Elevated Homocysteine – A Risk Factor for Alzheimer’s Disease?

High homocysteine in the population is associated with a doubling of the risk of developing Alzheimer’s”, commented David Smith, the Professor Emeritus of Pharmacology at the University of Oxford, on a recent BBC Radio 4 programme looking at how supplements that lower the levels of the amino acid homocysteine could help to slow the onset of Alzheimer’s disease.

Research surrounding Alzheimer’s disease is very rarely out of the news, especially in the past few years.

Why? Because the condition that has a profound ability to leave people with a feeling of ‘no hope’ is the subject of ongoing research suggesting that it can, in fact, be a preventable disease if the correct guidelines and protocols are followed.

Alzheimer’s disease is multi-factorial in terms of associated risk factors, in this article we are going to concentrate on just one of these; elevated levels of homocysteine in the blood.

What is Homocysteine?

Homocysteine is a naturally occurring amino acid that is produced as part of the methylation cycle and is, therefore, an important indicator of methylation status, ie. how efficiently you are methylating.

For those of you who aren’t familiar, the methylation cycle is one of the body’s most important chemical processes that occurs thousands of times a second in every cell and organ in the human body. Methylation is a process that is vital for our health and wellbeing and can be simply defined as the addition of a methyl group, or ‘CH3’, to many chemical compounds in the body.

One important aspect of this cycle is the conversion of homocysteine to two substances called SAMe (S-adenosyl methionine) and glutathione. Both SAMe and glutathione have health-promoting effects. Specifically, SAMe helps to prevent depression, arthritis, and liver damage. Glutathione is a powerful antioxidant and detoxifying agent that helps to slow down ageing.

The diagram below demonstrates that it is essential for the inflammatory radical homocysteine to be rapidly transformed into the beneficial amino acid methionine, otherwise elevated levels will be left in the blood which can start a cascade of dangerous inflammatory responses. Both shortage of methyl groups from diet or genetic factors can potentially inhibit this conversion process.

methyl group cycle

Alzheimer’s disease

Alzheimer’s disease is a cognitive related condition that causes problems with memory, thinking and behaviour. It gradually gets worse over time and the symptoms can vary greatly. There are believed to be around 520,000 people in the UK currently suffering from Alzheimer’s disease.

The Alzheimer’s Society summarise the progression of Alzheimer’s disease as the following:

“During the course of the disease, proteins build up in the brain to form structures called ‘plaques’ and ‘tangles’. This leads to the loss of connections between nerve cells, and eventually to the death of nerve cells and loss of brain tissue. People with Alzheimer’s also have a shortage of some important chemicals in their brain. These chemical messengers help to transmit signals around the brain. When there is a shortage of them, the signals are not transmitted as effectively.”

Risk Factors associated with Elevated Homocysteine and Alzheimer’s disease

To briefly summarise the role of elevated homocysteine on being a possible cause of Alzheimer’s disease, the UK Charity ‘Food for the Brain’ recently reviewed the science behind this evidence:

“Homocysteine is an indicator of disrupted methylation, which leads to raised levels of amyloid and tau proteins that are central to the formation of neuritic plaques and neurofibrilliary tangles found in the Alzheimer’s brain. Raised homocysteine leads to increased oxidative stress and damage to the blood-brain barrier. It also impairs circulation by increasing cerebrovascular damage. The evidence for homocysteine and disrupted methylation being causal to the neurodegeneration seen in AD is further strengthened by the recent clinical trial evidence showing homocysteine-lowering B vitamin treatment markedly reducing shrinkage in the medial temporal lobe.”


 A primary cause of all chronic diseases is ‘excess inflammation’. Inflammation is a normal aspect of daily metabolic activity and without it we would be dead. It is essential for cell turnover, renewal and all body processes that permit homeostasis and ultimately life.

The problem in the Western World of today is that by virtue of several factors, including poor diet and lifestyle, most of us have higher readings of inflammation in our bodies than is considered to be healthy. This is something that clearly needs to be addressed.

Elevated homocysteine levels in the blood play a key role in increasing levels of excess inflammation.

High blood level of homocysteine promotes higher blood levels of arachidonic acid and prostaglandin E2, which are chemicals that your body uses to promote inflammation. While inflammation is necessary for healing in the short term, chronic inflammation can cause lasting damage and is a precursor to chronic diseases, namely Alzheimer’s disease in this circumstance.

