Food for thought: The best diet to beat dementia

Patrick Holford, leading nutrition expert and founder of the Food for the Brain Foundation, outlines exactly what to eat to protect your brain and prevent cognitive decline

Of all the organs in your body, your brain may be the weakest link. There is a “global brain health emergency,” says the European Federation of Neuroscience Societies.

Both our brain size and our IQ are falling, on average, says Professor Michael Crawford, director of the Institute for Brain Chemistry and Human Nutrition at Imperial College London—and it’s largely down to what you eat. The thin edge of the wedge is depression, anxiety, insomnia, forgetfulness and ultimately failing memory. Dementia affects close to a million people in the UK and 7 million in the US, about 10 percent of the over-65s in both countries.

We literally have to “upgrade” our brains—otherwise, we’re heading for a cerebral tsunami.

In the 1990s, I set up the Brain Bio Centre in London, at the Institute for Optimum Nutrition, to treat people suffering from a wide variety of mental health concerns.

Over 40 years, I’ve had the chance to study under the leading lights in mental health, including David Smith, emeritus professor of pharmacology at the University of Oxford, and Helga Refsum, professor of nutrition at the University of Oslo. Refsum’s impeccable studies of nutritional treatment have shown up to a 73 percent reduction in shrinkage of the Alzheimer’s areas of the brain in a year, compared to placebo, which is leagues ahead of any dementia drug treatments (see ‘Two nutrients that stop your brain shrinking,’ below).

I’ve pieced all the research together to bring you the ultimate brain-friendly diet as well as eight essential ways to dementia-proof your diet and lifestyle. With all we know now, it’s possible not only to prevent cognitive decline but also to enhance brain function, intelligence, memory, concentration and mood.

Feed your brain

What you eat has a massive impact on your brain health. A study in Finland and Sweden compared those with a healthy versus unhealthy diet in midlife to determine their risk of developing Alzheimer’s disease and dementia 14 years later. Those who ate the healthiest diet had an 88 percent lower risk of developing dementia and a 92 percent lower risk of developing Alzheimer’s.¹

A study following more than 30,000 people over a decade found that those with a healthy diet were about seven times less likely to have age-related cognitive decline or dementia than those with an “average” diet and about nine times less likely to develop dementia than those with an unfavorable diet.

The definition of a healthy diet was one high in fish, eggs, fruits, vegetables, legumes, nuts and tea.² These foods are hallmarks of a Mediterranean-style diet, which usually contains more fruit, vegetables, legumes, nuts and seeds as well as more fish, less meat and sometimes some wine.

Early studies on the Mediterranean-style diet reported that high adherence reduced the risk of Alzheimer’s by a third compared to low adherence.³

The most recent study conducted by researchers at Rush University Medical Center in Chicago looked at the effects of a Mediterranean-style diet called the MIND diet, with lots of vegetables and fruit. According to the researchers, “People who scored highest for adhering to the Mediterranean diet had average plaque and tangle amounts in their brains, similar to being 18 years younger than the people who scored lowest.”⁴

A similar study in Holland reported on brain volume, another indicator of dementia: “Better diet quality related to larger brain volume, gray matter volume, white matter volume, and hippocampal volume. High intake of vegetables, fruit, whole grains, nuts, dairy and fish and low intake of sugar-containing beverages were associated with larger brain volumes.”⁵

So, following a brain-friendly diet could reduce your risk of cognitive decline by up to 90 percent, stop your brain shrinking and prevent signs of brain aging, such as amyloid plaques and neurofibrillary p-tau tangles (see ‘Rooting out the cause,’ below).

Small changes, big differences

Adding one good food to your diet can make a big difference. Rush University’s research found that ticking one good food box—such as eating the recommended amounts of vegetables or fruits—reduced amyloid buildup in the brain to a level similar to being about four years younger.

In their study, the greatest result was found in those eating greens. Those in the top third of greens consumption had substantially less Alzheimer’s-related pathology than those in the lowest third.

