More than one-third of Americans take vitamin and mineral supplements daily. Despite the large sums of money consumers spend on dietary supplements, most know very little about these products. Typically self-prescribed, their use remains largely unregulated, underscoring the need for better consumer education.
What is a multivitamin/mineral supplement?
A multivitamin/mineral supplement (MVM) combines vitamins and minerals and perhaps even other ingredients, according to the National Institutes of Health Office of Dietary Supplements (NIH-ODS). The Agency for Healthcare Research and Quality defines MVMs as “any supplement containing three or more vitamins and minerals but no herbs, hormones, or drugs, with each component at a dose less than the tolerable upper level determined by the Food and Nutrition Board.” According to the NIH-ODS, MVMs, considered dietary supplements, account for more than 40 percent of all sales of vitamin and mineral supplements and $30 billion in the United States in 2011. Consumers should look for United States Pharmacopeia (USP) on the label to ensure that the supplement includes the declared ingredients with corresponding amounts, does not contain harmful levels of contaminants, will easily disintegrate and release into the body, and was made under safe and sanitary conditions.
Who takes them?
The NIH-ODS estimates that approximately one in four young children takes MVMs. Use declines, however, among adolescents, then increases again as they age. Nearly 40 percent of people age 71 and older take MVMs.
Other factors also impact use. Women and those with higher education, higher income, a healthier diet and lifestyle, and a lower body weight tend to employ MVMs more often. People in the western United States take them more often than their eastern counterparts. Certain ethnic and racial groups are less likely to take MVMs (including African Americans, Hispanics, and Native Americans). Smokers are also less likely to do so (NIH-ODS, 2013).
Why do people take them?
Many take MVMs to achieve the recommended dietary allowance for a vitamin or mineral for their particular age group, especially if they feel they cannot meet these recommendations by food alone. Others believe MVMs may prevent a particular disease. However, it is hard to know if one nutrient (or a combination of several) offers any long-term benefit or protection against disease, especially if that individual is also eating a healthy diet and follows other healthy lifestyle choices.
It is possible for people to meet all their nutrient needs with food if they follow a well-balanced diet that includes the recommended number of servings from the food groups for their age, gender, activity level, height, and weight. Those recommendations serve as a guideline to provide energy and ensure nutrient needs are met but not exceeded. Consumption of one food group does not crowd out another. In fact, the majority of food choices is nutrient-dense rather than empty calories. Many fad diets flaunt this healthy approach and focus on eliminating certain nutrients while consuming high quantities of others. These diets, not based on sound science, may be harmful. A diet should not be something people go on and off; it should be considered a lifestyle that includes all nutrients in moderation.
Too often, however, many patients misunderstand the idea of moderation. Children exposed to large portions, convenience foods, fast food, and fruit drinks or soda as their typical beverage have no basic concept of what a healthy eating pattern looks like and need further education to correct for the poor example set at home.
Who benefits from MVMs?
Several groups may benefit from taking MVMs. Women of childbearing age who might become pregnant should get 400 micrograms (mcg) of folic acid each day. This can be achieved by eating foods fortified with folic acid or through a dietary supplement. Once pregnant, a woman’s need for folic acid increases to 600 mcg per day. Most prenatal vitamin/ mineral supplements contain 800 mcg per dose. Folic acid, part of the vitamin B family, reduces the risk of neural tube defects in newborns. Pregnant women may also need an iron supplement. Iron helps carry oxygen in the blood, supports the enlarged blood volume expected during pregnancy, and provides for placental and fetal needs. Breastfed and partially breastfed infants should receive vitamin D supplements of 400 IU per day.
Postmenopausal women might also benefit from taking MVMs. After menopause, bone-mineral density drops significantly, and many health care providers recommend that these women supplement their diet with calcium and vitamin D to reduce fracture risk.
Men and women over age 50 who may not be able to meet their vitamin B12 needs should consider MVMs. Advanced age can decrease the ability to absorb this protein-bound nutrient. Pernicious anemia, a vitamin B12 deficiency caused by atrophic gastritis, or chronic stomach inflammation, can lead to irreversible neurological damage if left unchecked. The body must produce adequate hydrochloric acid in the stomach for the absorption of vitamin B12. Interestingly, gastritis, often brought on by infection from the chronic use of aspirin or other nonsteroidal anti-inflammatory medications, can contribute to reduced stomach acid production. Other individuals who should consider a vitamin B12 supplement include those who have had gastrectomy surgery, those who have undergone bariatric surgery for weight loss, and vegans.
The 1994 Dietary Supplement Health and Education Act (DSHEA) allows the Federal Drug Administration (FDA) to regulate dietary supplements similarly to food products rather than as drugs or food additives. Under DSHEA, dietary supplement manufacturers must provide safe and properly labeled products. However, the FDA bears the burden of demonstrating that a supplement is unsafe or mislabeled before it can restrict or ban a product. Dietary supplements are not subject to FDA premarket approval, which essentially makes consumers both the test market and the watchdog responsible for reporting any adverse effects to the FDA MedWatch. Consumers must also understand the potential for interactions between MVMs and certain drugs. For instance, vitamin K may interact with blood-thinning agents, such as Warfarin (Coumadin). Those with hypothyroidism should avoid taking an iron, calcium, or magnesium supplement at the same time as their thyroid medication, as it may interfere with the drug’s effectiveness.
Finally, dosage matters. The Food and Nutrition Board and Institute of Medicine of the National Academies set a tolerable upper intake level (UL) to define the maximum daily amount of a nutrient that appears safe for most healthy people. Too much of any vitamin or mineral can result in an increased risk of adverse effects. Consumers reduce these risks and maximize the benefits of dietary supplements by educating themselves through reputable sources and communicating with their health care providers. Use caution when self-prescribing any supplement and beware of product websites that claim to prevent, treat, or cure a disease. The best medicine is common sense.
Catherine R. Heinlein ’10, Ed.D., RN, PHN, RD, CDE, is a registered dietitian, registered nurse, and assistant professor in APU’s School of Nursing. For more information about meeting your nutrient needs, email her at firstname.lastname@example.org.