible for memory and learning – which is why memory loss is often one of the earliest signs.

Age is the strongest known risk factor. While dementia is not a normal part of ageing, the likelihood of developing it increases significantly with age – most people with Alzheimer’s are over 65. Sex also matters – women are at greater risk, with two out of every three people living with Alzheimer’s being female. This is partly due to longevity but may also involve the drastic hormonal changes (particularly oestrogen) in the menopause.

Genetics also play a role. People without a genetic predisposition have about a 13% lifetime risk of developing Alzheimer’s. But carrying one copy of the APOE4 gene increases that risk by around 30% and having two copies – one from each parent – raises it to over 50%. These inherited risk genes don’t guarantee the disease but they do raise susceptibility. There are also rare deterministic genes that directly cause Alzheimer’s, though these account for only a small proportion of cases.

Some evidence also suggests that race may play a role. Based on data compiled by the Internation Alzheimer’s Association’s Research and Education Coalition, older African Americans are twice as likely and older Latinos 1.5 times as likely to develop Alzheimer’s compared to older white adults – likely due in part to higher rates of vascular disease.

While age, sex, race and genetics are factors we can’t change, many others are within our control. The 2024 Lancet Commission on dementia prevention, intervention and care highlights 14 modifiable risk factors that could account for up to 40% of global dementia cases, pointing to the power of prevention through lifestyle and environmental changes.

The Lancet Commission Report identified 14 modifiable risk factors³:

1. Low education (early life)
2. Hypertension
3. Hearing loss
4. Smoking
5. Obesity
6. Depression
7. Physical inactivity
8. Diabetes
9. Low social contact
10. Excessive alcohol use
11. Traumatic brain injury
12. Air pollution
13. Sleep problems
14. Excessive sedentary behaviour

The report highlighted that addressing most risk factors in the mid-life had the greatest impact in delaying or preventing the onset of dementia later in life.

Nutrition and lifestyle strategies for dementia and Alzheimer’s^1,4,5

Your brain is home to around 100 billion nerve cells (neurons), each forming thousands of connections in a vast communication network. These cells need to generate fuel, process and store information, remove waste and stay in constant communication with one another. To keep all this running smoothly, your brain depends on a steady supply of nutrients, oxygen and metabolic support. This is why how you live – what you eat, how you move, how well you sleep – matters so much. It’s about protecting this complex system over time. The biological changes that lead to neurodegenerative conditions like Alzheimer’s disease don’t happen overnight. They begin quietly, often decades before symptoms appear.

Diets for dementia and Alzheimer’s^{4,5,6,7,8,9,10}

Several dietary patterns have been associated with a reduced risk of Alzheimer’s disease, particularly the Mediterranean diet and the MIND diet (Mediterranean-DASH Intervention for Neurodegenerative Delay). Brain scans show that the brain of a 60-year-old women on the Mediterranean diet looks five years younger than that of a 50-year-old women on the Western diet. A Mediterranean diet features an abundance of fruits and vegetables, nuts, seeds, fish and olive oil. Shorten with AI

The MIND diet combines principles of the Mediterranean and DASH (Dietary Approaches to Stop Hypertension) diets, with a specific focus on leafy greens, berries, whole grains and healthy fats. On the other hand, a diet that is high in processed fats and habitually high in sugar, as in a typical Standard America Diet (SAD diet), has been linked to poorer cognitive function, increased inflammation of the brain and an increased risk of dementia.Shorten with AI

When it comes to individual food components, higher intakes of saturated fats and added sugars (particularly sugar-sweetened beverages) have been linked to an increased risk of Alzheimer’s disease, while fish consumption has been associated with reduced risk, likely due to its omega-3 fatty acid content. Evidence regarding dairy is mixed: one study suggested a possible link between lactose (the sugar in milk) and increased Alzheimer’s risk, but other studies have shown no association or even potential protective effects. Shorten with AI

Findings on coffee are more mixed – moderate consumption appears to have no adverse effect and may even offer some benefit, but excessive intake could increase risk. Early studies suggest that ketogenic diets or ketone supplements may improve daily functioning and quality of life, particularly in individuals without the APOE4 gene variant – although cognitive improvements are less consistently reported.Shorten with AI

Diet may influence dementia risk through several biological mechanisms. Some of the strongest evidence links brain health to heart health. This connection makes sense, because the brain is nourished by one of the body’s richest networks of blood vessels and the heart is responsible for pumping blood through these blood vessels to the brain.

