Are Women's Supplements and Vitamins Useful?

Although eating a balanced, healthy, and varied diet is the best way to meet nutritional needs, multivitamin/multimineral (MVM) supplements are often used by many women as they move through life.

Americans have been taking MVM supplements since they became available in the early 1940s, and they account for an estimated 40% of all vitamin and mineral sales in the United States, according to the National Institutes of Health’s Office of Dietary Supplements.^1-3

However, there is limited evidence that MVM supplements offer significant health benefits.2 Some study results suggest potential adverse effects or benefits, while others have found none.²

There are a host of MVM supplements on the market for pregnant women, teen girls, those younger than 50, those older than 50, and women during menopause.

According to the US Office on Women’s Health, women who consume a balanced, healthy diet may not need MVM supplements, but there are 3 groups that could benefit⁴:

• Postmenopausal women. After menopause, women lose bone density faster than men due to hormonal changes. Because many women do not get enough calcium and vitamin D from their diets, they may need supplements of these to help prevent osteoporosis. They may also need to take supplements with vitamin B-12.⁴
• Vegetarians. Many people get some vitamins from animal products more easily than from plant sources, such as vitamin B-12, which is not found in plants. Vegans especially may not get enough vitamins B-2, B-12, and D from food alone.⁴
• Those who are pregnant or could become pregnant. These women need folic acid to prevent certain birth defects.⁴

Pharmacists can be instrumental in providing women with the most recent clinical data about MVMs; in assessing their medical and medication profiles to ascertain if they are at risk for certain nutritional deficiencies or toxicities, because of possible drug/ nutrient interactions; and in guiding in their proper selection of MVMs.

RECENT CLINICAL STUDIES AND NEWS

In a survey conducted by the Council for Responsible Nutrition, more than 75% of US adults reported taking OTC supplements.⁵ The most popular supplements were MVMs, which—although unproven to produce health benefits for most individuals—are likely harmless if taken in doses comparable to the National Academy of Sciences’ dietary reference intake recommendations.^6,7

A systematic review of existing data and single randomized control trials from January 2012 to October 2017, published in the May 2018 issue of the Journal of the American College of Cardiology, found that multivitamins, vitamin D, calcium, and vitamin C, the most common supplements, showed no added risk or advantage in the prevention of cardiovascular disease (CVD), myocardial infarction, premature death, or stroke.⁸ However, the study found that folic acid alone and B vitamins with folic acid may diminish the risk of CVD and stroke.

Study results published in the April 2019 issue of Neurology, showed that researchers investigated the association between the intake of minerals, such as calcium, copper, iron, magnesium, manganese, phosphorus, potassium, and zinc, and multiple sclerosis (MS) risk.

Previous study results suggested that these minerals may contribute to MS activity and progression.^9,10 These study results found that there was no association between the minerals and MS risk, either for baseline or cumulative intake during follow-up. The associations were null when comparing women with the highest intakes to those with the lowest mineral intakes.^9,10

Another study published in the April 2019 issue of Annals of Internal Medicine linked supplemental doses of calcium exceeding 1000 mg/day to an increased risk of cancer death.^11,12 The researchers concluded that adequate intake of certain nutrients from foods, not supplements, is associated with a reduction in all-cause mortality. Additionally, the study found that the lower risk of death from CVD associated with adequate intakes of vitamins A and K, and zinc, was limited to nutrients from foods, not from supplements. There was also no association between dietary supplement use and a lower risk of death.^11,12

THE PHARMACIST’S ROLE

Nutritional supplements may help women meet their dietary needs, especially in patients at greater risk for nutritional deficiencies because of the use of pharmacological agents or medical conditions that may deplete or make it more difficult to absorb certain nutrients. As frontline health care providers, pharmacists can be instrumental in counseling women about the various supplements formulated to meet their nutritional needs at various stages of their lives. During counseling, pharmacists should remind patients that nutritional supplements should never be a substitute for a balanced and healthy diet. Additionally, patients should be encouraged to only use supplements from reputable manufacturers. Because of their drug expertise, pharmacists can identify possible drug/nutrient interactions and advise patients who elect to take these supplements to only take the recommended doses. Although the debate about the use of nutritional supplements is ongoing and more study is warranted, pharmacists can empower women with the most recent efficacy and safety clinical data to make informed decisions about their health.

Yvette C. Terrie, BSPharm, RPh, is a consulting pharmacist and a medical writer in Haymarket, Virginia.

REFERENCES

• National Institutes of Health State-of-the-Science Panel. National Institutes of Health state-of-the-science conference statement: multivitamin/mineral supplements and chronic disease prevention. Am J Clin Nutr. 2007;85(1):257S-264S. doi: 10.1093/ ajcn/85.1.257S.
• Multivitamin/mineral supplements. National Institutes of Health website. ods. od.nih.gov/factsheets/MVMS-HealthProfessional/#en1. Updated July 8, 2015. Accessed April 10, 2019.
• Bailey RL, Gahche JJ, Lentino CV, et al. Dietary supplement use in the United States: 2003-2006. J Nutr. 2011;141(2):261-266. doi: 10.3945/jn.110.133025.
• Vitamins and minerals for women. Womenshealth.gov website. womenshealth.gov/ healthy-eating/how-eat-health/vitamins-and-minerals-women. Published October 18, 2018. Accessed April 10, 2019.
• 2017 CRN Consumer Survey on Dietary Supplements. Council for Responsible Nutrition website. crnusa.org/resources/2017-crn-consumer-survey-dietarysupplements. Accessed April 9, 2019.
• Moyer VA; U.S. Preventive Services Task Force. Vitamin, mineral, and multivitamin supplements for the primary prevention of cardiovascular disease and cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2014; 160(8):558-564. doi: 10.7326/M14-0198.
• Nutrient recommendations: dietary reference intakes (DRI). National Institutes of Health website. ods.od.nih.gov/Health_Information/Dietary_Reference_Intakes.aspx. Accessed April 9, 2019.
• Jenkins DJA, Spence JD, Giovannucci EL, et al. Supplemental vitamins and minerals for CVD prevention and treatment. J Am Coll Cardiol. 2018;71(22):2570- 2584. doi: 10.1016/j.jacc.2018.04.020.
• McNamara D. No influence of dietary supplemental minerals on MS risk. Medscape website. medscape.com/viewarticle/911476. Published April 8, 2019. Accessed April 9, 2019.
• Cortese M, Chitnis T, Ascherio A, Munger K. Total intake of different minerals and risk of multiple sclerosis. Neurology. 2019:92(18):e2127-e2135. doi: 10.1212/ WNL.0000000000006800.
• Chen F, Du M, Blumberg JB, et al. Association among dietary supplement use, nutrient Intake, and mortality among U.S. adults [published online April 9, 2019]. Ann Intern Med. 2019. doi: 10.7326/M18-2478.
• Nutrients from food, not supplements, linked to lower risks of death, cancer [press release]. Boston, MA: ScienceDaily. sciencedaily.com/ releases/2019/04/190408183720.htm. Accessed April 9, 2019.