Vitamin industry and some researchers disagree that 'enough is enough' when it comes to supplement studies.
The latest studies on vitamins have some medical experts saying "case closed" — it's time for most consumers to stop wasting money on multivitamins and other supplements, because they have no proven benefits and some possible harms.
That declaration comes in a strongly worded editorial that accompanies two new studies and an expert panel's report published Monday in the Annals of Internal Medicine.
"The message is simple: Most supplements do not prevent chronic disease or death, their use is not justified, and they should be avoided," says the editorial, signed by two researchers from Johns Hopkins University in Baltimore, one British researcher and one of the journal's senior editors. After years of study and mostly disappointing results, the editorial says, "enough is enough."
"What we've found time and again is that the supplements are not working… we don't need to go on studying them forever," said editorial writer Eliseo Guallar of the Johns Hopkins Bloomberg School of Public Health, in a telephone interview.
Among those begging to differ are a vitamin industry group and one of the researchers whose studies prompted the editorial.
"While those in the ivory tower may say that people just need to eat their sardines and salads, in the real world there are nutrient gaps," says Duffy MacKay, of the Council for Responsible Nutrition, which represents supplement makers.
Research gaps remain too, says John Michael Gaziano, a researcher at Brigham and Women's Hospital and the VA Boston Healthcare System. He co-authored one of the new studies. "It drives me crazy that they say 'enough is enough,' when there's only been one large study of (standard) multivitamins and it's ours," he says.
The new results from that study will disappoint anyone who hoped a multivitamin might keep them sharp in old age. The study followed male physicians over age 65 for an average of 11 years and found multivitamins had no effect on cognitive decline. But previous results, published one year ago, suggested taking multivitamins led to an 8% decline in cancer risk in men over age 50. Additional results suggested multivitamins might lower the risk of cataracts.
Those findings of possible benefits are not definitive, but "I'd say the case is not closed," Gaziano says.
A second, unrelated, new study in Annals found high-dose multivitamins had no effect on the progression of heart disease in heart attack survivors. The journal also contains a previously released report from the U.S. Preventive Services Task Force. That report says "limited evidence supports any benefit from vitamin and mineral supplementation for the prevention of cancer or cardiovascular disease." It calls the possible effect on cancer in men "border-line significant." And it notes that some studies have found harm, particularly in the case of beta-carotene supplements, which increase lung cancer risks in smokers.
But studies have found no harm in standard multivitamins, and there's no evidence that taking vitamins causes people to eat worse or otherwise neglect their health, MacKay says.
One likely harm, Guallar says, is that most of the 53% of U.S. consumers who use supplements are wasting money, to the tune of $28 billion a year. He says research money is being wasted, too.
But he says there are exceptions. For example, health officials strongly urge women of childbearing age to take folic acid, to prevent birth defects. Some ongoing studies of vitamin D, he says, are justified because some benefits, such as preventing falls in the elderly, appear possible.
Ultimately, the decision about whether to take vitamins is personal. Physician Robert Wachter, an expert in patient safety at the University of California, San Francisco, says he agrees that most people who take supplements "are throwing money down the drain."
He also says he takes a daily multivitamin. That's because he is 56, comes from a family with a "huge amount of cancer," and finds the evidence of a possible protective effect for men like him compelling enough, he says.
But "there are other things that are of far greater benefit," he says, including not smoking, eating well and getting adequate exercise.