Dietary Supplement Use among Adult Cancer Survivors in the United States

Background: Many cancer patients initiate dietary supplement use after cancer diagnosis. How dietary supplement use contributes to the total nutrient intake among cancer survivors as compared with individuals without cancer needs to be determined. Objectives: We aimed to evaluate nutrient intakes from dietary supplements among cancer survivors in relation to their total nutrient intake and compare those with individuals without cancer. Methods: We evaluated the prevalence, dose, and reason for using dietary supplements among 2772 adult cancer survivors and 31,310 individuals without cancer who participated in the NHANES 2003-2016. Results: Cancer survivors reported a higher prevalence of any (70.4% vs. 51.2%) and multivitamin/mineral (48.9% vs. 36.6%) supplement use and supplement use of 11 individual vitamins and 8 minerals than individuals without cancer. Overall, cancer survivors had significantly higher amounts of nutrient intake from supplements but lower nutrient intakes from foods for the majority of the nutrients. Compared with individuals without cancer, cancer survivors had a higher percentage of individuals with inadequate intake (total nutrient intake <Estimated Average Requirement or Adequate Intake) for folate, vitamin B-6, niacin, calcium, copper, and phosphorus, due to lower intakes of these nutrients from foods. Cancer survivors also had a higher proportion of individuals with excess intake (total nutrient intake >= Tolerable Upper Intake Level) for vitamin D, vitamin B-6, niacin, calcium, magnesium, and zinc, contributed by higher intakes of these nutrients from dietary supplements. Nearly half (46.1%) used dietary supplements on their own without consulting health care providers. Conclusions: Cancer survivors reported a higher prevalence and dose of dietary supplement use but lower amounts of nutrient intake from foods than individuals without cancer. The inadequate nutrient intake from foods and the short-term and long-term health impact of dietary supplement use, especially at high doses, need to be further evaluated among cancer survivors.