Dietary Supplement Use Among Adult Cancer Survivors in the United States

Background: Many cancer survivors initiated dietary supplement use after cancer diagnosis, and some may use supplements at high doses without consulting their healthcare providers. Methods: We evaluated the prevalence, dose, and reason of dietary supplement use among 3988 adult cancer survivors in the National Health and Nutrition Examination Survey (NHANES) 1999-2014 and compared that to 7770 individuals without a history of cancer who were matched cancer survivors by age, sex, and race/ethnicity. Findings: Compared to individuals without cancer, cancer survivors reported a higher prevalence of any dietary supplement use (69·9% vs. 63·4%), multivitamin/mineral supplement use (51·1% vs. 46·4%), and individual supplement use for each of the 26 vitamins and minerals being examined. Cancer survivors did not differ from non-cancer individuals for nutrient intake from foods but had higher levels of nutrient intake for five vitamins (vitamin A, retinol, vitamin D, niacin, folate) and five minerals (calcium, selenium, magnesium, zinc, and copper) from supplements than non-cancer individuals. While supplement use contributed to a lower percentage of cancer survivors with inadequate intake (< Estimated Average Requirement) for vitamins C, D, and E, it also increased the percentage of cancer survivors with excess intake (≥Tolerable Upper Intake Levels) for vitamin D, folate, vitamin B6, niacin, and selenium. Nearly half (48·5%) of the cancer survivors used dietary supplements on their own without consulting healthcare providers. Interpretation: Cancer survivors reported a higher prevalence and dose of dietary supplement use than the general population. The short-term and long-term health impact of dietary supplement use, especially high doses of supplement use among cancer survivors needs to be evaluated. Funding: This study was supported by NIH/ NIMHD 1R01MD011501 (FFZ). Declaration of Interest: The authors have no conflicts of interests to disclose. Ethical Approval: The NHANES study procedures were approved by the research ethics review board of NCHS.