B Vitamins May Not Cut Heart Risks
In High-Risk Patients Taking B Vitamin Supplements, Heart Risks Remain
April 13, 2006 -- Supplements of three B vitamins -- folic acid, vitamin B-6, and vitamin B-12 -- don't appear to cut heart risks for high-risk patients.
That finding comes from two new studies, both published in The New England Journal of Medicine.
The studies' details differed, but their strategy was similar: Take a big group of people at high risk of heart problems, give some of them B vitamins and others no B vitamin supplements, and see what happens over the next few years.
In both studies, patients taking B vitamins had a drop in their blood level of homocysteine, an amino acid linked to heart disease. But lower homocysteine levels didn't cut deaths from heart attack, stroke, or other heart-related problems, the studies show.
HOPE 2 Study
The first study was the Heart Outcomes Prevention Evaluation (HOPE) 2 study. The HOPE 2 researchers included Eva Lonn, MD, of Hamilton General Hospital in Canada's Hamilton, Ontario.
Lonn and colleagues studied 5,522 patients aged 55 and older who had diabetes or vascular disease (disease that affects the blood vessels). The researchers randomly assigned patients to one of two daily treatments:
- Mix of 2.5 milligrams of folic acid, 50 milligrams of vitamin B, 1 milligram of vitamin B-12
- Sham pill containing no B vitamins (placebo)
Some patients lived in the U.S. and Canada, where enriched grain products are fortified with folic acid. Others lived in Brazil, western Europe, and Slovakia, where folic acid fortification isn't mandatory.
Over an average of five years, blood levels of homocysteine fell substantially in the vitamin group and rose in the placebo group. But both groups had a similar number of patients who died of heart attack, other heart problems, or stroke.
Those deaths included 519 patients in the vitamin group (nearly 19%) and 547 in the placebo group (nearly 20%).
The second study was the Norwegian Vitamin (NORVIT) trial. The researchers included Kaare Harald Bonaa, MD, PhD, of the University of Tromso in Tromso, Norway.
The NORVIT trial included 3,749 men and women who had had a heart attack up to a week before joining the study. The researchers randomly assigned patients to take one capsule per day containing one of four treatments:
- 0.8 milligrams of folic acid, 0.4 milligrams vitamin of B-12, 40 milligrams of vitamin B-6
- 0.8 milligrams of folic acid, 0.4 milligrams of vitamin B-12
- 40 milligrams of vitamin B-6
Over an average of three years, blood homocysteine levels fell 27%, on average, for patients given folic acid and vitamin B-12.
But none of the vitamin groups cut their risk of major cardiovascular "events," the researchers write. Those "events" were fatal or nonfatal heart attack, fatal or nonfatal stroke, and sudden death attributed to heart disease.