Alas, poor Yorick. Would he have lived longer if he and Hamlet had upped their doses of B vitamins?
They might have if their downfalls were cardiovascular. Though studies released throughout the past couple years have caused some to question the precise roles B vitamins play in maintaining heart health, most agree that "the Bs" are important in preventing heart disease.
"I'd stake some money on it, that if two groups of patients were studied—one group given a comprehensive multivitamin with the Bs and one given a comprehensive multivitamin without the Bs—there would be a significant reduction [of cardiac risk] for those who took the vitamins with the Bs," says Dr. Alan Gaby, author of the classic B6: The Natural Healer (Keats, 1987), former endowed professor of nutrition at Bastyr University and past president of the American Holistic Medical Association.
There are eight B-complex vitamins: B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B9 (folic acid), B12 (cyanocobalamine) and biotin.
"The main physiologic function of B vitamins is to assist the body in the metabolism of macronutrients [protein, carbohydrates and fat] for energy," explains Dr. Andrew Shao, vice president of scientific and regulatory affairs for the Council for Responsible Nutrition. Other functions include helping nerves and neurons work properly, DNA synthesis and repair and, in some cases, management of blood lipid levels, including cholesterol.
Four B vitamins that have been extensively studied for their relation to heart health are B6, B12, niacin and folate (folic acid is the synthetic form of folate found in supplements and added to food). A wide variety of foods are rich in B vitamins, but a good deal of people rely on supplements to get their recommended daily allowances. About 35 percent of Americans take B vitamins, mostly in the form of multivitamin pills, according to the Council for Responsible Nutrition.
The homocysteine hypothesis
Two studies published in The New England Journal of Medicine (2006) and one published in Journal of the American Medical Association (2004), blasted a widely held hypothesis that B vitamins could protect against homocysteine and, therefore, heart disease. Homocysteine is an amino acid that some experts believed was as important a risk factor for heart disease as cholesterol. Because B vitamins are known to lower homocysteine levels, it was believed that taking them would also prevent heart disease by lowering cholesterol levels.
But, according to these studies, that didn't happen.
Altogether, in the three studies, 9,000 patients who were at high risk of a heart attack or stroke were given supplemental B vitamins, or placebos, and studied for several years. While their homocysteine levels dropped by almost a third, the patients who had taken the Bs had about the same number of heart attacks and strokes as those who took the placebos. It seems homocysteine is a symptom, or marker, of heart disease, not a cause.
No proof ? yet
The results of these studies—and the media attention they garnered—could be misleading, many argue. The studies examined people who had already had a heart attack or stroke, and while the results showed that the B vitamins didn't lower their risk of a second cardiac event, the studies did not look at how B vitamin supplementation might effect a healthier population, says Annette Dickinson, Ph.D., former president of CRN. "The studies didn't answer the question about whether B vitamins help prevent heart disease in the first place," she says. "In addition, there is some debate about whether adequate amounts of the vitamins, particularly B12, were used in the studies."
Gaby questions the studies from a medical nutritionist's perspective. "The studies were done monolithically, like drug studies," he says, "and that's not the way nutrition works." The patients in the studies were given high doses of single nutrients, as opposed to a broad-spectrum multivitamin/multimineral preparation and a nutrient-dense diet. Nutrients work as a team, and the benefits of single nutrients may not be evident if a person is deficient in other essential nutrients, he explains.
"It will take a long time, but I believe research will prove [that the Bs lower the risk of heart disease]," he says.
"The bottom line," Dickinson says, "is that various kinds of evidence suggests that benefits should exist. There are studies under way, including one with a higher level of B12. Many researchers believe the hypothesis will be proven. It's good to have a generous intake [of the Bs], but exactly what that level should be for healthy people is what researchers are now focused on."
In the meantime, "a wealth of observational studies suggest that high intake of B vitamins is associated with a lower risk of heart disease—starting with a healthy population," Shao says.
No doubt about niacin
There is no debate surrounding niacin's role in heart health. "It's a known cholesterol-lowering agent," Dickinson says. The levels required to lower cholesterol are quite high, and such doses should only be taken under strict medical supervision, as niacin can strain the liver. Flushing, where a person's face gets red, is another, less serious, possible side effect of taking high doses of niacin.
Taking more than 200 milligrams of B6 a day can cause nerve damage, Gaby notes. In general, safe and effective daily doses of the Bs are as follows, according to Shao: folic acid, 400 micrograms; B12, 10 to 50 micrograms; B6, 6 milligrams; niacin, 25 to 50 milligrams.
"In general, the B vitamins are among the safest of all vitamins," Shao says. "The lack of toxicity with these has led the [Institute of Medicine] to not set upper limits."
So, "Good night, sweet prince." Don't forget to take your B vitamins.
Shara Rutberg is a Boulder, Colo.-based freelance writer.
Natural Foods Merchandiser volume XXVIII/number 12/p. 45