Nutrition 411: Multivitamin Supplements - Magic Bullet or Waste of Money?

   Most wound care practitioners are familiar with the relationship between appropriate nutritional care and wound healing. We strive to meet each patient’s needs for protein, calories, fluids, vitamins, and minerals in order to provide the necessary substrate to fuel the wound healing process. Quite often, multivitamin supplements are prescribed with the belief they will hasten wound healing with little risk of adverse effects. In fact, more than 115 million Americans use dietary supplements; sales exceeded $17 billion in 2000.¹ Is this practice safe? Is it effective? Unfortunately, the answers are not clear-cut. In fact, an indepth look at the issues raises more questions than it answers.

Questions about Multivitamin Supplements

  There is growing concern in the medical community about the safety of dietary supplements.² Many foods and liquid nutritional supplements are fortified with significant doses of vitamins and minerals, making additional multivitamin supplements unnecessary in some cases and unsafe in others. Potential adverse effects of over-supplementation include poor absorption of nutrients or medications, both prescription and over-the-counter. The supplement industry is not well regulated. Thus, experts question whether doses listed on supplement labels are accurate. Clinicians ponder whether supplement manufacturer (generic versus name brand) or form (liquid versus tablet) is important.

  The contents of multivitamins and multivitamins with minerals can vary tremendously. Table 1 compares two similar common brand name multivitamin supplements. A quick glance at the ingredient list reveals many substantial differences; discerning whether they make a difference in one’s health is difficult. The price between the two brands is also substantially different. With all this in mind, selecting the ideal supplement can be daunting. Hospitals and long-term care facilities use “stock multivitamins.” Reviewing exactly what the stock vitamin contains and seeing how it compares to common national brands is a worthwhile endeavor. Understanding these issues and knowing exactly what you are prescribing before including supplements in your wound care protocol is critical.

Vitamin Supplement Labeling

  The Dietary Supplement Health and Education Act of 1994 (DSHEA) established the foundation for regulations for all dietary supplement labeling, including multivitamins, herbs, and botanicals. Under these rules set forth by the US Food and Drug Administration (FDA), testing and label verification is not the same for supplements as for foods and medications. In 2007, the FDA issued Good Manufacturing Practices (GMPs) for dietary supplements. Under these guidelines, manufacturers are expected to guarantee the identity, purity, strength, and composition of their supplements. GMPs state that the labels of dietary supplements are required to be truthful and not misleading, but FDA testing for contents and/or labeling accuracy is not required.³ Table 2 outlines the regulatory oversight of drugs and dietary supplements in the US.

  Data comparing analyzed with declared label values in many marketed vitamin products are relatively scant.³ When products have been independently analyzed, supplements have been found to contain both more and less of the nutrients stated on the label.⁴ Because of inconsistent manufacturing standards, some hospitals have banned use of certain dietary supplements.⁵ Pharmacy directors in acute care settings have reported concerns about the consistency of dietary supplement formulations and the lack of FDA review of supplements.⁵ Supplement manufacturers can pay voluntarily to have independent organizations such as US Pharmacopeia (USP) or NSF International evaluate their supplement quality and contents and ensure they are adhering to GMPs.^6,7 The USP or NSF International designation on a supplement label indicates the supplement meets their guidelines but does not address safety or efficacy. Unless a brand carries a USP or NSF International insignia on its label, it is difficult to know if any specific brand is better than another.

Nutrient Bioavailability in Supplements

  Many vitamin manufacturers claim their products are more quickly or easily digested or absorbed because of their form (liquid versus solid) or ingredients. However, nutrient bioavailability in supplements is affected by many factors, not just form.4 Fillers and coatings used in supplement preparations can affect rate of dissolution or absorption. One chemical form of a nutrient (for example, vitamin D2 versus D3) may be more available than another. Factors in the host also can have an effect on nutrient bioavailability, including homeostatic mechanisms that affect circulating levels of nutrients, the dose of the supplement, and interactions with other medications or other nutrients in the digestive tract. Because so many variables are involved in nutrient digestion and absorption, no one is certain if different forms or brands of vitamins facilitate better, faster, or more complete nutrient absorption. Liquid vitamins may be easier to consume and more quickly or easily absorbed for some patients but little scientific evidence is available to support their benefit compared to capsules or tablets. Table 3 describes the steps of a home test to mimic lab testing of absorbability by simulating the acidic environment of the gut.

Are Supplements Recommended for Wound Healing?

