high homocysteine

The Hidden Heart Disease Risk Factor: High Homocysteine

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You may unknowingly have a ticking time bomb for heart disease flowing through your body. Right now. And you haven’t been told about it. Until now. Naturally produced in your body, a chemical substance called homocysteine often becomes elevated due to age, diet, and genetic disposition. If your homocysteine is high, you are at an increased risk of developing heart disease including heart attacks, coronary artery diseases, and strokes.

Staggering Mortality Rates

Heart disease is the number one cause of death worldwide. More than 17 million people—nine million of whom are women–die annually from heart disease.

In the United States heart disease ranks as the top killer of women. More than 500 American females die daily from heart disease. Furthermore, heart disease deaths in American women under the age of 55 continue to rise, according to a study published in the June 2013 issue of the journal Global Heart.

Why are so many people dying from heart disease? We have been educated to believe high blood pressure, high LDL cholesterol, and smoking are the primary causal culprits in causing heart disease. Physical inactivity, obesity, and excessive alcohol use also are attributed as risk factors for heart disease. But we hear little information about homocysteine as an independent factor for heart disease.

What is Homocysteine?

Homocysteine is an amino acid (a building block of protein) naturally produced in the body from a byproduct of another amino acid called methionine. Healthy amounts of homocysteine are vital in protein metabolism. However, homocysteine levels must be carefully balanced by adequate quantities of specific B vitamins.

Ideally, about half of homocysteine is recycled back into methionine (remethylation), and the other half is converted into a beneficial amino acid called cysteine (transsulfuration). This bifurcated process is dependent on specific B vitamins. Remethylation cannot occur without folate (vitamin B9) and vitamin B12. Transsulfuration cannot happen without vitamin B6. If these B vitamins are deficient, dangerous levels of homocysteine can accumulate in the body and damage the lining of the arteries, often causing heart disease.

Homocysteine Matters

In the late 1960s, Kilmer S. McCully, M.D., a young pathologist at Harvard University School of Medicine, reviewed a number of pathological findings of cases as far back as 1933 that involved young children with a genetic disorder who perished from atherosclerosis (hardening of the arteries). He discovered that elevated homocysteine damages arterial lining, causing arterosclerosis. Dr. McCully concluded that elevated homocysteine from a high animal-protein diet, more so than fats and cholesterol, was the primary cause of heart disease.

McCully subsequently published his ground-breaking conclusion in a 1969 issue of the American Journal of Pathology. By purporting such an unorthodox theory, he committed medical heresy.(1) Harvard denied him tenure, effectively firing him. Undeterred, he forged ahead, conducting research on homocysteine. He still practices medicine in the United States today.

Thanks to Dr. McCully’s tenacious efforts over the past four decades, a plethora of studies supporting his theory have been published. Landmark studies from the mid-1990s contributed to mainstream medicine’s eventual, yet delicate, embrace of the fact that high homocysteine is significant risk factor for heart disease. This research includes:

As part of the acclaimed Framingham Heart Study, researchers from Tufts University examined 418 men and 623 women, ages 67 to 96 years, to study their homocysteine blood plasma levels as well as their vitamin intake including folate, vitamin B12, and vitamin B6. The Tuft research team concluded that people with homocysteine levels greater than 11.4 µmol/L have a significant risk of having a heart attack. These findings were published in the February 2, 1995 edition of the New England Journal of Medicine.

The results of a study conducted by The European Concerted Action Project, a consortium of doctors and researchers from 19 medical centers in nine European countries, clinched the theory that Dr. McCully asserted almost two decades prior. By comparing 750 people under the age of 60 with blockages in their coronary arteries with 800 healthy persons also under 60 years old, the Project team determined that an elevated homocysteine score posed as great a risk as smoking or high cholesterol. Furthermore, people with the highest homocysteine levels had twice the risk of developing heart disease. Finally, the consortium discovered that those people who took folate, B12, and B6 supplements had a risk factor of about 66 percent less than those subjects who did not take the B vitamin supplements. The findings were published in the June 11, 1997 issue of the Journal of the American Medical Association.

What is a Healthy Homocysteine Level?

Homocysteine levels are easily evaluated by a simple test of blood plasma. Heath care practitioners can order a homocysteine test. But guess what? We are not routinely tested for homocysteine. In fact, I never had been tested for this important amino acid until I recently requested the test from my primary care physician. (Read on for my homocysteine score.)

To further exacerbate the issue of homocysteine evaluation, many clinical testing laboratories consider a healthy homocysteine value between 5 and up to 15 µmol/L. However, the upper limit of this range is highly misleading. A score of 6 µmol/L or less is optimal for homocysteine. Medical research has indicated that readings greater than 9 µmol/L indicate an increased risk for heart disease.

