The scientists, from National Sun Yat-Sen University, were looking for whether the supplements might cause people to make poor health-related choices as an ironic consequence of believing the supplements would protect them. Wen-Bin Chiou decided to do the study when he noticed a co-worker who chose an unhealthy meal. The colleague claimed as a defense that he took a multivitamin that 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,” Chiou said.
Chiou, Chao-Chin Yang of National Kaohsiung University of Hospitality and Tourism, and Chin-Sheng Wan of Southern Taiwan University had participants in Group A take a multivitamin while participants in the control group were assigned to take a placebo.
However, all the participants took placebo pills.
The study, scheduled to be published in the journal Psychological Science, says 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.
In summary, dietary supplement users may believe 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, Chiou said.