“Doing a simple dietary modification, such as adding more greens, berries, whole grains, olive oil and fish, can actually delay your onset of Alzheimer’s disease or reduce your risk of dementia when you’re growing old,” said study author Puja Agarwal, assistant professor of internal medicine at Rush University Medical Center.

Reducing bad foods has a big impact, too. Replacing just 10 percent of ultra-processed food by weight in your diet with an equivalent proportion of unprocessed or minimally processed foods can lower the risk of dementia by 19 percent.⁶

Top brain-friendly foods

So, what are the foods most protective for your brain and cognitive health? According to a study carried out in Norway,⁷ these are some of the most important ones to include in your diet.

Fruit and veg. The more you eat, the better, though the benefits start to plateau at 500 g a day, which is about five to six servings. Carrots, cruciferous vegetables, citrus fruits, berries and mushrooms are especially good for brain health.⁸

The Rush University study found that those who ate 1.3 portions of green leafy vegetables a day, compared to less than one portion a week, had a dramatically slower decline in cognitive function, equivalent to being 11 years younger over a 10-year period.

Fish. Eating fish once or more each week can reduce the risk of Alzheimer’s by a third compared to eating fish less than once a week.⁹ The benefit peaks at about 100 g a day, which is one to two servings. Oily fish, as a source of omega-3 fats, is the best.

Olive oil and nuts. One study assigned people to a Mediterranean diet supplemented with either 1 L a week of olive oil or 30 g of nuts a day, which is a small handful, versus a control diet with low fat, and reported reduced cognitive decline with the extra olive oil or nuts.¹⁰ I favor olive oil high in polyphenols, such as Drop of Life Organic Extra Virgin Olive Oil.

Chocolate. The benefit peaks at 10 g, or about three pieces, and dark chocolate (at least 70 percent cacao), which is lower in sugar, is likely better, as sugar is a strong contributor to cognitive decline. Other studies have linked cocoa, a rich source of flavanols, to improved cognition.¹¹

What makes a food brain-friendly? The foods listed above are rich sources of one or more of the following critical nutrients:

• Antioxidant vitamins (C and E)
• Flavanols and other phytonutrients
• Vitamin D
• Omega-3 fats
• Folate and other B vitamins
• Phospholipids and choline

How to follow the brain-friendly diet

Bearing all this in mind, the following steps are keys to a diet designed to protect brain health and reduce your risk of cognitive decline.

Eat essential fats and phospholipids

• Eat an egg a day, or six eggs a week. If possible, choose free range and organic. Boil, scramble or poach them, but avoid frying.
• Eat a tablespoon of seeds and nuts every day. The best seeds are chia, flax, hemp and pumpkin (all higher in omega-3). They’re delicious sprinkled on cereal, soups and salads. The best nuts are walnuts, pecans and macadamia nuts, but all nuts are good sources of protein and minerals.
• Eat coldwater, oily, carnivorous fish. Have a serving of herring, mackerel, salmon or sardines two or three times a week (limit tuna, unless identified as low in mercury, to three times a month). Vegans need to supplement with algal omega-3 DHA as well as choline or lecithin capsules or granules rich in phosphatidylcholine.
• Use cold-pressed olive oil. It’s best for salad dressings and other cold uses, such as drizzling on vegetables instead of butter.
• Replace frying with steam frying. Steam fry by cooking in olive oil, coconut oil or butter, e.g., for onions and garlic, then adding a watery sauce, such as lemon juice, tamari or water, to “steam” vegetables, perhaps with tofu, fish or chicken.

Eat slow-release carbohydrates

• Eat whole foods—whole grains, lentils, beans, nuts, seeds, fresh fruit and vegetables—and avoid all white, refined and overprocessed foods, as well as any food with added sugar.
• Snack on fresh fruit, preferably apples, pears and/or berries, especially blueberries.
• Eat less gluten. Try brown rice, rye, oats, quinoa, lentils, beans or chickpeas.
• Avoid fruit juices. Eat fresh fruit instead. Occasionally have unsweetened Montmorency cherry juice or blueberry juice (made from unsweetened concentrate).

