Are dietary supplements working against you?

Do you belong to the one-half of the population that frequently uses dietary supplements with the hope that it might be good for you?

Well, according to a study published in an upcoming issue of Psychological Science, a journal of the Association for Psychological Science, there seems to be an interesting asymmetrical relationship between the frequency of dietary supplement use and the health status of individuals. Wen-Bin Chiou of National Sun Yat-Sen University decided to test if frequent use of dietary supplements had ironic consequences for subsequent health-related behaviors after observing a colleague chose an unhealthy meal over an organic meal simply because the colleague had taken a multivitamin earlier in the day.

"After reviewing the literature of the prevalence of dietary supplement use, it seemed to show that use of dietary supplements is increasing, but it does not appear to be correlated with improved public health," says Chiou who conducted the study along with Chao-Chin Yang of National Kaohsiung University of Hospitality and Tourism and Chin-Sheng Wan of Southern Taiwan University.

Two different experiments were conducted using a diverse set of behavioral measures to determine whether the use of dietary supplements would license subsequent health-related behaviors. Participants in Group A were instructed to take a multivitamin and participants in the control group were assigned to take a placebo. However, all the participants actually took placebo pills. The results from the experiments and survey demonstrated that participants who believed they had taken dietary supplements felt invulnerable to health hazards, thus leading them to engage in health-risk behaviors. Specifically, participants in the perceived supplement use group expressed less desire to engage in exercise and more desire to engage in hedonic activities, preferred a buffet over an organic meal (Experiment 1), and walked less to benefit their health (Experiment 2) than the control group.

What does this all mean? Per the results of the study, Chiou says, "People who rely on dietary supplement use for health protection may pay a hidden price, the curse of licensed self-indulgence. After taking dietary supplements in the morning, individuals should diligently monitor whether illusory invulnerability is activated by restored health credentials and subsequently licenses health-risk behaviors." To put it simply, people who take dietary supplements may have the misconception that they are invulnerable to health problems and may make poor decisions when it comes to their health – such as choosing fast food over a healthy and organic meal.

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For more information about this study, please contact Wen-Bin Chiou at wbchiou@mail.nsysu.edu.tw

The APS journal Psychological Science is the highest ranked empirical journal in psychology. For a copy of the article "Ironic Effects of Dietary Supplementation: Illusory Invulnerability Created by Taking Dietary Supplements Licenses Health-risk Behaviors" and access to other Psychological Science research findings, please contact Divya Menon at 202-293-9300 or dmenon@psychologicalscience.org.