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Vitamins and Supplements: Useful, or Harmful?

November 01, 2011

A recent article in the October 11 issue of The New York Times reported on two new studies that once again raise questions about the effectiveness and risks of taking vitamins and other dietary supplements:

  •  The Iowa Women’s Health Study, published in the Archives of Internal Medicine, followed 38,772 older women over a 19-year period (the mean age was 61.6 years at the baseline year in 1986). The study concluded that in older women, several commonly used dietary vitamin and mineral supplements, including multivitamins, may be associated with an increased mortality risk. The association was strongest with supplemental iron.
  •  A separate study of high-dose vitamin E and selenium use among 35,000 men, reported in The Journal of the American Medical Association, found that the vitamin users had a slightly higher risk of developing prostate cancer. (The doses studied in the trial were 200 micrograms of selenium and 400 international units of vitamin E, while most multivitamins contain only about 50 micrograms of selenium and 30 to 200 international units of vitamin E.)

“The problem is, we get confused by all the conflicting information about vitamins and other dietary supplements, since the data seem to change every week,” says Dr. Barbara Kostick, a family medicine specialist on the medical staff at Washington Hospital.

To help people learn more about the potential risks and benefits of vitamins and other dietary supplements, Dr. Kostick will be speaking at a Health & Wellness seminar sponsored by Washington Hospital on Tuesday, November 8 from 1 to 2:30 p.m. The seminar will be held in the Conrad E. Anderson, M.D. Auditorium at 2500 Mowry Avenue in Fremont.

At the seminar, Dr. Kostick will conduct a survey among participants to determine what questions they have regarding dietary supplements and address the most common concerns.  Possible areas of discussion may include:

  •  How do you know if you need a dietary supplement? Are there tests to determine if you have a nutritional deficiency?
  • Are there any dangers associated with taking dietary supplements?
  •  Can dietary supplements cause adverse effects or reactions with prescription medications?
  •  Are “natural” vitamins and supplements better and safer for you?
  • How safe and effective are herbal supplements such as St. John’s wort and ginkgo biloba? Is it safe to take herbal supplements that have a combination of ingredients?
  • Are “energy drinks,” “vitamin waters” or foods that contain supplements safe and beneficial?
  • How safe and effective are supplements that claim to help you lose weight or improve athletic performance?

“It’s true that some dietary deficiencies can cause certain diseases,” Dr. Kostick notes. “For example, not enough vitamin D can cause rickets, not enough vitamin C can cause scurvy, and not enough vitamin B1 (thiamine) can cause beriberi. These diseases were prevalent prior to the 20th Century when obtaining a nutritionally sound diet was more difficult, but most people don’t get these diseases anymore because we have better access to a variety of healthy foods.”

Multivitamin supplements were first introduced in 1934 by the Nutrilite Company, and they have been promoted ever since as ‘insurance’ for good health. The “shotgun” approach of taking a daily multivitamin, however, is not necessarily the best scientific approach.

“There really is not much data on the effectiveness of multivitamins – or most other dietary supplements – for primary prevention of disease, despite marketing myths that are not based on science,” Dr. Kostick says.

“On the other hand, some dietary supplements have been shown to be helpful,” she adds. “For example, taking folic acid during pregnancy can help prevent certain birth defects.  Proper doses of calcium and vitamin D can help prevent osteoporosis and bone fractures in post-menopausal women. Younger women with heavy menstrual periods may benefit from supplemental iron if they are anemic.”

Dr. Kostick suggests that rather than depending on a multivitamin, people should look at their own health risk factors and work with their physicians to develop individualized plans for taking only the supplements they need for the time of life they are in.

“The bottom line is that if you are healthy, chances are that you can get all the nutrients you need from eating a well-balanced diet, although you may need certain supplements for specific conditions,” she asserts. “Getting plenty of exercise helps, too. You can’t correct a lack of physical activity with a multivitamin.”

To register for the upcoming seminar on November 8, visit www.whhs.com.