Homocysteine – more important than cholesterol?

Dr Paul Clayton 2006

Several years ago the first edition of Health Defence reported on the importance of homocysteine as probably a more important marker for heart disease than LDL cholesterol. Since then it is exciting a flurry of medical research, with over 8,000 papers published on the subject during 2004 alone. Research has shown that people with high homocysteine levels have a 3 times higher risk than those with a normal levels, and it is also now seen as a marker for stroke, osteoporosis, dementia and birth defects.

Homocysteine is an amino acid that is naturally made in the body during the breakdown of another amino acid, methionine. Usually, homocysteine is quickly converted by certain enzymes into other harmless substances, but these enzymes need good supplies of vitamins B12, B6 and folic acid to work properly.

Some people inherit versions of the enzymes that work poorly, or which need higher levels of vitamins to function properly. Homocysteine processing also becomes less efficient as we get older, especially after the menopause in women. As a result, an estimated 15% of the population (and almost 30% of those with coronary heart disease) do not break down homocysteine properly. One in 160,000 people have high enough levels of homocysteine to increase their risk of premature heart disease by thirty times!

Homocysteine triggers oxidation of LDL cholesterol so it is more likely to stick to artery walls, forming atheroma. It also seems to encourage excess growth of smooth muscle cells in the artery linings and interferes with the normal dilation and contraction of blood walls and hastens the development of abnormal blood clots(1).

What is a normal level?

We know that many NutriShield clients do have annual or bi-annual check-ups, so it is important to know what levels to look for. The safe, normal level of homocysteine is still not ascertained, but the indications are that levels over 9.9 micromol/L may be harmful for longterm health. As homocysteine levels naturally rise with age, however, a level of 12 or under could be acceptable for those aged over 60.

Homocysteine mmol/L Risk

up to 6.9 Low (optimum)
7.0 – 9.9 Mild
10.0 – 12.9 Moderate
13.0 – 19.9 High
20.0 and over Very High

A diet to lower homocysteine

To process homocysteine, it is important to eat plenty of foods that are rich in folate and vitamins B12 and B6. Unfortunately, dietary lack of these vitamins seems to be common. A survey in the US suggests that only 40 – 50% of people obtained enough folic acid from their diet to process homocysteine normally. And Harvard Medical School recently warned in its Health Letter that vitamin B12 deficiency is the most common nutritional deficiency in the Western world. Adults over 50 are also more likely to be deficient, as a third of people in this age-group suffer from atrophic gastritis, where the stomach lining thins and the amount of B12 absorbed by the small intestine is reduced.

Folate (the natural form of folic acid) is found in green leafy vegetables, whole grains, nuts, beans and yeast extracts. Vitamins B12 and B6 are in liver, kidney, oily fish especially sardines, red meats and eggs. Some B6 is also present in whole grains, soy products, bananas, nuts (especially walnuts), green leaves, avocado and yeast extract.

It is hard to obtain optimum levels from foods alone. Natural folate, for example, is not absorbed or used in the body as well as the synthetic form, folic acid, so supplements and fortified foods are usually needed as well to have a significant effect on homocysteine levels.

In addition to folic acid, B12 and B6, several studies(2) have shown that betaine is highly effective in helping to lower homocysteine levels. It is particularly important in the many people who are unable to metabolise folic acid effectively. And these should all be combined with antioxidant compounds and co-factors such as selenium, vitamins A C and E, the carotenoids and the flavonoids – all of which are in NutriShield.


Guthikonda S, Haynes WG. Homocysteine: role and implications in atherosclerosis. Curr Atheroscler Rep 2006 Mar;8(2):100-6. Review.

Schwab U et al. Orally administered betaine … J Nutr 2006 Jan;136(1):34-8.