Eat antioxidant- and vitamin-rich foods

• Eat half your diet raw or lightly steamed.
• Eat two or more servings a day of fresh fruit, including one of berries.
• Eat four servings a day of dark green, leafy and root vegetables such as broccoli, broccolini (tenderstem broccoli), kale, spinach, watercress, carrots, sweet potatoes, brussels sprouts, green beans or peppers, as well as mushrooms. Choose organic where possible.
• Have a serving a day of beans, lentils, nuts or seeds, all high in folate.

Eat enough protein

• Have three servings of protein-rich foods a day if you’re a man, and two if you’re a woman.
• Choose good vegetable protein sources, including beans, lentils, quinoa, tofu or tempeh (soy) and “seed” vegetables such as peas, broad beans and corn.
• For animal protein, choose lean meat or preferably fish, organic whenever possible.

Eat gut-friendly foods and fiber

• Add sauerkraut, kimchi, live yogurt, kefir, kombucha, fermented pickles and some unpasteurized soft cheese to your diet.
• Add chia seeds to oat-based cereals.
• Limit or avoid wheat. Have oatcakes instead of bread.
• Eat oats, beans, nuts, seeds, whole fruit and vegetables, having four servings of vegetables a day, raw or lightly steamed.
• Eat prebiotic-rich Jerusalem artichoke, garlic, leeks, onions, asparagus, barley and oats.

Avoid harmful fats

• Minimize your intake of cheese, fried or processed food, and burnt saturated fat on meat.
• Minimize your consumption of deep-fried food. Poach, steam or steam-fry food instead.
• Minimize your intake of refined vegetable oils high in omega-6 (principally soybean oil, corn oil and sunflower oil).

Limit sugar, caffeine and alcohol

• Avoid adding sugar to dishes, and avoid foods and drinks with added sugar. Keep your sugar intake to a minimum, sweetening cereal or desserts with fruit.
• Avoid or considerably reduce your consumption of caffeinated drinks. Don’t have more than one caffeinated drink a day. Tea is preferable to coffee, and green tea has less caffeine and more polyphenols.
• Drink alcohol infrequently, preferably red wine, up to one small glass (125 g) a day.
• Have up to three pieces of dark chocolate, minimum 70 percent cacao, or drink unsweetened cacao with milk or plant milk.

Rooting out the cause

There are two hallmarks of Alzheimer’s, which accounts for two-thirds of dementia. The first is “neurofibrillary tangles”—think wires in a mess—which are linked to the accumulation of an abnormal protein called p-tau.

The second is a buildup of abnormal amyloid protein resulting in amyloid deposits, or plaques. These deposits are found mainly in the synapses, or junction points where two brain cells meet.

Plaques and tangles are the main targets for the new generation of dementia drugs. The trouble is the anti-amyloid drugs don’t work that well, despite lowering amyloid, and have terrible side effects. One-third of patients get brain bleeding and swelling, which can be fatal.

But is the cause of dementia the amyloid plaque or the p-tau-induced tangles? Consider your teeth. Is the cause of tooth decay plaque? Sure, flossing your teeth and getting the plaque scraped off by the dental hygienist helps, but what causes the plaque?

The answer is a bad diet—in this case, one high in sugar and low in fiber. The same concept applies to Alzheimer’s, which is as preventable as tooth decay with the right diet and nutrition.

The best fruit and veg to eat for your brain

Which vegetables pack the biggest punch of polyphenols and antioxidants and are also low in sugar or low-GL?

GL, which stands for glycemic load, is the measure of the total glucose load in your bloodstream—both how high your blood glucose rises and for how long when you eat carbohydrate. A high-GL diet has been linked to cognitive decline.¹

Taking all these factors into account, these are the 14 best-rated fruit and veg. The optimal intake for brain protection is five to six servings a day. Half a plate of a main meal counts as two. A handful of berries counts as one.

So, if half your plate for two main meals is vegetables, and you have berries with breakfast and a piece of fresh fruit or some broccoli heads or carrots dipped in hummus as a snack, or half an avocado with some high-polyphenol olive oil, you’ve had six servings.

