Vitamin Studies Spell Confusion for Patients
Oct. 14, 2011— -- If it's Monday, it must be bad news about multivitamin day -- or was that Wednesday? No, Wednesday was good news about vitamin D, not so good news about vitamin E -- if you're confused, join the club.
The alphabet soup of vitamin studies making headlines in the last few weeks has left more than one head spinning, and most clinicians scrambling for answers.
As the dust begins to settle, physicians interviewed by MedPage Today and ABC News agreed on a bit of simple wisdom -- a healthy diet is more important than a fistful of supplements.
Read this story on www.medpagetoday.com.
"I had already asked my patients to stop their vitamin supplements four to five years ago, with the exception of those with a deficiency of vitamin D, ... pregnant patients [who should get] folate and prenatal multivitamins, or those with cognitive impairment, when I would recommend a vitamin B complex," Albert Levy, MD, a primary care physician in New York, said in an email to MedPage Today and ABC News.
Whether patients heed the advice is another question, as recent research has shown that more take supplements now than ever before. More than half of Americans report taking a multivitamin or other dietary supplement, up from 40% just two decades ago.
And there's sure to be pushback from the largely unregulated dietary supplements market -- estimated to be a $20 billion industry -- which has already launched multiple critiques of the latest evidence.
Here's a sample of the supplement headlines over recent weeks: B12 deficiency leads to cognitive decline, vitamin D helps fight off tuberculosis, vitamin E ups the risk of prostate cancer, calcium won't improve outcomes for Mom or baby.
The one that garnered particular attention reported an increased risk of death in postmenopausal women taking multivitamins, as well as vitamin B6, folic acid, iron, magnesium, zinc, and copper.
Though multivitamins carried only a slightly increased mortality risk, many clinicians say they've written off the supplement for good.
That's because multivitamins were never recommended on the basis of strong evidence anyway, David Katz, MD, of Yale's prevention research center, told MedPage Today.
"What we had was a notion that this was an insurance policy," he said in an interview. "Many people don't eat the way they ought to, so they're not getting the optimal doses of nutrients from food. Instead, we can rely on a pill that ought to do you some good, and certainly couldn't do you harm. That was the thinking."
But more studies have suggested that the health outcomes in patients taking multivitamins appear to be slightly worse, Katz said.
Still, he cautions that the present study is merely observational and can't prove cause and effect. For instance, some patients may take supplements as a result of being diagnosed with a condition, or they take them because they have a family history of chronic disease and are trying to prevent it, he said.
And clinicians certainly are not concerned that taking multivitamins will kill their patients. It's just that there is no longer a dearth of evidence that they won't confer any harm at all, Katz said.
"Considering the weak basis for recommending multivitamins in the first place," he said, "when you combine that with evidence that maybe it could hurt, the rationale for making routine use of multivitamins goes away."
