Homocysteine is an amino acid that is found normally in the body. If a person is relatively deficient in folic acid, vitamin B6, or vitamin B12, there will be an increase in the level of homocysteine. Recent studies suggest that high blood levels of this substance may increase a person's chances of developing heart disease, stroke, and reduced blood flow to the hands and feet. Homocysteine is thought to promote atherosclerosis by directly damaging the artery and by reducing the integrity of the vessel wall, by making the blood more likely to clot, as well as by interfering with the formation of Collagen (the main protein in bone).
Elevated homocysteine levels are an independent risk factor for heart attack, stroke, or peripheral vascular disease. Elevations in homocysteine are found in approximately twenty to forty percent of patients with heart disease. It is estimated that folic acid supplementation (400 meg daily) alone would reduce the number of heart attacks suffered by Americans each year by ten percent.
Individuals vary in their levels of homocysteine. For a few people, genetic factors contribute to high amounts of this substance in the blood. In addition, homocysteine levels may increase with age. For women, homocysteine levels may be higher after menopause than during childbearing years.
Recent research also shows that the level of homocysteine in the blood is affected by the consumption of three vitamins--folic acid, and vitamins B6 and B12. People who consume less than the recommended daily amounts of these vitamins are more likely to have higher homocysteine levels.
Recommended daily amounts are as follows: 400 micrograms for folic acid, 2
milligrams for B6, and 6 micrograms for B12.
How To Determine Your Homecysteine Level
Ask your doctor to order a blood test. If your homocysteine is low (6-8 micromoles per liter), you are at low risk of developing heart disease. If your homocysteine level is elevated (anything over 12 micromoles per liter), you can reduce it to a safe level by a modification in your diet.
The Homocysteine Theory of Dr. MacCulley
Dr. MacCulley, originally with Harvard University, is considered to be the father of Homocystein theory of heart disease. According to this theory, when there is too much homocysteine in the blood, arteries are damaged and plaques form. The result is arteriosclerosis and heart disease. This happens when we don't get enough of certain vitamins - namely B6, B12, and folic acid. These B vitamins are missing in our diets because the processing and refining of foods destroys these sensitive vitamins.
Besides diet, there are several other factors that can increase homocysteine in our blood. Some these are: genetic background, certain drugs, aging, hormonal changes such as menopause, smoking, physical activity, diabetes, and high blood pressure.
What you affects how your body prevents disease. An amino acid called methionine is one of the essential building blocks of all proteins in foods. It is abundant in meats and dairy products. In the body, methionine is normally converted to homocysteine. We need some methionine, but an excessive amount will create too much homocysteine, damaging the arteries.
Homocysteine can be converted back to methionine or excreted from the body by the three important B vitamins-folic acid, B6, and B12. So if meat eaters eat enough fruits and vegetables containing the proper B vitamins, homocysteine will not build up in the blood.
Vegetable proteins derived from grains, beans, peas, and other vegetables, on the other hand, contain less methionine than protein derived from meat, fish, and dairy products. So, less homocysteine is produced in the body when we eat vegetarian meals. Vegetarian diet has an additional benefit as far as the homocystein connection is concerned : they usually contain large amounts of B vitamins; so homocysteine levels are naturally kept low by these vitamins.
Thus, our diet greatly affects our propensity to develop heart disease. The way to prevent the disease is to improve the quality of your diet.
If you simply consume enough B6, B12, and folic acid from fresh whole foods, your homocysteine level will be kept low and you can avoid heart disease altogether, according to Dr. MacCulley.
Clinical Studies Proving That Elevated Homocystein Can Cause Heart Diseases
Large scale population studies definitively showed that elevation of blood homocysteine is associated with increased risk of heart attack and heart disease.
The Nurses' Health Study involving 80,000 participants in a fourteen-year period revealed that those nurses with the lowest consumption of folic acid and B6 had the highest death rates from cardiovascular disease and heart attack. (February 1998)
In a clinical study (April 1998) in England, 21,500 men were followed for almost nine years. Blood homocysteine levels were found to be higher in men who died of heart disease than in men who did not. The higher the blood homocysteine level, the higher the risk of dying from heart disease.
Physicians Health Study (1992) involving 14,000 participants showed that those with high homocysteine were three times more likely to have a heart attack during a five-year period than persons with normal levels.
5,000 people were studied in Canada for fourteen years as part of the Nutrition Canada Study. The results showed that those with the lowest levels of folic acid in the blood were almost twice as likely to die from heart disease as compared to those with the highest levels.
A study from Norway showed that among 587 patients with proven coronary heart disease, risk of death is directly related to the level of homocysteine in the blood.
A study of 16,000 residents of Norway showed that homocysteine increases in the presence of other known risk factors for heart disease such as male gender, old age, smoking, high blood pressure, elevated cholesterol level, and lack of exercise.
A multi-country study in 1997 showed that the death rate from coronary heart disease is directly related to blood homocysteine levels.
All these studies support the validity of the homocysteine theory of heart disease.
Vitamin Therapy May Be Useful In Preventing Heart Disease
Vitamin therapy can be used to lower the homocysteine levels. This may lower the risk of heart disease. If you already have heart disease, vitamin therapy can lower homocysteine and stop the disease from progressing.
Several clinical studies showed that B vitamin therapy can prevent arteriosclerosis from getting worse.
In a 1998 clinical study done in Canada, patients with elevated homocysteine and arteriosclerosis of arteries to the brain were given intensive therapy with folic acid, vitamin B6, and vitamin B12. As a result of the therapy, the plaques stopped progressing and the homocysteine levels returned to normal.
In a 1996 study of patients with coronary heart disease, vitamin therapy (vitamin B6, folic acid, B12, and other nutrients) slowed the development of the disease.
Dr. McCulley recommends 400 micrograms of folic acid, 2-3 milligrams of Vitamin B6, and 6 micrograms of Vitamin B12. This can be provided by supplementation or by diet.
Good sources of folic acid include citrus fruits, tomatoes, vegetables, whole and fortified-grain products, beans and lentils.
Foods high in B6 include meat, poultry, fish, fruits, vegetables and grain products. Major sources of B12 are meat, poultry, fish, and milk and other dairy products.
© 2005 HealthSmart Nutrition. All rights reserved.
Revised: February 01, 2006