Unhealthy diets may also drive neuroinflammation, increasing oxidative stress and the activation of immune cells in the brain. Impairing the brain’s ability to clear β-amyloid and mitochondrial dysfunction can result in energy shortages for neurons, while a compromised blood-brain barrier may allow harmful substances to enter the brain.

Emerging evidence underscores the importance of the gut-brain axis and chronic inflammation in neurodegeneration. A high-fibre diet, especially rich in soluble fibre, may help reduce inflammation and support brain health. For example, a Japanese cohort study of 3,739 adults aged 40-64 found that those in the highest quartile of dietary fibre intake had a 26% lower risk of disabling dementia compared to those in the lowest quartile.

Neuroprotective nutrition in practice

A high-polyphenol Mediterranean-style diet that is moderate to low in low GI carbohydrates may offer the most neuroprotection. Practical strategies include:

• Eat a rainbow of antioxidant-rich plants. Berries, leafy greens, turmeric and herbs like rosemary contain powerful compounds that reduce oxidative stress, support brain cell function and help maintain a healthy, diverse microbiome. Nutrients like vitamin K, lutein and folate (found in spinach, kale and broccoli) have been linked to slower rates of cognitive decline.
• Feed your gut with fibre. Aim for at least 30g of fibre daily. Fibre also feeds beneficial gut bacteria, which may positively influence mood, focus and cognition.
• Focus on carb quality. Choose low glycaemic index (GI) carbohydrates that release energy slowly and help regulate blood sugar – important for long-term brain health and mood stability.
• Be consistent with omega-3s.Oily fish or seaweed provides brain-beneficial fats that reduce inflammation, support neurotransmission and may help protect against mood disorders like depression. The protein in fish also supports healthy neural communication.
• Keep saturated fat in check. Particularly from processed foods and fatty animal sources. Know your blood lipid profile – including ApoB – as elevated levels can increase vascular risk, which is closely linked to cognitive decline.
• Watch your salt intake. Excess sodium can impact blood pressure and vascular health, both of which are critical for maintaining brain integrity over time.
• Consider intermittent fasting or time-restricted eating. Approaches such as 12–16-hour overnight fasts may promote cellular repair processes (like autophagy) and support metabolic and cognitive resilience.
• Limit alcohol and dietary toxins. Minimise exposure to potential brain disruptors like heavy metals, moulds and excessive alcohol, which can increase inflammation and accelerate neurodegeneration.
• Optimise vitamin D levels. Low vitamin D is common in individuals with Alzheimer’s disease. Get levels checked and consider supplementation if needed to support brain and immune health.

Why movement matters for brain health^3,11

Regular physical activity is one of the most powerful tools we have for protecting and enhancing brain health. It improves cognitive functions such as learning, memory and problem-solving, while also helping to reduce the risk of cognitive decline and neurodegenerative conditions like Alzheimer’s disease. Exercise increases blood flow to the brain, stimulates the release of mood- and memory-enhancing neurotransmitters (like BDNF and dopamine) and supports neuroplasticity – the brain’s ability to adapt and form new connections across the lifespan. A study that followed more than 1,400 older adults over seven years found that those who engaged in higher levels of physical activity had a 39% lower risk of developing dementia, independent of other health and lifestyle factors.

To get even more brain benefits from your workouts, dual task movement is recommended. This is movement that combines moving your body while simultaneously engaging your brain – like walking while doing mental maths, dancing in a Zumba class or playing a game of tennis. Research shows this kind of activity can significantly enhance executive function and slow age-related cognitive decline.

