How to stop Alzheimer’s before it begins

Four dietary changes that can slow down or block the pre-dementia stage.


Mild cognitive impairment — MCI — is a pre-dementia condition and an early warning sign of what may follow. And although dementia cannot be reversed once it has taken hold, MCI can be stopped in its tracks.

Alzheimer’s is the most common form of dementia, and a disease that strikes fear into us all. Numbers of people affected continue to soar, and early-onset diagnosis is no longer a rarity.

There is a mistaken but widespread belief that we are all helpless victims of cruel fate and random DNA, marching through our lives towards a preordained conclusion. Yet that is far from true. As the Alzheimer’s Society points out,

“Many people fear that Alzheimer’s disease in the family may be passed on to children and grandchildren. In the vast majority (99 per cent) of cases, this is not so.”

Instead, the evidence suggests that developing dementia is largely a matter of what you eat and drink.

Below are four dietary changes that can play a significant role in maintaining the health of the ageing brain.

1. Lower your homocysteine

Never heard of homocysteine? That’s you and most everyone else. It’s an amino acid, and if you have high levels of this amino acid circulating in your blood, you are at increased risk of developing dementia (and cardiovascular disease).

The most important area of the brain, as far as memory is concerned, is the hippocampus. High homocysteine is associated with a small hippocampus, and is an established risk factor for brain shrinkage (atrophy), and the development of MCI and Alzheimer’s.

The first step is to find out if you have high homocysteine, so get yourself tested. If you do, and you have, the second step is to lower that homocysteine. The only way to do so — and it’s incredibly easy — is to ensure adequate levels of three important B vitamins: B12, folate and B6.

It’s a simple equation. High levels of this trio of vitamins equal low homocysteine; low levels equal high homocysteine.

Deficiency of B6 is uncommon, as this vitamin is widely distributed in food. Folate, on the other hand, is less common, and you need to eat plenty of leafy green vegetables, such as broccoli, kale, spinach, cabbage and Brussels sprouts to ensure adequate intake.

What is “plenty”? There’s no official definition, in this case, but as far as I’m concerned, it’s one large helping a day, most days. This dietary strategy also ensures a good supply of carotenoids, plant ingredients that feature in point 3 below. Double reason, therefore, to eat your greens.

Vitamin B12 is the tricky one, the one most likely to cause a rise in homocysteine if it’s missing from your diet.

This vitamin is found only in animal-based foods, especially meat and fish. Even then, the absorption rate is only about 50%. Anyone avoiding these foods absolutely must take supplements.

They are not the only ones: anyone over the age of 60 is also at risk.

Large surveys in the US and UK have found that around 6% of people over 60 are vitamin B12-deficient, and this percentage increases with age.

Trials have also shown that homocysteine-lowering treatment with B vitamins in elderly people with cognitive impairment:

“markedly slows the rate of whole and regional brain atrophy and also slows cognitive decline.” (smith et al 2018)

In 2018, a panel of experts wrote a consensus statement on the subject, in Journal of Alzheimer’s Disease, stating:

“Screening for raised tHcy (homocysteine) should be carried out in memory clinics and those with raised tHcy should be offered supplementary B vitamins. Such a procedure already occurs in Sweden.”

If you would like to know more about homocysteine, B vitamins and dementia, read my full article on the subject — see link below.

2. Cut out sugar

Sweet, but not innocent

This dietary step is a must, if you are worried about your memory. Everyone knows sugar is ‘bad’ and makes you fat, but that is just the tip of the sugar-coated iceberg. Sugar negatively impacts the human body, and in particular the brain.

There is a strong connection between dementia and type 2 diabetes, which of course is a blood sugar disorder. The hippocampus — an important brain area for memory — is highly sensitive to variations in glucose levels, and people with type 2 diabetes usually have smaller hippocampal volume than people without the condition.

“T2DM (type 2 diabetes) has long been shown to be associated with dementia

That is why Alzheimer’s is sometimes referred to as type 3 diabetes. Over 80% of people with Alzheimer’s disease have either type 2 diabetes or abnormal blood sugar levels. There are several explanations for this. One is that high insulin, a hormone the body secretes to manage sugar in the blood, can interfere with neurons and affect cognitive function, including memory and concentration.

When you consume sugary foods and drinks, the sugar enters the blood as glucose. Large amounts of glucose mean greater vulnerability to a process called glycation. Glycation is a process whereby certain proteins become damaged, resulting in the creation of advanced glycation end-products (AGEs).