Brain atrophy

Brain atrophy (mass tissue loss/shrinkage) is rapidly increased when an individual has Mild Cognitive Impairment which can potentially progress towards Alzheimer’s disease. Homocysteine is a key factor in the increase of brain atrophy when blood levels of the amino acid are elevated, as the following research suggests:

“In the elderly, the brain shows significant progressive atrophy. The atrophy occurs even in cognitively healthy subjects but is much accelerated in patients suffering from Alzheimer’s disease. An intermediate rate of atrophy is found in people with mild cognitive impairment (MCI). Since the rate of brain atrophy is more rapid in subjects with MCI who convert to Alzheimer’s disease, it is important to identify factors that determine the rate of atrophy since reducing the rate of atrophy is likely to slow the conversion to Alzheimer’s disease” –

Genetic Predisposition

Some individuals develop elevated levels of homocysteine in the blood because of a certain genetic predisposition. The Methylenetetrahydrofolate reductase (MTHFR) gene produces an enzyme that can help to regulate levels of homocysteine in the body. If there is a genetic mutation in this particular gene then this process may not be carried out efficiently. The MTHFR genetic mutation is the most common inherited risk factor associated with elevated homocysteine levels.

Lowering Homocysteine Levels

Whether an individual’s homocysteine levels are elevated because of genetic, lifestyle or dietary reasons, a proactive course of action to satisfactorily address this is available. And the key factors to address are:

B Vitamins

Insufficient ‘methyl donor’ foods ( nutrients that support the methylation cycle) are likely to elevate homocysteine levels and vitamin B6, folic acid and vitamin B12 are all excellent methyl donors. So eating a good diet is, as always essential. Stress and excess alcohol consumption (for example) place a greater burden on our B vitamin supply, quite literally ‘burning’ up our reserves. Illness, injury and genetic dispositions can all affect the ability of our body to efficiently utilise vitamins including B-Vitamins.

Each of the B Vitamins is generally to be found in plentiful supply in a good diet; for example Vitamin B6 can be found in meat, whole grains, cabbages, legumes, green vegetables etc. However vegans and vegetarians are often at risk of vitamin B12 deficiency as the vitamin is mainly found in animal based foods such as meats and offal.

The lower your vitamin B status the higher your blood level of homocysteine will be, research has indicated. This is because these vitamins are essential cofactors of key enzymes related to the metabolism of homocysteine, any deficiency of these vitamins would impair the activity of these enzymes and lead to the accumulation of homocysteine in the blood.

Through slight dietary changes and possible B vitamins supplementation, the breakdown of homocysteine to SAMe and glutathione can become more efficient meaning blood levels of the amino acid decrease – this is just one of the components that reduces the likelihood of excess inflammation and brain atrophy.

Therefore consider supplementing as appropriate, or increasing your dietary intake, of the following:

  • Folate
  • Vitamin B12
  • Vitamin B6
  • Vitamin B2

(Please find the relevant Cytoplan products listed below)

Relevant Research

Recent research has demonstrated that through supplementing B vitamins, as suggested above, elevated homocysteine levels in the blood and the incidence of brain atrophy can be reduced. Here are just a couple of pertinent items of research relevant to this area of study:

1) US National Library of Medicine – “Treatment with B vitamins for 24 months significantly slowed the rate of brain atrophy. After adjustment for age, the rate of brain atrophy per year was 29.6% less in the active treatment group compared to the placebo group. Additional adjustment for the above-mentioned variables marginally changed the decrease to 27.1%. If we confined the analysis to the biologically compliant subjects, the effect of treatment was slightly greater with a reduction in atrophy rate of 31.1% in the active treatment group compared to the placebo group.”

2) A VITACOG trial – “studied the effect of high doses of folic acid, vitamin B6 and vitamin B12 on brain shrinkage in 168 volunteers with mild memory problems (mild cognitive impairment). The two year study found that rates of total brain shrinkage were slower in those taking high dose B vitamin supplements, although this was most marked in people with poor vitamin status, i.e., those who started the study with high levels of the amino acid homocysteine in their blood.”

Dietary Recommendations for Cognitive Health

As always, a healthy diet and lifestyle is essential to good health. Here are some significant dietary changes that can be made to increase and maintain cognitive health:

  • Encourage a diet high in fruit and vegetables – lots of fruit and vegetables across ‘the colour spectrum’ daily for antioxidants, vitamins, minerals and good fibre
  • Avoid saturated fat and fast-acting carbohydrates – avoid excess saturated fats such as animal fats, avoid all trans fats, avoid processed carbohydrate foods
  • Eat meats and poultry in moderation – avoid processed meats and ideally eat organic meat and poultry (where applicable)
  • Eat plenty of fish – fish is rich in Omega 3 essential fatty acids and to be encouraged at all stages of life; particularly oily fish (recommendations vary in pregnancy)
  • Avoid processed or refined foods and drinks
  • Avoid sugar and sugar rich foods (processed carbohydrates)
  • Encourage a diet high in the B-Complex vitamins
  • Encourage complex carbohydrates in your diet – ‘slow acting’ carbohydrates in moderation for fibre and energy are encouraged
  • If you are a vegetarian or vegan – ensure you are not deficient in important nutrients for mental and physical health that are typically found in meats and fish. These most commonly are Omega 3 (fish), Haem Iron (meat) and Vitamin B12 (meat). There are many suitable vegan alternative food sources and supplements available


Elevated levels of homocysteine in the blood is just one risk factor behind the onset of Alzheimer’s disease – and the majority of other chronic diseases. It is clearly important to add that there are many other contributing risk factors associated with the condition.

