The PHS II study is the same one that recently found that a daily multivitamin may reduce the risk of cancer by 8%.
The researchers concluded: “These data do not support multivitamin use to prevent CVD, demonstrating the importance of long-term clinical trials of commonly used nutritional supplements.
“Whether to take a daily multivitamin requires consideration of an individual’s nutritional status, because the aim of supplementation is to prevent vitamin and mineral deficiency, plus consideration of other potential effects, including a modest reduction in cancer and other important outcomes in PHS II that will be reported separately.”
Speaking to NutraIngredients-USA, Duffy MacKay, ND, vice president, scientific and regulatory affairs for the Council for Responsible Nutrition (CRN), said it was a valuable and rigorous study. “We’re pleased about that,” he said.
There was no surprise with the results, he said. “Did I expect a multivitamin to have a major impact on cardiovascular events? Not specifically in this population – an extremely healthy population.”
The authors themselves admitted: “Several behavioral (eg, exercise, weight loss) and pharmacological (eg, lipid-lowering therapies) interventions are available to effectively lower CVD risk. This may make it difficult for vitamin supplements such as a multivitamin to meaningfully contribute toward risk reduction.”
This, said Dr MacKay, is a really important point. “These are not typical Americans.”
“These physicians are doing everything right to prevent heart disease. Their diets were healthy, their BMIs were low, they exercised, very few smoked, and the majority was on a daily aspirin regimen.
“The floor in this population may have been too close to the ceiling for a simple multivitamin to have demonstrated additional benefit for preventing strokes and heart attacks.”
Dr MacKay also said that the results don’t discount the many other benefits that multivitamins provide, including filling nutrient gaps, helping prevent neural tube birth defects, and serving in combination with other healthy habits as a basic and affordable insurance policy for overall wellness.
“Even though two weeks ago, this same study demonstrated a modest but significant reduction in total cancer risk in this same population, no one should expect the multivitamin to wipe out all diseases known to man.”
Other ingredients, other benefits
Commenting on the multivitamin formulation, Dr MacKay added that the supplements did not include many of the ‘bigger’ ingredients with purported heart health benefits, like plant sterols, soluble fiber, CoQ10, and omega-3.
“We need to ensure that these results are not over generalized into ‘dietary supplements don’t help for heart health’,” he said.
Led by Howard Sesso, ScD, of Brigham and Women's Hospital and Harvard Medical School, Boston, the researchers analyzed data from 14,641 male US physicians participating in the Physicians’ Health Study (PHS) II. PHS II is the only large-scale, randomized, double-blind, placebo-controlled trial investigating the long-term effects of a common multivitamin in the prevention of chronic disease.
The men were randomly assigned to receive a daily multivitamin or equivalent placebo for more than 10 years of intervention and follow-up. No significant reductions were observed for major cardiovascular events, heart attack, stroke, or death from cardiovascular disease, said the researchers.
The researchers did report that there were fewer total deaths among multivitamin users, but this difference was not statistically significant.
Additional analysis also revealed that a the small number of multivitamin users who had cardiovascular disease at the start of the study were significantly less likely to die of a heart attack (44% risk reduction).
Healthy practices, unhealthy lifestyles?
In an accompanying editorial, Eva Lonn, MD, from McMaster University in Canada, said: “Nonetheless, many people with heart disease risk factors or previous CVD events lead sedentary lifestyles, eat processed or fast foods, continue to smoke, and stop taking lifesaving prescribed medications, but purchase and regularly use vitamins and other dietary supplements, in the hope that this approach will prevent a future myocardial infarction or stroke.
“This distraction from effective CVD prevention is the main hazard of using vitamins and other unproven supplements.”
However, CRN’s Dr MacKay disagreed with such statements. “It’s unfortunate that the accompanying editorial makes negative assumptions about the habits of vitamin users, when the research demonstrates supplement users are taking them in combination with other healthy lifestyle choices,” he said.
“Government and other studies show that supplement users are more likely to be leaner and more physically active than non-supplement users [see references below]. Our own research shows similar kinds of results, with supplement users being more likely than non-users to try to eat a healthy diet, engage in regular physical activity, and see a doctor regularly.
“It’s the whole lifestyle package, including consistent, long-term use of vitamins, that helps lead to good health.”
The study was supported by the National Institutes of Health and an investigator-initiated grant from BASF Corporation. The multivitamins used in the study were provided by BASF Corporation and Pfizer, and study packaging was provided by DSM Nutritional Products.
2012, Volume 308, Number 17, Pages 1751-1760
“Multivitamins in the Prevention of Cardiovascular Disease in Men The Physicians’ Health Study II Randomized Controlled Trial”
Authors: H.D. Sesso, W.G. Christen, V. Bubes, J.P. Smith, J. MacFadyen, M. Schvartz, J.E. Manson, R.J. Glynn, J.E. Buring, J.M. Gaziano
2012, Volume 308, Number 17, Pages 1802-1803
“Multivitamins in Prevention of Cardiovascular Disease”
Author: E.M. Lonn