Additional Information On The Relationship Between Homocysteine Levels, B-Vitamins, and Coronary Heart Disease
Homocysteine, a byproduct of protein metabolism, became the focus of heart disease research just a few years ago, after researchers became convinced of its importance as a predictor of heart disease risk. Indeed, many experts believe high blood levels of homocysteine may rival high blood cholesterol levels in predicting heart attacks and strokes (see Environmental Nutrition, January 1994 and March 1995). It is thought that homocysteine may make the lining of arteries more susceptible to damage by increasing the stickiness of blood platelets.
Now, researchers at the Cleveland Clinic have confirmed that homocysteine is just as important a risk factor for women and older individuals as it is for middle-aged men. In a study of 304 men and women with heart disease, a stunning 58% of those over 65 years of age and 42% of those under 65 had what the researchers considered risky homocysteine levels.
Moreover, blood levels previously considered to be normal may carry some increased risk, according to lead researcher and cardiologist Killian Robinson, M.D. In the study, each five-point increase in homocysteine doubled heart disease risk.
Yet another group of researchers, from Haukeland University Hospital in Bergen, Norway, recently reported a strong correlation between homocysteine and other risk factors for heart disease in over 16,000 healthy men and women aged 40 to 67. High levels of homocysteine were most likely in those who were male, older, cigarette smokers or had high blood pressure, elevated cholesterol or did not exercise.
Moreover, the Norwegian researchers think the homocysteine association is not coincidental or simply a marker, but that homocysteine may actually cause some of the problems. The known benefits of exercise on heart disease risk, for example, might be explained by the fact that as physical activity increases, homocysteine levels decrease. And perhaps an increase in homocysteine is one of the reasons why cigarette smoking is such risky behavior for the heart.
B Vitamins to the Rescue.
Is there a way to lower homocysteine levels? There may be. The B vitamins, B6, B12 and folic acid, help clear the blood of homocysteine. Previous studies have found that low blood levels of B6 and folic acid correspond to high homocysteine blood levels and vice versa.
Moreover, in the Norway study both vitamin supplement use and intake of fruits and vegetables were closely linked to lower homocysteine levels. The Cleveland Clinic's Robinson suggests that elevated homocysteine levels are a signal that B6, folic acid and B12 status may be suboptimal, though not necessarily enough to trigger recognizable deficiency symptoms.
Though Robinson points out there's no direct evidence that taking specific supplements of B vitamins will lower blood homocysteine levels and therefore heart disease risk, it's certainly not jumping the gun to ensure you get enough of these vitamins in your diet.
That's especially important for vitamin B6, suggests the Cleveland Clinic study. It revealed that a B6 deficiency is a risk factor by itself, independent of homocysteine. Ten percent of those studied were deficient in B6, which quadrupled heart disease risk.
B6-rich foods include bananas, broccoli, chicken, dried beans, lean pork, peanut butter, potatoes, tuna and whole wheat bread. Folic acid-rich choices feature orange juice (particularly high), as well as beets, broccoli. dried beans, peas, spinach and wheat germ. Alternatively, a multivitamin supplement at 100% U.S. Recommended Daily Allowance levels is probably adequate to prevent a borderline deficiency of either vitamin.