expert opinion

Dietitians and dietary supplements

May 15, 2012


Leslie Bonci, Director of the Sports Nutrition Program at the UPMC Center for Sports Medicine, University of Pittsburgh, USA

“National nutrition surveys show that many Americans fall short in the consumption of several vitamins, minerals and trace elements, including vitamins A and D, vitamins C and E, and vitamin B6, calcium, zinc, magnesium, and iron (1,2). The Academy of Nutrition and Dietetics (formerly the American Dietetic Association) urges improvement in overall dietary habits as the primary tool for improving nutrient intake, but the organization’s position paper on nutrient supplementation also recognizes that dietary supplements may have a role to play in helping people achieve nutritional goals (3). The Dietary Reference Intakes established by the Institute of Medicine suggest supplemental intakes of some nutrients for some population groups, such as folic acid for women of childbearing age and vitamin B12 for people over the age of 50, and the 2010 Dietary Guidelines for Americans also incorporate these recommendations (4,5). The National Osteoporosis Foundation recognizes that some people may need supplemental intakes of calcium and vitamin D to reach levels considered to be necessary to build and maintain optimum bone mass during growth and early adulthood and to reduce bone loss during aging (6). Long chain omega-3 fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are consumed at very low levels by most Americans, and increased intake could improve cardiovascular health and also provide other benefits (7).

Dietary supplement use is common among US adults, with more than half of the population using such products (8). Surveys show that usage is higher among older adults than among young adults, higher among women than among men, and increases with one’s level of education. Most dietary supplement users say their primary moti-vation for taking supplements is to improve their overall health and wellness, or to fill perceived nutrient gaps in their dietary intake (9). Less attention has been paid to usage among health professionals and to whether they recommend dietary supplements to their patients or clients. In earlier studies, regular dietary supplement use was reported for over 70% of dietitians and nurse practitioners; around 60% of pharmacists and dermatologists; about 50% of family care physicians, gynecologists and orthopedists; and 37% of cardiologists (10,11).

A new survey was conducted to examine the extent to which dietitians use dietary supplements or recommend these products to their clients. The study included 300 dietitians (96% female, 84% in the age range 30 to 59, geographically dispersed across the US) who were asked in an online survey, if they use and/or recommend dietary supplements. The results showed that

  • 96% of the dietitians surveyed said they had used a dietary supplement during the previous year (74% regular-ly, 20% occasionally and 2% seasonally). 3% said they had used supplements in the past but no longer did so, and only 1% said they had never used dietary supplements;
  • among the dietitians who said they used dietary supplements at least some of the time, 43% had taken them for four to ten years, 20% had taken them for 11 to 20 years, and another 20% had taken them for over 20 years. Only 16% had taken them for three years or less;
  • the top three reasons for taking dietary supplements were for bone health (58%), for overall health and well-ness benefits (53%), and to fill nutrient gaps in the diet (42%);
  • 84% of the dietitians saying they had taken a multivitamin within the past year, compared to 63% who had taken calcium, 47% who had taken omega-3 or fish oil supplements, 43% who had taken vitamin D, 29% who had taken vitamin C and 23% who had taken B vitamins.

When asked if they ever recommend dietary supplements to clients, 97% of the dietitians surveyed said they did. There was no significant difference in the prevalence of recommending dietary supplements according to age, region or years in practice. The top reasons for recommending dietary supplements to their clients were bone health (70%), filling nutrition gaps (67%), overall health and wellness benefits (49%), lowering cholesterol (46%), heart health (46%), dietary pattern/vegetarian/vegan (43%), digestive or gastrointestinal health (39%), diabetes or glucose control (27%), and eating disorders (19%).

While authoritative groups consistently encourage a ‘food first’ approach to achieving nutrient adequacy, it is also recognized that most people have dietary intakes that fall short in some respects and that dietary supplements can make a contribution toward achieving nutritional goals. Dietitians are uniquely qualified to evaluate the adequacy of nutrient intake and to make rational choices about dietary supplement use for themselves and for their clients or patients, when appropriate.”

Based on: Dickinson A. et al. Dietitians use and recommend dietary supplements: report of a survey. Nutrition Journal. 2012; 11:14.


  1. Moshfegh A. et al. What we eat in America, NHANES 2001–2002: Usual nutrient intakes from food compared to Dietary Reference Intakes: U.S. Department of Agriculture. Agriculture Research Service. 2005.
  2. Moshfegh A. et al. What we eat in America, NHANES 2005–2006; Usual nutrient intakes from food and water compared to 1997 Dietary Reference Intakes for vitamin D, calcium, phosphorus, and magnesium: U.S. Department of Agriculture. Agriculture Research Service. 2009.
  3. Marra M. V. and Boyar A. P. Position of the American Dietetic Association: nutrient supplementation. J Am Diet Assoc. 2009 ; 109(12):2073–2085.
  4. Institute of Medicine: Dietary Reference Intakes: The Essential Guide to Nutrient Requirement. Washington, D.C.: National Academies Press. 2006.
  5. Department of Agriculture and Department of Health and Human Services: Dietary Guidelines for Americans, Seventh Edition. In Washington, D.C.: Government Printing Office. 2010.
  6. National Osteoporosis Foundation: Calcium: What you should know. (Accessed July 2011
  7. Harris W. S. et al. Towards establishing dietary reference intakes for eicosapentaenoic and docosahexaenoic acids. J Nutr. 2009 ; 139(4):804–819.
  8. Bailey R. L. et al. Dietary supplement use in the United States, 2003–2006. J Nutr. 2011 ; 141(2):261–266.
  9. Dwyer J. Why do Americans use dietary supplements? Presentation at American Dietetic Association Food & Nutrition Conference and Expo (FNCE). October 24, 2005.
  10. Dickinson A. et al. Physicians and nurses use and recommend dietary supplements: report of a survey. Nutr J. 2009 ; 8:29.
  11. Dickinson A. et al. Use of dietary supplements by cardiologists, dermatologists and orthopedists: report of a survey. Nutr J. 2011 ; 10:20.