Herbal Supplement Use for Evidence-Based Indications in US Adults: An Analysis of National Survey Data

Understanding the changes in consumer use of herbal products and what has influenced these changes is key in the promotion of evidence informed use. The last analysis of evidence informed herbal supplement use involved the 2002 National Health Interview Survey (NHIS) analysis. This study reproduces and expands upon that earlier analysis, with the most recent NHIS dataset to report herb use patterns. It also explores the guiding resources consulted by consumers in their decision to use. Secondary analysis of cross-sectional data from the NHIS identified the 10 herbal supplements with the most reported use in 2012. The reasons reported by the NHIS for taking herbal supplements were compared with the 2019 Natural Medicines Comprehensive Database (NMCD) to determine whether reasons cited in consumption were supported by evidence. Logistic regression models were fit according to NHIS sampling weights to examine the relationship between evidence-based use and user characteristics, guiding resources, and health care professional engagement surrounding use. Of the 181 reported uses of herb supplements for a specific health condition, 62.5% were for reasons supported by evidence-based indications (EBIs). The odds of herb use consistent with evidence significantly increased for those reporting higher education status (odds ratio [OR] = 3.01, 95% confidence interval [CI] [1.70-5.34]). Herbal supplement use consistent with EBIs was more likely among those who disclosed their herb use to a health care professional (OR = 1.77, 95% CI [1.26-2.49]). Evidence-based herb use was also less frequently informed by Media sources (OR = 0.43, 95% CI [0.28-0.66]) compared with non-EBI use. Approximately 62% of the reasons cited for taking the most consumed herbs in 2012 were in alignment with 2019 EBIs. This increase may be due to improved awareness of health care professionals and/or an increase of evidence for traditional uses of herbal products. Future research should explore the role of each of these stakeholders in improving evidence-based herb use in the general population.