More On Supplements

Ask the DOC

Dietary supplementation, which I have written about before, is about a $30 billion industry in the U.S., with more than 90,000 products on the market. Recent national surveys have found that 52 percent of adults reported use of at least one product and 10 percent reported use of four or more products. Vitamins and minerals are among the most popular supplements and are taken by about 45 percent of adults to maintain health and prevent illness. Despite this enthusiasm, most studies of vitamin and mineral supplements have not demonstrated clear benefits for prevention of diseases that are not related to nutritional deficiencies. Indeed, some studies have found that taking these supplements in amounts that exceed the recommended dietary allowance (RDA), especially high doses of beta carotene, folic acid, vitamin E, or selenium, may have harmful effects including increased risk of death, cancer, and stroke.

Most clinicians advise patients to get vitamins and minerals from food instead of supplements. A healthy diet leads to positive health outcomes. Although routine nutrient supplementation is not recommended for the general population, targeted supplementation may be warranted in certain high-risk groups. Let’s look at some of these high-risk groups and recommendations for their dietary supplementation:

  • Pregnancy – folic acid and prenatal vitamins
  • Breastfed infants and children – vitamin D until weaned and iron from age 4-6 months
  • Older adults – vitamin B12, vitamin D and/or calcium
  • Bariatric surgery patients – fat-soluble vitamins, B vitamins, iron, calcium, zinc, copper, multivitamins/multiminerals
  • Pernicious anemia – vitamin B12 under the tongue or injected once a month
  • Crohn's disease, other inflammatory bowel diseases such as celiac disease – iron, B vitamins, vitamin D, zinc, magnesium
  • Long-term proton pump inhibitors (P.P.I.) (i.e. Nexium) - use vitamin B12, calcium, magnesium
  • Metformin – vitamin B12

When reviewing the use of vitamins and supplements with a clinician, it is important that the patient lists all that are taken. Some supplements may interfere with the efficacy of prescription medications (i.e. vitamin K and warfarin) or interfere with laboratory tests (i.e. biotin [vitamin B7] interferes with cardiac blood test results). Patient-friendly interaction checkers are available for free online (search for interaction checkers on, WebMD, or pharmacy websites). It is important to remember that the FDA is not authorized to check and review dietary supplements prior to their being marketed, however manufacturers are required to adhere to the FDA’s Good Manufacturing Practice (GMP) guidelines. The bottle label should state that the manufacturer adheres to the GMP guidelines. Also, consumers should select products that have been certified by independent testers such as, U.S. Pharmacopeia, NSF International, or Underwriters Laboratories (UL). These certified product testers ensure that the product contains the labeled dose(s) of the active medication(s) and does not contain heavy metals, microbes, or other toxins.

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