"Enough is enough: stop wasting money on vitamin and mineral supplements," say medical experts in an editorial of a leading journal that has just published three new studies examining whether routine use of vitamin and mineral supplements brings health benefits.
Writing in Annals of Internal Medicine, the editorial authors conclude that most supplements do not prevent chronic disease or death, some may even be harmful in well-nourished adults, and there is a large body of evidence to support this.
Their routine use is not justified and they should be avoided, they urge, noting that:
"This message is especially true for the general population with no clear evidence of micronutrient deficiencies, who represent most supplement users in the United States and in other countries."
Editorial co-author Dr. Edgar Miller, professor of medicine and epidemiology at Johns Hopkins Bloomberg School of Public Health in Baltimore, MD, told CBS News that people would be better off spending money on healthy foods, such as "fruits, vegetables, nuts, beans, low-fat dairy," and getting exercise.
US consumers spend over $28 billion a year on supplements
In the editorial, Dr. Miller and colleagues say despite "sobering evidence" of no health benefit and even of possible harm, US adults are spending more and more on multivitamins.
They note how use of multivitamins increased among US adults from 30% between 1988 and 1994 to 39% between 2003 and 2006, while overall use of dietary supplements grew from 42% to 53% over the same period.
There have been some dips - for instance, studies have linked certain supplements to negative outcomes - but overall the supplements industry has kept growing. In the US, it reached $28 billion a year in 2010. Trends in the UK and other European countries are similar, notes the editorial.
One point that stands out in the editorial is that consumers seem to react differently to evidence of negative results versus null results.
While overall use of supplements has gone up, use of certain individual supplements has gone down, for example beta-carotene and vitamin E. This decline followed reports of studies that showed these could be harmful.
On the other hand, evidence that daily supplements have null effects - that is, they make no difference to health - appear to have no effect on consumers and overall sales have kept growing.
Three studies suggest no benefit to supplements
In one of the studies published in the same issue as the editorial, Dr. Francine Grodstein, of Harvard School of Public Health, and colleagues examined data from the The Physicians' Health Study II, to look at the effect of long-term use of multivitamins on cognitive health.
The participants were nearly 6,000 male doctors aged 65 and over, who were randomized to take either a daily multivitamin pill or placebo pill for 12 years.
Tests of memory and cognitive function showed no difference between the two groups, and the researchers conclude:
"In male physicians aged 65 years or older, long-term use of a daily multivitamin did not provide cognitive benefits."
In another study, researchers reviewed evidence on the use of vitamin and mineral supplements to prevent heart disease and cancer, in order to update the guidelines for the US Preventive Services Task Force - an expert panel that advises the US government.
Their review found "limited evidence" to justify regular supplementation with vitamins and minerals for the prevention of cancer and cardiovascular disease (CVD).
They also note that beta-carotene appears to increase risk of lung cancer in smokers.
And in the third study, researchers looked at the role of multivitamins and minerals in preventing a further heart attack, in more than 1,700 patients recruited at least 6 weeks after a heart attack (myocardial infarction).
Having a heart attack raises a person's risk of a further attack, stroke or death.
The patients were randomly assigned to receive either a daily high dose of multivitamins and minerals, or placebo pills for 5 years.
The study results showed no differences between the two groups in rates of chest pain, another attack, need for hospitalization, stroke or early death.
However, the authors note that these results should be treated with caution since not all participants took the pills as they should.
Strong reaction from the supplement industry
The Council for Responsibile Nutrition (CRN), a group that represents the supplement industry, has voiced strong objections to the editorial.
They argue that while it is all very well to say instead of taking supplements people should concentrate on eating a healthy diet and exercising, this "fantasy" vision fails to recognize "real life."
Steve Mister, CRN's President and CEO, says:
"The editorial demonstrates a close-minded, one-sided approach that attempts to dismiss even the proven benefits of vitamins and minerals. It's a shame for consumers that the authors refuse to recognize the real-life need for vitamin and mineral supplementation, living in a fairy-tale world that makes the inaccurate assumption that we're all eating healthy diets and getting everything we need from food alone."
He says while not suggesting supplements are a panacea, he hopes the authors agree they have their place, especially as government studies show consumers are repeatedly failing to eat a healthy diet.