Can a vegan diet help prevent dementia and Alzheimer’s disease?

We used to think that old-age dementia just happens to some people, but now we know there’s a lot we can do to reduce the risk. Join us as we examine the impact of eating a vegan diet on our risk of developing dementia and Alzheimer’s disease.

Our brains are dynamic, busy and demanding and use more than a fifth of our daily energy intake. But does the food you eat matter? And can it affect your risk of dementia?

Dementia is a rising global problem currently affecting 57 million people and is projected to rise to 152 million by 2050.

However, 40 per cent of cases could be prevented or delayed, according to a 2020 Lancet commission. Evidence is mounting that a healthy diet offers protection.

What is dementia?

Dementia is not a single disease but a collection of symptoms resulting from damage to the brain. Changes in the brain may occur years, or even decades, before symptoms appear.

Symptoms include permanent or recurring loss of memory, language skills, problem-solving and other cognitive abilities, and it makes the person unable to cope with daily life on their own. It can affect feelings of hunger, thirst and the ability to swallow.

Alzheimer’s disease is the most common form, but there are several other forms of dementia and it can also result from brain injuries or stroke.

The disease is a progressive one, so once it develops, it is expected to get worse over time. There is currently no cure for dementia, but some treatments can help with symptoms.

Over 900,000 people in the UK have dementia and the number is steadily rising. According to Alzheimer’s Research UK, dementia is the most feared health condition for people over 55 – more than cancer or diabetes.

Risk factors for dementia

We can’t do anything about our genes, but we can reduce the other risk factors for dementia with lifestyle and dietary changes.

Research shows that apart from genetic factors, the risk of dementia increases with rising blood lipids (cholesterol and other fats in the blood), blood pressure, body weight and diabetes.

The more risk factors you have, the higher your risk of dementia.

The Whitehall II cohort study, following 10,095 British civil servants for 32 years, found that having two or more chronic conditions was linked to a 2.4-fold higher risk of dementia.¹

Plus, the younger the onset of the condition, the higher the risk.

Obesity

Many studies show obesity in midlife increases the risk of dementia – especially for those who store fat on their tummy.

One long-term study following over 10,000 people found that being obese in mid-life increases dementia risk by 74 per cent and being overweight increases it by 35 per cent.²

Vegans tend to weigh less than meat-eaters and the EPIC-Oxford study found that they also gain significantly less weight than meat-eaters as they age.³

Diabetes

It’s been known for many years that diabetes increases the risk of heart disease and stroke, but a recent review of 28 studies found that it also increases the risk of all types of dementia by 73 per cent and Alzheimer’s by 56 per cent.⁴

Around 90 per cent of people with diabetes in the UK have type 2 variety. A vegan diet reduces the risk of type 2 by up to 50 per cent and can be used to reverse it.

Cholesterol

Having higher cholesterol levels in mid-life ups the likelihood of developing dementia by a massive 50 per cent, according to science.

A study looking at links between cholesterol and dementia in 1.8 million people over two decades found that high LDL ‘bad’ cholesterol in mid-life increased the risk of dementia more than a decade later.⁵

Again, vegans tend to have lower cholesterol levels.

Blood pressure

Another study found that a blood pressure reading of 130 or more in systolic blood pressure (the top number in your blood pressure reading) at the age of 50 was associated with an increased risk of dementia.⁶

All these health issues are tightly linked to diet – in particular to a Western-style diet high in meat, dairy, eggs, processed and sugary foods.

This kind of diet also has an undeniably negative impact on gut bacteria. This is important because a lack of ‘good’ gut bacteria, and having more of the ‘bad’ ones, means your gut wall may be letting dangerous molecules and metabolic by-products through into the bloodstream.

These molecules can then activate the immune system and this response may cause chronic inflammation.⁷ Modern science has increasingly been linking poor gut health and chronic inflammation to cognitive decline.

The Hellenic Longitudinal Investigation of Aging and Diet (HELIAD) study in Greece followed 1,000 people for three years and found that those eating the most pro-inflammatory foods were three times more likely to develop dementia.⁸ 

Meaty, fatty, sugary diets are bad news for the nervous system!

Can a vegan diet reverse diabetes and other risk factors?

The good news is these risk factors can be prevented or reversed by eating healthily and making lifestyle changes.

The Finnish Cardiovascular Risk Factors, Aging and Dementia (CAIDE) study, looking at people in their mid-50s and again when they were 70 and then 78, found that healthy dietary changes in mid-life, such as switching to healthier fats, increasing vegetables and decreasing salt and sugar, was linked to a 59 per cent lower risk of dementia.⁹ 

Individual nutrients made little or no difference – it was the whole diet that reduced the risk.

A vegan diet that’s naturally high in antioxidants, fibre and low in saturated fats helps to protect your cognitive health and can lower your risk of dementia.

Of course, this may be because vegans are less likely to be overweight or obese and may have lower cholesterol and blood pressure levels compared to meat-eaters, but that’s not the end of it!

When examining the link between diet and cognitive function, one study found that people whose mid-life diets were characterised as healthy (high in plant-based foods, low in saturated fats) had a lower risk of dementia and Alzheimer’s disease later in life compared with people with unhealthy diets rich in meat and dairy foods.

