Taking a multivitamin every day doesn't seem to ward off
thinking and memory problems. Nor will it prevent further heart disease or
death among people who have already had a heart attack.
Those findings come from two reports published in the Annals
of Internal Medicine.
The studies represent the latest in a growing body of
evidence suggesting the popular supplements probably aren't doing most users a
lot of good. "People over time and particularly people in the United States
have been led to believe that vitamin and mineral supplements will make them
healthier, and they're looking for a magic pill," Dr Cynthia Mulrow said.
But such a pill doesn't exist, said Mulrow, a senior deputy
editor at the journal who co-wrote an editorial published with the new
research."People... should be active, should not (overeat), should
avoid excessive alcohol and should not be spending money on these pills, these
vitamins and minerals," she told Reuters Health.
No effect on heart disease
The studies follow a review of earlier research published
online last month. It found multivitamins had no effect on heart disease and
possibly a small effect on cancer risk, but only among men.
To look at whether vitamins affect thinking and memory
skills, researchers randomly assigned about 6 000 older male doctors to take
either a standard multivitamin or vitamin-free placebo as part of a larger
men's health study. Then they gave the men up to four memory tests over the
next 12 years.
Howard Sesso from Brigham and Women's Hospital in Boston and
his colleagues found no cognitive differences between the vitamin and placebo
groups at any time point. Nor did scores on the memory tests drop any faster
among men in one group versus the other.
The second new study included both men and women who'd had a
heart attack. About 1 700 of them were randomly assigned to take supplements, this
time high doses of vitamins and minerals – or placebo pills.
Over an average of four and a half years, 27% of people
taking vitamins died or had another heart attack or other cardiovascular problem.
That compared to 30% of participants taking placebos, a difference that could
have been due to chance.
People in that study had to take six vitamin pills a day and
many weren't so good about sticking to that regimen, researchers led by Dr
Gervasio Lamas of the Mount Sinai Medical Centre in Miami Beach, Florida,
That could have
influenced the results. "As of now, there is no need to be taking
multivitamins and multiminerals to prevent heart disease and there is extensive
evidence on that," Lamas told Reuters Health.
"For the general population who (is healthy) and they
are taking vitamins because they are thinking that somehow the vitamins are
going to make them do better, people are entitled to waste their money in any
way that they like," he said.
Americans spent $28 billion on supplements in 2010, Mulrow
and her colleagues noted. Neither study found side effects tied to multivitamin
use. So people probably aren't hurting themselves by taking multivitamins,
especially in standard doses, researchers said.
Sesso said because of the possible cancer-related benefits
tied to multivitamins, they are still worth considering – in particular for
people who may not get enough vitamins in their diet.
A prior study by his team found an 8% lower risk of cancer
among men assigned to take multivitamins, as well as a lower risk of
cataracts."We really need to manage our expectations about why we're
taking multivitamins," Duffy MacKay, vice president of scientific and
regulatory affairs at the Council for Responsible Nutrition (CRN), said.
CRN is a Washington, DC, based trade group that represents
dietary supplement manufacturers and ingredient suppliers. He said the main
reasons people report talking multivitamins are for overall health and wellness
and to fill nutrient gaps.
Research shows Americans often don't get all recommended
nutrients from their diets, and that a multivitamin helps fill those gaps,
MacKay told Reuters Health. "That's reason alone that a multivitamin should
be consumed," he said.
"It's ultimately an individual decision," Sesso told
Reuters Health. Considering how many people take multivitamins – up to half of
all US adults – he said there's still a need for more research on their effects.
Mulrow had a different perspective. Based on the research
that has been done and the lack of general benefit, she questioned whether any
more money should be spent on studying vitamin supplements. "We think we
shouldn't be doing a lot more studies on most of these," she said.