A Literature Review of Dietitians’ Knowledge, Attitudes and Opinions towards Dietary Supplements

Abstract

Background: Since the late 1990’s, public interest and use of dietary supplements has dramatically increased despite the evidence supporting the use of dietary supplements being largely inconclusive, NHS Choices [1]. Various reports indicate that the public have insufficient knowledge of dietary supplements to enable them to use them safely and effectively, Miller and Russell [2]. With the lack of public knowledge of dietary supplements already recognised, dietitians play a critical role in offering impartial advice based on the best available evidence to support the public in making informed decisions in the use of dietary supplements. The aim of this review was to consider dietitians’ level of knowledge and the stance they take towards dietary supplements. For this purpose, a dietary supplement is the collective term used to describe both nutrient-based dietary supplements and herbal-based dietary supplements. Methods: A literature search focussed on journal articles published in English between January 2000 and February 2013, in the following databases; Proquest, Science Direct and EBSCO Host searching; Ahmed, Cinhal and Medline. A combination of the following search terms were used; ‘dietitian(s)’, ‘dietician(s)’, ‘knowledge’, ‘attitude(s)’, ‘opinion(s)’, ‘perception(s)’, ‘belief(s)’, ‘dietary supplement(s)’, ‘nutraceutical(s)’, ‘vitamin(s)’, ‘mineral(s)’ and ‘herb(s)’. Ten primary research articles pertinent to the aim of this study were selected for inclusion from a total of 483 articles which were retrieved from this search and one other from an unrelated ‘Google’ search. Results: The eleven studies were of cross-sectional design. Nine studies conducted their research across various states of America, with one extending to Germany, Hungary and Canada, one focussed their research in Canada; and one in the Netherlands. Each study carried out their research using a questionnaire, in one of the following formats; postal, email, online or telephone survey; with the number of eligible subjects ranging from 57 to 1,268. Discussion: Dietitians have a greater knowledge of nutrient-based dietary supplements than herbal-based dietary supplements, Lee et al. [3]. Findings suggested dietitians are more knowledgeable on the intended use of dietary supplements and least knowledgeable on the pharmacological effects and risks of these products, including supplement-drug interactions and side effects. A greater knowledge was positively associated with the personal use of dietary supplements and specifically of the particular products used. Dietitians’ knowledge, attitudes and opinions were reflected in their recommendations for use of dietary supplements in practice. There was a recognised need among dietitians for further training regarding dietary supplements. Conclusion: It can be concluded that dietary supplements warrant further recognition within the dietetic curriculum and also within the practice setting. In addition, there is a general consensus that advising patients on dietary supplements should be a shared responsibility between the multi-disciplinary team. Further Recommendations; A standardised tool is developed to further explore this subject area, within the European dietetic population.