In this article we have indicated that elevated levels of homocysteine can be regulated back to normal levels if the correct guidelines are followed in terms of relevant supplementation, lifestyle choices and diet. If these guidelines are adopted by individuals in the presence of pertinent risk factors then we should see the number of Alzheimer’s sufferers reduce considerably in the coming decades.

In addition, the most recent research is excitingly suggesting that for those individuals even in the stages of early onset Alzheimer’s adopting the correct diet, lifestyle and nutrition protocols can help reverse the symptoms of the condition.

Indeed the most pertinent point to be taken from this blog, and one that we will be elaborating on in the coming months is that there is emerging evidence that Alzheimer’s is in fact a wholly preventable disease.

If you have any questions regarding this article, any of the health topics raised, or any other health matters please do get in touch by phone or email at any time.

Cytoplan Editorial Team, Cytoplan Ltd
amanda@cytoplan.co.uk, 01684 310099

 Relevant Products

To see the full range of our B vitamin supplements please follow the below link:

Vitamin B Supplements

Relevant Blogs

Alzheimer’s and Dementia – Time for ‘A Novel Therapeutic Programme’?

B-Vitamins & Alzheimer’s – The Debate Intensifies

Methylation: energy for life and living!

Vitamins for the Brain?

Can B-Vitamins Help Deter Alzheimer’s & Dementia?




Last updated on 22nd July 2015 by cytoffice


9 thoughts on “Elevated Homocysteine – A Risk Factor for Alzheimer’s Disease?

  1. I suffer from rheumatic arthritis can you suggest any health product to take to alleviate the disease?

    Thank you for your reply

    1. Hello Irene,

      I am so sorry to hear of your illness. There are a number of supplements and also foods that can help with this condition and the best outcomes are usually achieved from programmes based on your own individual needs. We have a Health Questionnaire available that I am sure would be of a great help to you (this is a free service) that looks at your dietary choices and lifestyle history, just so that we can try and determine the root cause of your problem. Please let me know if you would like me to send you one via e-mail or post.

      All the best,

  2. Excellent informative article. Helpful. I have rheumatoid arthritis and have a diet pretty similar,to one recommended in article. I also have fibromyalgia and take high dose magnesium and other supplements recommended b my Medical Herbalist. Since diagnosis of FM in 2002, I never dream, despite taking 20mg of time release melatonin every night. This leads me to wonder what happened to my brains once FM started and if I could be at risk of Alzheimers in the future? ?? (Something with which wold not want to live.) I am an active 67 despite aforementioned conditions.

    1. Hi Rosemary,

      Many thanks for your feedback. If you are sleeping well it is likely that you are dreaming but just not remembering your dreams. Melatonin does not make one remember dreams – but B Vitamins do help in this respect. I would suggest adding a B complex and in particular a good level of B12 which is the key B vitamin in this respect. Many people are short of B12 for many different reasons but my recommendation for you, all things considered would be – Super B Extra – 2 a day plus sublingual B12, 500ug, daily for 2 months.

      I would be more than happy to send you a free pot of Vitamin B12 and Super B Extra to get you started. So please let me know and e-mail me at amanda@cytoplan.co.uk.

      Best wishes


  3. Fascinating! I take B12 sublingual daily. It helps give me energy, helps me think more clearly and I just seem calmer. Now I understand better why! Thank you!

  4. I take multi B extra B12 sublingual and bone support. I would also like a form please as always wondered can you take too much it and would be nice to have some help thanks

  5. Thank you for this very informative blog, I do have a vitamin B12 deficiency and have injections every 3 months, it is obvious at times that waiting three months for everyone is unacceptable. Our doctors apparently have to follow the rules and treat everyone the same. We are not all the same. I have seen myself how Alzheimer’s effects people. It’s heart rending to watch. It is obviously impossible for B12 sufferers to change the law and allow the injection when needed. The government said no.
    Your artical out lines the importance of B12 in food. I would encourage this 100%. With hope that less people will suffer with Alzheimer’s. Beryl Laing

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