The difference was staggering – people who ate the healthiest had an 86-90 per cent decreased risk of dementia and a 90-92 per cent decreased risk of Alzheimer’s disease compared with people whose diet was the least healthy.¹⁰

A healthy vegan diet also has anti-inflammatory effects and supports the ‘good’ gut bacteria and, by so doing, helps to protect the nervous system and supports the immune system.

Diabetes is a major risk factor for dementia. Learn more about managing type 2 diabetes on a vegan diet

What foods to eat to help fight dementia

Over time, researchers pinpointed several foods and nutrients that seem to have a particularly protective effect on our cognitive health.

Vitamin E

From foods, rather than supplements. Healthy food sources of vitamin E include nuts, seeds, green leafy vegetables and wholegrains.

B – group vitamins

From wholegrains, pulses, green leafy vegetables and nutritional yeast. Add a reliable vegan source of vitamin B12, such as a supplement providing 50g daily or a higher dose twice a week.

Omega-3 fats

From ground flaxseed, chia or hemp seeds (2 tablespoons), walnuts, rapeseed oil or algae-derived supplements.

Green leafy vegetables

Green leafy vegetables are a rich source of folate, vitamin E and other nutrients linked to brain health.

They also contain carotenoids and polyphenols, plant-based molecules that have potent antioxidant and anti-inflammatory activities.

Inflammation is one of the factors thought to increase the risk of dementia later in life and diet can affect it.

Berries

Fruit with a very high flavonoid content. Flavonoids are a group of natural compounds found only in plants and research indicates they have a neuroprotective effect. Studies have discovered that people who regularly consume berries have a significantly lower risk of dementia.

Plant sources of protein

Pulses (beans, peas and lentils), nuts, seeds and wholegrains are not just healthy sources of protein, they are low in saturated fat and high in fibre – exactly what you need to lower your risk of cognitive decline.

Monounsaturated fats and vitamin supplements

It’s likely that monounsaturated fats (olive oil, avocados) and vitamin D (supplements) also have a protective effect on your nervous system, but more research is needed.

Some studies suggest low levels of vitamins D¹¹ and B12¹²  are linked to an increased risk of dementia. Ensure a regular intake of vitamin B12 and consider taking a vitamin D supplement, at least in the winter months (everyone should do this!)

It’s important to note that if you’re using multiple supplements, choose those without iron and copper as high intakes of these minerals can have a negative effect on your cognitive health.

Take iron supplements only when advised by a medical professional to avoid dangerously high iron intake.

The MIND diet and dementia

Researchers at Rush University in Chicago created a diet based on the Mediterranean and blood pressure-lowering DASH diets.

It was called the Intervention for Neurodegenerative Delay (MIND) diet and featured fruit and vegetables, whole grains, pulses, nuts and extra-virgin olive oil. It contains very little (if any) red meat, butter, pastries, sweets and fried/fast food – all are best avoided.

The MIND diet includes some fish and poultry, but studies showing how vegetarians have a lower risk of dementia provide reassurance that excluding fish from your diet is not detrimental to brain health. There are healthier and more sustainable sources of omega-3s, such as ground flaxseed, chia or hemp seeds, walnuts and algae-based supplements. Poultry is not a healthy food either as modern chickens now provide more energy from fat than protein.

The MIND diet emphasises green leafy vegetables and berries – both known to protect brain health. A study following 960 older people for nearly five years found that those who ate the most brain-healthy foods (based on the MIND diet index) had a slower rate of cognitive decline equivalent to being 7.5 years younger than those eating the least.¹³

For green leafy vegetables, the rate of decline among those consuming one or two servings a day was the equivalent of being 11 years younger compared with those who rarely or never ate green leafy vegetables. The message is clear – eat your greens!

Other factors that may reduce the risk of dementia

Regular physical activity is linked to a reduced risk of dementia.

People who are active tend to preserve their cognitive health better into old age.

You don’t have to become a professional vegan athlete, but make sure you at least take a brisk walk or dedicate 30 minutes to exercise on a daily basis.

Insomnia also negatively impacts cognition, as you probably know if you suffer from it. If it’s chronic insomnia, it may increase your risk of cognitive decline to some degree, but this varies from individual to individual.

Getting enough sleep, avoiding smoking and keeping alcohol within recommended limits are also important factors that can reduce your risk of dementia.

How can a vegan diet help to prevent dementia?

Those following a healthy plant-based diet may be less prone to some of the risk factors of dementia, such as obesity, diabetes, and high cholesterol.

If you’re vegan, you’re probably already consuming most, if not all, of the foods and nutrients from the ‘good’ list.

With a skyrocketing rise of vegan junk foods, however, it’s good to remind yourself what your body truly needs.

Simply excluding animal products from your diet will not reduce your risk of dementia alone, but a MIND diet that also excludes fish and poultry has been found to benefit brain health.

In summary, to protect your brain health, base your diet around fruit and vegetables (with plenty of berries and leafy greens), whole grains, pulses, nuts and seeds (walnuts, ground flaxseed or an algal supplement), plus vitamin B12 and vitamin D in the winter.

Plant-based diets are the healthy choice at any age. Learn more about a healthy vegan diet over 50

Featured photo © LightFieldStudios via Getty Images

References:

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