This letter is a reaction to the paper by Chiou and others, in the December 2011 issue of Addiction, on how the use of dietary supplements may induce illusory invulnerability that, in turn, disinhibit smoking .
The findings run counter to other research findings of large population samples regarding healthy behaviors of individuals who consume dietary supplements regularly. Recent analysis of the US National Health and Nutrition Examination Survey (NHANES) data finds that dietary supplement use is associated with the avoidance of smoking among American consumers [2,3]. NHANES is a large government program designed to assess the health and nutritional status of adults and children in the United States. Furthermore, the Healthy Habits of Supplement Users and Non-Users survey found that a larger proportion of non-users smoke cigarettes (26% versus 15%, respectively) . Even if there is a potential ‘licensing’ effect that causes a small portion of dietary supplement users to smoke more, the large body of evidence suggests that this does not trump the overall healthier habits of supplement users, including full avoidance from smoking. This leads to the question that if individuals in the study took dietary supplements continuously (not just a placebo), would they be more prone to stop smoking and live healthier life-styles?
The outcomes of the study may not be generalized, as the prevalence and attitudes towards smoking are different in this subpopulation of undergraduate Taiwanese students. The study may have also induced bias among the participants, as it was not a blind study (the undergraduate students knew which treatment group they were in as well, as the proposed hypothesis of the study). The authors of this study should consider monitoring the long-term benefits of actual dietary supplement use in university students as a mechanism to help them develop healthier life-style habits.