Chronic stress, on the other hand, can take a serious toll on the brain. For example, caregivers – who often face prolonged stress – are two to six times more likely to develop Alzheimer’s disease. One of the most effective ways to lower stress? Move your body. Even a brisk walk can help reset your stress response and support long-term brain health.

Why sleep is non-negotiable for brain health^1,12,13

Sleep isn’t just rest – it’s active brain maintenance. During deep sleep, the brain undergoes a remarkable cleansing process, clearing out toxins, including beta-amyloid, the protein linked to Alzheimer’s disease. Skimping on sleep means missing this nightly rinse cycle, which over time can raise the risk of cognitive decline. A study that followed nearly 8,000 participants over 25 years found that sleeping fewer than six hours per night in midlife was associated with a 30% increased risk of developing dementia later in life.Shorten with AI

Prioritising good-quality sleep is one of the most powerful things you can do for long-term brain health. Aim for seven to nine hours per night, keep your sleep routine consistent and don’t ignore signs of sleep disorders like loud snoring, gasping or persistent daytime fatigue.Shorten with AI

Read more of Dr Linia’s expertise on nutrition in this post on anti-inflammatory diets on the FitPro blog.

References

1. Alzheimer’s Association (n.d.) What is the difference between Alzheimer’s and dementia? Available at: https://www.alz.org/alzheimers-dementia/difference-between-dementia-and alzheimers (Accessed: 21 October 2025).
2. International Coalition for Alzheimer’s Research and Education (n.d.) Evidence of racial and ethnic disparities in Alzheimer’s disease. Available at: https://icare-alz.org/evidence-of-racial-and-ethnic-disparities-in-alzheimers-disease (Accessed: 21 October 2025).
3. The Lancet Commissions (2024) ‘Dementia prevention, intervention, and care: 2024 report’, The Lancet, 404(10452).
4. Examine.com (n.d.) Alzheimer’s. Available at: https://examine.com/search/?q=alzheimers (Accessed: 21 October 2025).
5. Brandt, J., Rogerson, M. and Greger, J. (2019) ‘Preliminary report on the feasibility and efficacy of the modified Atkins diet for treatment of mild cognitive impairment and early Alzheimer’s disease’, Journal of Alzheimer’s Disease. doi:10.3233/JAD-190123.
6. Shishtar, E., Rogers, G.T., Blumberg, J.B. and Wallace, T.C. (2020) ‘Long-term dietary flavonoid intake and risk of Alzheimer disease and related dementias in the Framingham Offspring Cohort’, American Journal of Clinical Nutrition. doi:10.1093/ajcn/nqz293.
7. Ashfaq, T., Rehman, S.U. and Qureshi, M.A. (2025) ‘Association between caffeine intake and Alzheimer’s disease progression: a systematic review’, Cureus, 17(3), e80923. doi:10.7759/cureus.80923.
8. Yamagishi, K. et al. (2022) ‘Dietary fibre intake and risk of incident disabling dementia: the Circulatory Risk in Communities Study’, Nutritional Neuroscience. doi:10.1080/1028415X.2022.2045383.
9. Kivimäki, M. et al. (2019) ‘Physical inactivity, cardiometabolic disease, and risk of dementia: an individual-participant meta-analysis’, BMJ, 365, l1495. doi:10.1136/bmj.l1495.
10. Jia, J. et al. (2019) ‘Effects of vitamin D supplementation on cognitive function and blood Aβ-related biomarkers in older adults with Alzheimer’s disease: a randomised, double-blind, placebo-controlled trial’, Journal of Neurology, Neurosurgery & Psychiatry. doi:10.1136/jnnp-2019-320520.
11. Sabia, S. et al. (2021) ‘Association of sleep duration in middle age and old age with incidence of dementia’, Nature Communications, 12(1), 2289. doi:10.1038/s41467-021-22354-2.
12. Begde, A., Bhalerao, P. and Jadhav, M. (2021) ‘Does physical exercise improve the capacity for independent living in people with dementia or mild cognitive impairment: an overview of systematic reviews and meta-analyses’, Aging & Mental Health. doi:10.1080/13607863.2021.1876631.