Three stars indicate a food is the best in that category, two indicate it has high value, and one indicates it has good value. Examples: Beetroot has a low GL, but olives have the lowest GL. Red onions have good antioxidant value, but blueberries and strawberries have the highest antioxidant value.

Eight secrets to upgrade your brain

Here are eight essentials for a brain upgrade which, if you do them all, will dementia-proof your diet and lifestyle.

Eat a low glycemic load (GL) diet

Avoid sugar and refined (white) carbs, like white bread, rice and pasta. Eat whole foods, whole fruit instead of fruit juice, and lots of vegetables.

Increase brain fats

Seafood provides both brain-friendly omega-3 and vitamin D. Eggs provide essential phospholipids. Aim for three servings of fish and six eggs a week.

Supplement with vitamin D

Regular sunshine can help you make the vitamin, but it may not be enough, especially in the winter months. Get a blood test and adjust accordingly.

Supplement B vitamins

Your brain depends on B vitamins, especially vitamin B6, folate (found in greens) and B12, found only in animal foods. B12 becomes harder to absorb when you age. Supplementing 500 mcg has cut brain shrinkage in those at risk by half.

Up antioxidants and polyphenols

These are found in higher amounts in fresh organic vegetables and fruits, especially berries, herbs and spices, and in dark chocolate. Have five to seven servings a day.

Eat for a healthy gut

Eating whole foods rich in fiber, including whole oats and chia seeds plus a wide variety of raw or steamed vegetables, nuts, seeds and fruit, keeps your gut healthy.

Keep your body active

Aim for half an hour of physical activity every day. Yoga, Pilates and strength training maintain or build muscle mass, which promotes brain mass too.

Activate your mind

Use it or lose it. Learn new things, engage with brain games, don’t veg out on too much mindless telly. Learning a language, a musical instrument or any new skill is great for your brain.

Sleep well and stay calm

Get seven to eight hours of sleep a night and learn how to control your stress levels. Stay away from too much coffee (and sugar) after noon.

For more individualized advice, take the free online Cognitive Function Test at foodforthebrain.org, which shows you exactly what’s driving your dementia risk and what to do to optimize your brain function and memory to reduce your risk of losing them later in life.

Two nutrients that stop your brain shrinking

Research shows that both omega-3 fish oils and B vitamins can reduce the risk of dementia. But not all trials have been successful. Now four research groups, at the University of Oxford and in Holland, China and Sweden, have found that neither nutrient can work without the other.

The discovery was hailed as “a major step toward Alzheimer’s prevention” by pharmacology professor David Smith. He found that supplementing with B vitamins (B6, B9 and B12), at higher levels than can be achieved through diet, in those with sufficient levels of omega-3 fats stopped accelerated brain shrinkage, the hallmark of Alzheimer’s.¹

“The effect is greater than that of any drug treatment to date,” said Smith.

A Dutch trial has reported no benefit from the B vitamins in those with low omega-3 status, but a massive improvement in cognition in those with sufficient omega-3 levels.²

A Swedish trial giving omega-3 fish oils to older people found the group with sufficient vitamin B, indicated by a low level of blood homocysteine, showed three times the clinical improvement reported from the recent lecanemab anti-amyloid drug trial.³

A Chinese trial found the greatest improvement in those supplementing both omega-3 and vitamin B9 (folate).⁴

Almost half of all people over 65 have high homocysteine,⁵ which increases the risk of dementia by up to 10 times, according to recent research.⁶

It’s the combination of enough omega-3 and B vitamins that cuts the rate of brain shrinkage by up to 73 percent.

I usually recommend a daily dose of 1,000–4,000 mg omega-3 (EPA and DHA), 200–800 mcg folate, 20–40 mg B6, and 10–500 mcg B12, depending on individual needs.

My charity, foodforthebrain.org, offers a home test kit that measures your homocysteine level (above 11 mcmol/L means brain shrinkage) and omega-3 index (8 percent or more means you’ve optimized your intake of omega-3) to help you tailor your diet and supplement program.

Adapted from Upgrade Your Brain: Unlock Your Life’s Full Potential by Patrick Holford, available now (Thorsons, 2024, Trade Paperback, £16.99)

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