Dietary supplement use within a multiethnic population as measured by a unique inventory method

Abstract

Use of dietary supplements is widespread, yet intakes from supplements are difficult to quantify. The Supplement Reporting study utilized a unique inventory method to quantify dietary supplement use across 1 year in a sample of 397 supplement users. Interviewers visited participants' homes in 2005-2006 to record supplement purchases and the number of pills in each supplement bottle every 3 months. Total use for the year was calculated from these inventories. Participants in this observational study were older adults (average age 68 years) from the Multiethnic Cohort in Hawaii and Los Angeles, CA, with approximately equal representation of men and women and six ethnic groups (white, Japanese American, Hawaiian, African American, Latinos born in the United States, and Latinos born elsewhere). The most commonly used supplement type was one-a-day multivitamins/minerals, which were taken at least once during the year by 83% of men and 73% of women. Other common supplements were vitamin C, fish oil, vitamin E, and bone or joint supplements. Participants used a median of seven (women) and five and a half (men) different supplements during the year. There were few differences in supplement use across ethnic groups for men, but use tended to be highest for white and Japanese-American women. Use of nonvitamin/nonmineral supplements was common among these older adults, sometimes at high doses. When assessing intakes, supplement use should be correctly quantified because users tend to take many different supplements and nutrient intakes from supplements can be substantial. The inventory method may help improve the measurement of supplement use.