Knowledge about dietary supplements and trust in advertising them: Development and validation of the questionnaires and preliminary results of the association between the constructs

Abstract

Background Despite offering little overall benefit and emerging concerns about their safety, dietary supplements have become increasingly popular. Trust in advertising them may contribute to high confidence in dietary supplements in public opinion. Aim To develop and validate a screening questionnaire intended for the general public regarding knowledge about dietary supplements and a questionnaire on trust in advertising dietary supplements, and to identify the association between these constructs. Materials and methods The development and validation of the measures was overseen by the panels of experts. The conceptual frameworks of the constructs were scientifically well grounded. A set of semi-structured interviews and anonymous web-based surveys was performed. The final questionnaire was applied to 220 non-medically educated people and 121 medically educated people. Results A 17-item questionnaire on knowledge about dietary supplements and eight-item questionnaire on trust in advertising dietary supplements were developed. The measures presented satisfactory proof of validity, however, the psychometric properties of the questionnaire on knowledge were modest. Both the knowledge about dietary supplements in the study group and trust in advertising them were low. A significant negative relationship was found between knowledge about dietary supplements and trust in advertising them among the general public (Pearson’s r = -0.42, 95%CI: -0.52 to -0.30, p <0.0001). This association was especially pronounced in people who reported not taking dietary supplements (Pearson’s r = -0.61, 95%CI: -0.76 to -0.39, p <0.0001). Conclusions The extensive advertising of dietary supplements appears to be in conflict with promoting evidence-based knowledge about them, which raises substantial concerns for the public health. The results of the study are only preliminary and require further confirmation and exploration.

The Association Between Health Conditions, Consciousness, Involvement, and Knowledge and Dietary Supplement Intake among University Students in South Korea

“…Abundant information on DS products may confuse consumers, especially those who have low knowledge of these commodities. Many previous studies confirmed that knowledge level and health behaviors are irrelevant to consumers’ decision to purchase products [42]; that is, purchase is based on perceptions rather than objective evidence [1,43]. Hence, education that cultivates adequate knowledge about DSs is needed [43].…”

“…Therefore, although the DS users may have been aware of the potentially weak efficacy of DSs, they also held positive perceptions of the benefits of consuming these supplements. This positivity might have stemmed from advertisements that deliver highly persuasive messages in a fiercely competitive DS market [43]. The result can also be attributed to the DS users understanding that supplement consumption helps them keep pace with the demands of campus life [12], which is known to present easy access to rapidly available snacks, regardless of the health condition and consciousness of students.…”

Exploring the Effects of Product Knowledge, Trust, and Distrust in the Health Belief Model to Predict Attitude Toward Dietary Supplements

“…Various events have aroused consumers’ suspicions, such as DS recalls in the US due to contamination (FDA, 2018); the detection of sibutramine-adulterated weight-loss products in the EU, the US, China, Australia, and India (Hachem et al, 2016); and the discovery of adulterated DSs in the Netherlands (Biesterbos et al, 2019). Along these lines, Polish consumers who were knowledgeable about DSs were found to exhibit low trust in DS-related advertising (Karbownik et al, 2019). In China, meanwhile, 60% of consumers were found to distrust so-called health food (China Consumer Association, 2016).…”

The Impact of the COVID-19 Pandemic on the Composition of Dietary Supplements and Functional Foods Notified in Poland

“…Consumer safety concerns connected with possible adverse effects of supplementation appeared parallel to the above conclusions [35]. These concerns may be exacerbated by the fact that marketing of supplements seem to be at odds with promotion of evidence-based knowledge [36].…”