  Prospective, randomized clinical trials on the safety and efficacy of dietary supplements are lacking.² Wise selection of nutrient-rich foods is generally the best strategy for meeting nutrient needs.⁷ However, some groups are vulnerable to inadequate nutrient intake as a result of lack of variety in the diet, poor appetite, or illness.⁸ Vitamin supplements may be necessary to make up for increased needs or inadequate intakes in some population groups.⁸ Because micronutrients play a significant role in wound healing, multivitamin supplements can be beneficial in patients with pressure ulcers or chronic wounds. Vitamin and mineral supplements should be offered to a patient with a pressure ulcer when dietary intake is poor or a deficiency is confirmed or suspected.⁹

  Multivitamins with minerals such as iron or zinc should be used with caution because of possible over-supplementation or potential drug/nutrient interactions. For example, excess zinc can interfere with copper absorption.¹⁰ If a patient is taking minerals such as iron or zinc, the addition of a multivitamin with minerals ordered for the treatment of a pressure ulcer could contribute to zinc overload or adverse drug/nutrient reactions. It is important to look at the daily total intake from both food and supplements.

  A thorough nutrition assessment can help identify a nutrition diagnosis related to inadequate micronutrient intake or increased micronutrient needs. Information on all medications, herbs, vitamin supplements, medical nutrition supplements, and fortified foods should be obtained to get a complete picture of nutrient intake. A nutrition-focused physical exam that includes examining the hair, nails, mucous membranes, skin turgor, weight history, and dental status can help identify nutrient deficiencies. If deficiencies are suspected, a laboratory test may be ordered to confirm the finding and monitor response to supplementation.

Practice Points

• Unlike with food and medications, the FDA does not require testing to ensure vitamin supplement contents are accurately listed on the label.
• Bioavailablity of nutrients is affected by many factors. As a result, it is unclear if liquid, tablets, or caplets are best.

• Many patients with chronic wounds may benefit from a multivitamin supplement without risk of harm, especially if they are not eating a well-balanced diet. However, medical professionals should use their clinical judgment when recommending supplements to minimize risks of over-supplementation or drug/nutrient interactions.

For more indepth information on supplements, visit: National Center for Complementary and Alternative Medicine: https://nccam.nih.gov/ Office of Dietary Supplements: https://dietary-supplements. info.nih.gov/ Office of Dietary Supplements Dietary Supplements Ingredient Database: www.Dietarysupplementdatabase.usda.nih.gov U.S. Food and Drug Administration: www.fda.gov/Food/DietarySupplements/default.htm

Coming Next Month: Dealing with Nonadherent Patients

Correspondence may be sent to Dr. Collins at NCtheRD@aol.com. 

This article was not subject to the Ostomy Wound Management peer-review process.

1. USFDA. FDA overview: dietary supplements, infant formulas, cosmetics. Available at: www.emedicinehealth.com/script/main/ art.asp?articlekey=59287&pf=3&page6. Accessed April 17, 2010.

2. Sadovsky R, Collins N, Tighe AP, Brunton SA, Safeer R. Patient use of dietary supplements: a clinician’s perspective. Curr Med Res and Opin. 2008;24(4):1209–1216.

3. US Food and Drug Administration. Dietary Supplements. Available at: www.fda.gov/Food/DietarySupplements/default.htm. Accessed March 31, 2010.

4. Yetley EA. Multivitamin and multimineral dietary supplements; definitions, characterizations, bioavailability, and drug interactions. Am J Clin Nutr. 2007;85(suppl 2):69S–76S.

5. Bales CW, Ritchie CS. Handbook of Clinical Nutrition and Aging, 2nd ed. New York, NY: Humana Press, 2009.

6. U.S. Pharmacopeia. The USP Dietary Supplement Verification Program. Available at: www.usp.org/SUPVerified/dietarySupplments/. Accessed April 1, 2010.

7. NSF International. Dietary Supplements and Functional Foods. Available at: www.nsf.org/business/dietary_supplements/ index.asp?program=DietarySups. Accessed April 1, 200.

8. Position of the American Dietetic Association: Nutrient supplementation. J Am Diet Assoc. 2009;109:2073–2085.

9. Dorner B, Posthauer ME, Thomas D. The Role of Nutrition in Pressure Ulcer Prevention and Treatment: National Pressure Ulcer Advisory Panel White Paper. National Pressure Ulcer Advisory Panel, 2009. Available at: www.npuap.org/Nutrition%20White%20Paper% 20Website%20Version.pdf. Accessed April 1, 2010.

10. Litchford MD. The Advanced Practitioner’s Guide to Nutrition and Wounds. Greensboro, NC: Case Software, 2009.