The study shows that coronary artery disease patients taking cardiovascular drugs didn't cut their risk of death, nonfatal heart attack or clot-related stroke, or other problems by taking folic acid, vitamin B12, and/or vitamin B6 supplements for about three years.
This isn't the first study to come to that conclusion, and even the Council for Responsible Nutrition, a trade group for the dietary supplement industry, doesn't question the latest findings. But the council argues that the results may not apply to people with healthy hearts.
Heart Disease and B Vitamins
The new study included more than 3,000 heart disease patients in Norway, where folic acid isn't added to wheat as it is in the U.S.
When the study started, the patients were in their early 60s, on average. More than 75% were taking statins, anti-platelet drugs, and beta-blockers to treat their heart disease.
The patients kept taking those drugs during the study. They were also randomly assigned to either take folic acid plus vitamins B6 and B12, folic acid plus vitamin B12, vitamin B6 alone, or a placebo pill -- without knowing which group they were in.
During the study, which lasted for just over three years, the patients got periodic blood tests to measure their level of homocysteine, which is an inflammatory chemical linked to higher rates of heart disease.
The researchers expected homocysteine levels to drop in the folic acid groups. The key question was what difference that would make to the patients' heart health. The short answer: Homocysteine levels fell as predicted, but it didn't matter much.
No Support for B Vitamins
Over the course of the trial, the patients taking folic acid and vitamin B12 had the biggest drop in their homocysteine level, which wound up 26% lower than patients who weren't taking folic acid.
But even those patients weren't less likely to die of any cause, suffer a nonfatal heart attack or clot-related stroke, be hospitalized due to unstable angina (chest pain), or need to have a narrowed or blocked coronary artery surgically reopened.
Those "events" happened to similar percentages of patients -- ranging from 12% to 16% -- in each group. The differences in those percentages were so small that they may have been due to chance.
"Our findings do not support the use of B vitamins as secondary prevention in patients with coronary artery disease," write the researchers, who included Marta Ebbing, MD, of Norway's Haukeland University Hospital.