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Questioning supplements: Is your daily multivitamin or dietary supplement necessary?

Network - Spring 2012

They come bearing pills. Bottles and bottles of pills.

Richard Lee, M.D., assistant professor in the Department of General Oncology and medical director of the Integrative Medicine Center at MD Anderson, says that about half of his consults involve patients asking about a variety of supplements. They want to know whether it’s OK to take them to boost their health and help them fight cancer.

The answer is often no.

Americans spend billions of dollars on them every year, but the industry is largely unregulated.

Is it time to start questioning our multivitamin and supplement use?

An increasing chorus of medical advice says yes.

What are supplements?

Richard Lee, M.D.

Lee defines them as products taken by mouth that contain a “dietary ingredient” intended to supplement the diet. Pretty vague, eh?

These ingredients include:

  • vitamins,
  • minerals,
  • herbs or other botanicals,
  • amino acids, and
  • substances such as
    • enzymes,
    • organ tissues,
    • glandulars, and
    • metabolites.

Simply put, Lee wants patients to think of supplements as medicines. Potent medicines.

“They’re largely unregulated, they may have adverse side effects, and they may interact negatively with other medications the patient needs to fight cancer,” he says.

He’s not against natural products, noting that they’re a common source of chemotherapeutic agents like vinblastine, which comes from periwinkle, and paclitaxel, derived from the bark of the Pacific yew tree.

Another physician raises a question

Holly Holmes, M.D.

Holly Holmes, M.D., assistant professor in the Department of General Internal Medicine, is another practitioner alarmed by the overuse of dietary supplements. A geriatrician and former pharmacist, Holmes says her elderly patients are often on a dozen or more medications.

When they ask her to help them streamline their meds, she often suggests eliminating the multivitamin. Patients are often surprised — and resistant.

Both Holmes and Lee say supplements, including vitamins and minerals, can have their place — if the patient is deficient in that vitamin or mineral.

“True vitamin or mineral deficiency is very uncommon,” Holmes says. “We just want to test some vitamins before recommending supplements, such as vitamin D or vitamin B12.”

Another area of concern is the unregulated nature of these supplements. Many assume that the U.S. Food and Drug Administration (FDA) regulates them for safety, but that’s not the case.

The passing of the Dietary Supplement Health and Education Act of 1994 put control back into the hands of the manufacturers. The FDA regulates supplements as a category of foods, not as drugs, and manufacturers are not required to get pre-approval from the FDA before they can enter the market.

The evidence isn’t there

In consultations with patients, Lee cites a host of respected research studies that cast doubt on the claims of supplement manufacturers. For example, there’s no definitive evidence that supplementation with any vitamin or mineral helps prevent cancer.

Instead, some vitamins may actually increase the risk of certain cancers. And some supplements may cause dangerous side effects.

There are things they can do to stay healthy, Lee assures his patients.

Eating a balanced and nutritious diet is a great start. For a guaranteed natural dose of vitamins, they should consume plenty of fresh fruits and vegetables.

And he advises them to increase their activity levels. Diet supplements don’t live up to the hype, but frequent moderate exercise — even broken up into several smaller increments — is a sure thing.

Lee remembers a patient who said he’d been taking supplements for years, and protested when Lee advised him to stop. Lee examined one of the bottles and saw that the product had expired five years earlier.

“If it has an expiration date, it’s not that natural,” he told the patient.

Most patients who come into the Integrative Medicine Center for a consultation usually end up taking his advice about eliminating supplements.

“I can take an hour with them, going through the research,” he says. “It usually convinces them.”

And what about Holmes, whose geriatric patients are often reluctant to give up their multivitamins?

“If they don’t believe me, I send them over to Dr. Lee,” she laughs.

Five-step program to wean off supplements

1. Come clean. Tell your medical team about all medications you’re taking. Better yet, bring them to your appointment.

2. Find out if you need the supplements. A simple blood screening can check your levels of important nutrients.

3. If you are deficient, aim for 100% — and no more — of recommended vitamins and minerals.

4. Strive to get essential nutrients the old-fashioned way, by eating a balanced diet including several fruits and vegetables daily.

5. Get up and move! Exercise is good for your emotional and physical health.

© 2015 The University of Texas MD Anderson Cancer Center