Dietary supplements: the life elixir of the 21st century. A longitudinal survey study identifying relevant socio-cognitive determinants of dietary supplement use

Helping and protecting consumers of dietary supplements by giving ‘the necessary information to make choices in full knowledge of facts’ has been an important issue on the agenda of the European Food Safety Authority... [ view full abstract ]

Helping and protecting consumers of dietary supplements by giving ‘the necessary information to make choices in full knowledge of facts’ has been an important issue on the agenda of the European Food Safety Authority lately. In the Netherlands, the prevalence of dietary supplement use has doubled (from 17 to 40 percent) since the 1980’s and a similar trend is visible worldwide. However, there is still no scientific consensus regarding the benefits of dietary supplement use at population level. Therefore, effective risk-benefit communication is needed to help consumers make an informed decision regarding dietary supplement use.

When developing communication strategies, a clear understanding of consumers’ decision making process behind the use of supplements is of major importance. For investigating individuals’ motives for engaging in dietary supplement use, the Integrated Change Model (ICM) was used as theoretical framework.

Socio-cognitive determinants were measured in a longitudinal survey study, with measurements at baseline (N= 1448) and 1 month follow-up (N= 1161). Negative binomial regression analyses were applied.
Results showed that supplement use was mainly predicted by intentions, health regulatory focus (promotion), social modelling, and attitude (pros). Additional determinants, albeit with smaller effect sizes were: attitude (cons), health locus of control (external), and risk perception.

Contrary to the expectations, prevention oriented individuals were not more inclined to take dietary supplements. A peculiar finding considering the fact that increased risk perceptions towards getting ill significantly predicted supplement use. In addition, social modelling emerged as one of the most important determinants of dietary supplement use. Also, evidence was found, that individuals engage less in dietary supplement use when they do not feel being able to control their own health.

Based on the results, implications for risk-benefit communication will be discussed and important issues will be addressed, such as: what is dietary supplement users’ socio-cognitive profile, what (and how) factors should be targeted with communication about dietary supplements, which way influential factors alter the manner individuals weigh up risks and benefits against each other, how could legislation on claims be improved to stimulate consumers’ informed decision making.