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

Most people have never heard of homocysteine, and that’s a scandal.

There is an amino acid called homocysteine circulating in your blood, and high levels are considered a risk factor for the development of dementia. Lowering homocysteine is easy. The hardest part is finding out about it.

It’s no secret, and it’s not ‘alternative’ medicine: there is a wealth of scientific literature describing the link between homocysteine and dementia.

In the literature is where this information mainly stays.

Because elevated homocysteine (Hcy) can damage the walls of blood vessels, it is also a risk factor for cardiovascular disease and stroke, and a few other chronic health conditions.

It is surprisingly easy to lower blood levels of Hcy, thereby reducing your likelihood of developing dementia and other conditions associated with this amino acid. You just need a regular intake of certain B vitamins, namely vitamin B12 (cobalamin), folate (B9) and vitamin B6 (pyridoxine).

“Plasma concentrations of homocysteine can be lowered by dietary administration of B vitamins.” (Smith et al 2010)

What is homocysteine?

Hcy is created during the metabolism of the amino acid methionine to cysteine. This process is regulated by the trio of B vitamins working as cofactors.

Although high Hcy — aka hyperhomocysteinaemia — can be caused by a rare genetic defect, in the vast majority of people the level of circulating Hcy is determined by the amount of these three B vitamins in the diet.

Homocysteine and the shrinking brain

One of the characteristics of dementia is brain atrophy, where parts of the brain start to shrink.

Hcy is implicated in brain atrophy, affecting the hippocampus in particular. This is the area of the brain most important for memory. The higher the Hcy, the greater the level of atrophy, as evidenced by MRI scans of elderly people.

Some brain shrinkage is normal with ageing, even in people without cognitive impairment. It’s the speed of the atrophy which is relevant, being an indication that something is amiss.

Mild cognitive impairment (MCI) is considered the pre-dementia stage, and this is when atrophy starts to increase, and then accelerate, as MCI turns into Alzheimer’s disease.

The B vitamin effect

Perhaps the best known study into the relationship between Hcy and B vitamins is the VITACOG trial. This 2010 study was carried out by Oxford University researchers in the UK, and published in The Proceedings of the National Academy of Sciences of the United States of America.

This randomised, double-blind study found that high-dose vitamin B supplementation significantly slowed down the rate of cognitive decline. Of a group of 168 people with MCI, half were given B12 (0.5mg), folic acid (0.8mg) and B6 (20mg), and the other half received a placebo, for a period of two years. They all had cranial MRI scans at the beginning and end of the two year period.

At the end of the trial, the B vitamin group were found to have 53% lower Hcy than the placebo group. They also scored significantly better in memory and cognitive function tests. Those given a placebo, on the other hand, experienced a significant increase in Hcy levels over the 2-year period.

The researchers concluded that:

“The accelerated rate of brain atrophy in elderly with mild cognitive impairment can be slowed by treatment with homocysteine-lowering B vitamins.”

Get your B vitamins here!

There are a few points to note about the sources and availability of the homocysteine-lowering B vitamins.

Vitamin B6 is found in many foods, and deficiency is an unlikely problem for most people, although the elderly are considered a more vulnerable group.

Lack of B12 and folate is more likely, however, and these are the ones to watch out for because deficiency of both is commonly found in patients with neurological and psychiatric disorders.

If your aim is to secure an adequate supply of all three vitamins, bear in mind that the best sources are natural, minimally processed foods. Note that grains — wheat, corn, barley, rice — do not make an appearance in the table, despite the fact that they are widely consumed dietary staples. These are nutrient-poor foods overall and best not relied upon.

To obtain a good supply of folate (which is called folic acid when it is provided in supplement form), you need to ensure a regular supply of leafy green vegetables. My advice is to eat a portion every day, and eat it cooked, because cooking releases more nutrients. (See my article on raw versus cooked for more information on this subject.)

The last major takeaway from the above table is that you have to eat animal-source foods to receive any vitamin B12 at all, making this vitamin the trickiest of the trio. It is made exclusively in the gut of animals, by bacteria, and then migrates from gut to muscle. A water-soluble vitamin, B12 is crucial to the brain and nervous system, red blood cell formation and DNA.

Effects of B12 deficiency

Unsurprisingly, memory problems and slow mental processes are the most commonly reported cognitive problems associated with deficiency of this vitamin. Alzhiemer’s, vascular dementia and Parkinson’s are also associated with low levels of this vitamin.

