Consumer Trust and Attitudes Towards Advertisements for Dietary Supplements

Background: The excessive use of dietary supplements is widespread, and their advertising is often misleading and suggests therapeutic properties. The aim of the study was to assess consumers’ perceptions of advertising, their expectations regarding the effects of dietary supplements, and their overall knowledge of these products. Methods: The study was conducted among 397 adults who were presented with the content of advertisements for four dietary supplements broadcast on Polish radio stations. Results: More than 67% of respondents had low or negligible knowledge of dietary supplements. Only 4.8% considered dietary supplements to be food products, whereas 40.3% believed them to be over-the-counter medicines. According to 45.7% of respondents, the advertisements created the impression that the efficacy of the products had been scientifically evaluated and proven. Furthermore, 74.1% believed that if the advertised dietary supplements did not have proven efficacy, such advertising was unfair and misleading. The largest proportion of respondents (41.1%) expressed moderate expectations regarding the efficacy of the advertised dietary supplements. Furthermore, the proportion of respondents expressing the highest level of scepticism increased with increasing knowledge of dietary supplements. Despite this, 60.6% of respondents declared that if they experienced the health problems referred to in the advertisement, they could be encouraged by it to start using such products. Factors that significantly increased the likelihood of dietary supplement use included high expectations regarding their efficacy (OR = 11.1), negligible knowledge about dietary supplements (OR = 2.9), the belief that their efficacy had been demonstrated in scientific studies (OR = 1.9), and residence in a rural area (OR = 1.9). Conclusions: Given forecasts of continued growth in the dietary supplement market, and the belief held by many consumers that the effects of such products have been proven, educational campaigns are needed to prevent them from being confused with medicines.