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The August 20, 2008, issue of The Journal of the American Medical Association (JAMA) contained a paper entitled “Mortality and Cardiovascular Events in Patients Treated with Homocysteine-Lowering B Vitamins After Coronary Angiography.” Many news outlets have featured this study in headline stories. In Canada, The Globe and Mail addressed the findings in “B vitamins: no magic bullet against heart disease” published in its August 20 edition.
The following information has been prepared by Jamieson Laboratories to offer a science-based summary and interpretation of the study’s key findings and to address inaccurate conclusions in the media, including those in The Globe and Mail.
What was the objective of this study?
The JAMA study was designed to explore some basic tenets of cardiovascular disease. Through observational and experimental studies, it has already been established that elevated homocysteine levels are associated with an increased risk of cardiovascular disease. It is also known that folic acid, vitamin B6 and vitamin B12 reduce homocysteine levels in blood.
The JAMA researchers described their investigation as a “secondary prevention study” of patients with existing cardiovascular disease. Their goal was to test the hypothesis: Could long-term treatment with folic acid and vitamins B12 or B6, alone or in combination, lower the incidence of myocardial infarction (heart attack) and stroke in this group?
The study hypothesis, though interesting, is a leap in logic.
One question surrounding homocysteine concerns whether this amino acid is a marker (an indicator) of heart disease or a cause of it. The answer is currently being sought in numerous research labs around the world. Without it, there is currently no direct deductive association between vitamin B supplementation and heart attack specifically.
What impact should this study have on my use of B vitamins?
Absolutely none. This study has an extremely narrow scope. It was testing the potential for certain B vitamins to protect existing heart patients from future heart events. The fact that this hypothesis was not affirmed within this single study says nothing about the primary preventive benefits of B vitamins or their myriad other health benefits.
In its interpretation of the study, The Globe and Mail article opens with the observation that “if you are taking vitamin B supplements to guard against heart disease you are wasting your money.” This statement is false. There is still a clear link between B vitamins and heart health as part of an overall health strategy.
Millions of people around the world take B vitamin supplements in complex combination formulas — typically on the advice of their doctor. In addition to reducing homocysteine levels, vitamin B reduces stress (a contributing factor in heart disease), increases energy production, improves nerve, liver, muscle and brain function and enhances skin health. These benefits are heightened for the elderly and people on carbohydrate-reduced diets.
Vitamin B is also known to prevent spina bifida and colon cancer. In Canada and the United States, studies have shown that deaths from stroke have been reduced by 10 to 15 percent lower since folic acid was added to wheat. Around the world, nearly 50,000 participants are involved in 11 other major medical studies designed to illuminate the benefits of B vitamins and help determine whether folic acid should be preventatively added to wheat in developing countries.
None of these benefits was challenged by this study.
Who participated in the study?
More than 3,000 volunteers participated in the study. All participants were cardiovascular-disease patients undergoing intensive conventional treatment. While all test participants were screened for other life-threatening diseases, the study does not indicate their status regarding known risk factors for future heart disease, such as smoking, high blood cholesterol, high blood pressure, physical inactivity, obesity and diabetes. Any of these factors alone could have a significant impact on the results.
How was the study designed?
The high-risk participants, all of whom had diagnosed coronary artery disease, were divided into four groups. In addition to standard heart medicines, they were each given a daily test regimen. One group took vitamins B6 and B12 and folic acid. Another group took folic acid and B12. A third group took B6 only. The fourth group was given a placebo. The study, which was originally designed with a four-year follow-up, was terminated after 38 months.
What were the reported findings?
The study confirmed previous knowledge that certain B vitamin supplements dramatically lower homocysteine levels. The researchers also identified a slightly lower risk of stroke among vitamin B users.
They added, however, that the study did not show “any preventive effect of intervention with folic acid plus vitamin B12 or with vitamin B6 on mortality or major cardiovascular events among patients with mainly stable CAD undergoing intensive conventional treatment.” In other words when it came to new heart attacks, there was no perceived difference in the outcomes for participants whether they were taking placebos, B vitamins or folic acid.
Are the conclusions valid?
At best, the researchers’ conclusions are open to debate. The American Heart Association (AHA) recognizes that reducing homocysteine levels in the blood may be preventive in elevated-risk patients with a personal or family history of cardiovascular disease if they have no other complicating factors or conditions. This recommendation relates to the science of the day: no laboratory has yet answered the question whether homocysteine is an indicator or a cause of heart disease. We only know that it is associated with an increased risk of heart disease.
The AHA also recommends that physicians advise high-risk patients to include sufficient amounts of folic acid and vitamins B6 and B12 in their diets.
Is the study flawed?
Yes. The study has been called “inconclusive” because of its complex two-by two factorial design. In this kind of analysis, the researchers examined the effect of two or more independent variables relating to heart disease, each one by itself and also in interaction with the others.
According to some experts, this approach does not sufficiently isolate any one of the variables so as to absolutely and firmly conclude that vitamin B therapy caused a benefit or harm.
The most glaring concern relates to the study featuring only very high-risk patients. No one yet knows whether the conventional wisdom on vitamin B therapy applies to patients who have already suffered a heart attack or have other complicating cardiovascular risk factors.
Could B vitamins have a negative effect on my health?
Absolutely not. Nothing in the study suggests that B vitamins are harmful to overall health or that they increase the risk of a heart event. Furthermore, no test parameters were established to correlate specific health outcomes with a specific type of B vitamin at a specific dose.
Why is this study attracting so much attention?
Heart disease is the number-one killer of North American men and women. Several unanswered questions remain about its prevention, onset and progression. Research that deals with heart disease will always garner headlines — rightfully so.
Ultimately, the best way to fight heart disease is through a healthy active lifestyle — balanced diet, physical activity, weight management, stress reduction, sleep and the use of quality nutritional supplements — and sound medical advice regarding your family history.
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