There are two groups of people most likely to be B12 deficient: non-meat eaters, especially vegans, and the elderly.

Although vegetarians eat dairy foods and eggs, the quantity of B12 is quite low in these foods, and the absorption rate is not great either. However, they still tend to have higher levels of B12 than vegans, who eat no animal produce at all.

If you are vegetarian or vegan, it is essential that you take B12 supplements. And if you are over 60, you may also be at risk. Older people who are B12 deficient are more likely to experience brain atrophy, or decrease in brain volume, which is likely to lead to cognitive impairment.

It is estimated that 10%–15% of people over the age of 60 have vitamin B12 deficiency. This deficiency is attributed to high prevalence of gastric atrophy among the elderly. Gastric atrophy is a condition that arises when the lining of the stomach becomes inflamed, usually as a result of an infection caused by the bacterium Helicobacter pylori. The result is malabsorption.

Other causes of B12 deficiency include pernicious anaemia, smoking and certain medications, especially Metformin and antacids.

Shortage of this vitamin can take several years to become apparent. That is because the adult body stores enough B12 to last 3–5 years, although deficiency can arise within just a year if stores are low to start with.

Severe deficiency causes irreversible damage to the brain and nervous system and can lead to dementia and demyelination. Demyelination is the deterioration of the myelin sheath, the protective layer around nerve cells.

All three B vitamins have a close metabolic relationship, and regulation of Hcy depends on a regular intake of all three.

Why the big secret?

There are no drugs that can lower excessive Hcy— which is probably why most people have never heard of it. As ever, you just have to follow the money. In this case, there isn’t any.

Scottish doctor and author, Malcolm Kendrick, calls this absence of medical interest a “deafening silence”. As he succinctly explains:

“Vitamins cannot be patented; therefore any profit margin is far too puny to be of interest to them. Which means that there will be no funding from the pharmaceutical industry to support any further research into B vitamins.”

That’s about the long and the short of it.

Testing for homocysteine

It is scandalous that homocysteine is not widely known, and equally as scandalous that blood tests are not routinely recommended. Determining your Hcy status is as easy as a simple blood test that you can do at home.

If you’re in the UK, don’t expect your GP to arrange a test for you. (Though you can always ask!) Your alternative option is to arrange a private test. For details of how to go about this, see York Laboratories or Genova Diagnostics. Below is a sample report from York Laboratories. As you can see, it’s pretty straightforward.

If you are outside the UK, see your healthcare provider, or have a look at the Genova Diagnostics website.

High homocysteine is highly prevalent, and easily treatable. However, although treatment with B vitamins can reduce the rate of brain shrinkage in people with elevated Hcy, treatment appears to be effective only before dementia takes hold.

“Treatment is likely to be more beneficial in those whose brain shrinkage has not yet reached critical levels and in those who do not yet have dementia.” (de Jager)

But why wait until you develop the pre-dementia stage of mild cognitive impairment? Dietary modifications that ensure a consistent and plentiful supply of brain nutrients, including the B trio, are easy to implement, and should form a life-long habit.

High Hcy is by no means the only dietary link with dementia — just see the list of articles about diet and brain health below. However, it is clearly a very important one.

Last word

There is hope. Just this year (2018), the Journal of Alzheimer’s Disease published a Consensus Statement, which was the conclusion of a panel of experts after examining all the research. They state:

“We conclude, from the analysis of published findings…. that raised tHcy is a strong and modifiable risk factor for cognitive impairment and dementia.” (Smith et al 2018)

The researchers end by stating that screening for raised total Tcy should be carried out in memory clinics, and people found to have high levels should be offered supplementary B vitamins. Apparently, this is something that already happens in Sweden.

Let’s hope the rest of the world catches up soon.

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?

Read and share my other articles on diet and mental health:

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

Your brains are in your belly, and that’s good for your mental health.

How to manage your stress by changing your diet.

Is gluten messing with your mind? Find out now.

How to beat depression with vitamin D

How gut bacteria can lift depression. Be sure to feed them well.

Alzheimer’s disease and the sugar connection.

Thinking of going vegan? Read this first.

The link between diet and depression: 5 important facts

Feed Your Brain

Exploring the link between diet and mental health

Maria Cross MSc

Written by

I’m a nutrition science writer, specialising in diet and mental health. Subscribe to for free brain food guide. @MariaXCross

Feed Your Brain

Exploring the link between diet and mental health