These AGEs can prevent neurons from working properly. Research has found that the brains of people with Alzheimer’s disease have high levels of these AGEs, compared to people without the disease. AGEs contribute to the formation of amyloid plaques — a characteristic of the brains of people with Alzheimer’s.

So keep blood sugar under control, and do everything you can to prevent the development of type 2 diabetes; it’s a manageable disorder.

3. Eat more colour


Preventing dementia is largely about protection from damage. That is where certain plant foods come in. It’s time to go back to eating your greens. And your reds and oranges.

The brain is full of fat, especially polyunsaturated fats, which makes it vulnerable to a process called oxidation. You know how certain cooking fats can go rancid; well, something similar can happen to the fat in the brain. It’s not a nice thought, I know.

Oxidation occurs in early Alzheimer’s.

“There is growing evidence that oxidative and inflammatory damage contribute to the pathogenesis of Alzheimer disease as well as MCI and age-related cognitive decline” (Johnson, 2012)

This is where carotenoids come in. Carotenoids are specific antioxidants found in leafy greens and coloured fruits and vegetables, and which protect polyunsaturated fats from oxidation in the brain.

You’re probably already familiar with beta carotene, famously abundant in carrots. But there are other carotenoids, some of which are especially important for the brain, including lutein and zeaxanthin.

Lutein and zeaxanthin are the dominant carotenoids in the human brain. The consumption of foods rich in these two carotenoids is associated with slower rates of age-related decline and improved cognitive function.

By the same token, both of these carotenoids have been shown to be depleted in people with MCI and Alzheimer’s.

Carotenoids are plant chemicals with a red/orange/yellow pigment. They are also found in dark leafy greens such as spinach and kale (the green pigment camouflages the red). These are the same foods that provide you with folate, to lower your homocysteine levels. Perfect.

Here are some good sources of both carotenoids:

· Kale

· Spinach

· Brussels sprouts

· Broccoli

· Carrots

· Pumpkin and squash

· Red peppers

· Yellow peppers

· Red grapes

· Melon

· Kiwis

4. Eat fish. Eat lots of fish

Dolphins are brainy

If you haven’t already (and from what I can tell, not many people have), now’s the time to develop a taste for fish, especially oily fish and seafood. There’s something about this food that is perfect for strengthening human health. That something is a fatty acid called docosahexaenoic acid, or DHA.

DHA is a major component of the human brain, but if you don’t eat any, you won’t get any. True, you’ll get a small amount from eating free-range eggs and meat, and a tiny amount (if any) from eating nuts and seeds. But the fact is that the only meaningful source of DHA is oily fish and seafood.

Best direct sources of DHA are:








Tuna (not tinned)

DHA is involved in numerous functions, including memory.

Make fish a regular habit, because it may help prevent Alzheimer’s — but won’t have any effect once the disease takes hold. Eating fish is associated with a lower risk of developing Alzheimer’s, but when the disease has progressed to neuron loss it no longer has any effect.

However, when it comes to mild cognitive impairment, it’s a different matter. Early trials show improvement in cognitive impairment in individuals with MCI, when given fish oil supplementation. Fish oil supplements are a good alternative if you really can’t stomach eating fish.

“While insufficient to draw firm conclusions, the results of these studies clearly emphasize the importance of exploring the potential of n-3 pufa (fish oil) to slow or prevent cognitive decline in the earliest preclinical phase of AD (Alzheimer’s disease).” (Calon, F., 2011)

More clinical trials are required, but as researchers writing in 2013 in Advances in Nutrition state:

“We are getting closer to providing evidence-based recommendations on fish and fish oil intake to facilitate memory function during old age. In the meantime it is advised to follow the general CDC* dietary recommendations of 2–3 fish meals per week or the equivalent intake of long chain n–3 fatty acids, particularly DHA.”

*Centres for Disease Control and Prevention

The human brain evolved on real, natural foods. These are the foods we have consumed for hundreds of thousands of years; they drove the rapid expansion of the brain throughout evolution. We may have lost our taste for many of them, with the development of industrial food ‘products’, but human biology still demands those same nutrients that nature has always provided.

Feed your brain with the fuel that makes it work.

I started the publication Feed Your Brain because I saw a real need to highlight the link between diet and mental health. If you can fix your body through diet, why not your brain?

Here are some more articles on diet and dementia:

Why you need cholesterol for your mental health

How intermittent fasting with exercise can boost your brain

How eating more fat can improve your memory

Alzheimer’s disease and the sugar connection.

How three ordinary B vitamins could save you from Alzheimer’s