Reducing Homocysteine

The good news is that elevated homocysteine levels can be decreased by consuming adequate amounts of the B vitamins folate, B12, and B6. Although the daily dosage of these vitamins is dependent upon your homocysteine score, I offer general guidelines.

  • Foods rich in folate include wheat germ, lentils, sunflower seeds, spinach, broccoli, and romaine lettuce. If you are considering a supplement, note that “folate” is natural and “folic acid” is synthetic. Consider taking a daily 400-mcg folate capsule containing L-5-MTHF. (2)
  • The best food sources of vitamin B12 include sardines, oysters, cottage cheese, and tuna. When supplementing with B12, please ensure the B12 is methylcobalamin (methylB12). Many B12 supplements contain cyanocobalamin; yes, it contains a cyanide molecule. Consider taking 10,000 mcg daily of methylB12.
  • Fish and lean meats are excellent sources of vitamin B6 (pyridoxine). Consider taking a 25-mg B6 supplement.

You may recall that the amino acid methionine produces homocysteine. Too much methionine translates to excessive homocysteine. As animal protein is highly rich in methionine, it is wise to not overload animal protein consumption if the three major B vitamins are deficient.

Stunning Health Statistics

The scope of this article is limited to a brief discussion of elevated homocysteine as an independent risk factor for heart disease. However, I must tell you that homocysteine levels also affect the risk for developing a wide range of other serious medical conditions including cancer, diabetes, thyroid disorders, and Alzheimer’s disease. Let’s take a broad look at statistics.

Nestled in the spectacular western fjords of Norway, the University of Bergen houses one of the world’s leading homocysteine research centers. Since the 1990s, Bergen’s researchers have published dozens of papers reporting their homocysteine findings conducted during the University’s population-based Hordaland Homocysteine Study.

Having measured the homocysteine levels of 4,766 Norwegian men and women in their 60s a decade ago and then recorded those who lived and died, the researchers discovered that a 5-point decrease in homocysteine scores predicted, inter alia, a 50 percent reduced risk of death from cardiovascular disease as well as a 104 percent decreased risk of mortality from any disease or medical condition other than heart disease or cancer!

Are You Homocysteine Healthy?

It is not too early or too late to learn your homocysteine score. At the age of 60 and with a family history of heart disease, I requested a baseline homocysteine blood plasma test from my doctor. My score was an optimal 6µmol/L, a value that is most common in preteens! I attribute my homocysteine health score to feeding my body the folate, B12, and B6 it needs to maintain a balanced level of homocysteine.

Your level will not only predict your risk for heart and other serious diseases but it will help you understand how you can add energy and vitality to your life. Based on your homocysteine score, you can supplement with the necessary foods and/or dietary supplements that are readily available in retail and online outlets. And enjoy the benefits of being homocysteine healthy! I am glad than I am.

Footnote 1: Natural vitamins cannot be patented. Therefore, manufacturing and selling vitamins is far less lucrative than, for example, statins (cholesterol-lowing drugs.)

Footnote 2: The enzyme MTHFR (methylenetetrahydrofolate reductase) helps to facilitate the conversion process of remethylation.

Author’s Note: I wrote this overview to promote awareness of the potential heart disease risks associated with high homocysteine plasma levels. I briefly touched on the adverse effect of elevated homocysteine on the development of other serious medical conditions. If you are interested in learning more about homocysteine, I suggest reading: The H Factor Solution by James Braly, M.D. and Patrick Holford and/or The Homocysteine Revolution by Kilmer McCully, M.D.

Editor’s Note: Susan Rex Ryan is the author of the Mom’s Choice Award®-winning book Defend Your Life about the extensive health benefits of vitamin D. For additional information about vitamin D, check out our series of Sue’s articles, and visit her blog at smilinsuepubs.com.

This article was published previously on Hormones Matter in June 2014.

Copyright © 2014 by Susan Rex Ryan. All rights reserved.

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Susan Rex Ryan is the author of the award-winning book “Defend Your Life” about the amazing health benefits of vitamin D. Drop by Sue's website and blog at http://smilinsuepubs.com. Follow Sue’s commentary on vitamin D and other health topics via X @VitD3Sue. Like Sue's Defend Your Life page on Facebook


  1. True. Heart Disease can be minimized by eating foods containing vitamin B3 including: fish, and turkey, beef, nuts, sunflower seeds, mushrooms, avocados, broccoli

    thanks for the information

  2. Heart disease is very dangerous. Already many cases of sudden death caused by heart disease. Therefore we must be smart to maintain health to avoid heart disease. thank you

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