Dietary Supplement Use Is Associated with Select Serum Nutrient Biomarkers among Postmenopausal Women: Results from a Controlled Feeding Study

Abstract

Background: Dietary supplement use is common among older adults; however, the association between supplement use and corresponding nutrient biomarkers in this population is less well understood. Objectives: This study aimed to determine whether older women using dietary supplements had higher serum concentrations of corresponding biomarkers and whether those using multiple supplement sources of the nutrient had incrementally higher serum nutrient concentrations. Methods: Participants from the Women's Health Initiative enrolled in a 2-wk feeding study (n = 153). Women consumed an individualized menu and maintained intake of usual dietary supplements. Serum vitamin B12, lutein + zeaxanthin, and phospholipid fatty acids were measured at the end of the feeding period. Multiple linear regression of dietary supplement use, and participant characteristics on log-transformed serum biomarker concentrations was used to evaluate the association. One-way analysis of variance determined whether there were significant differences in mean serum biomarkers among participants based on the number of sources of a nutrient consumed via dietary supplement. Results: In multiple linear regression models (n = 152), users of vitamin B12 supplements had 58% higher geometric mean serum concentrations of vitamin B12 than nonusers (P < 0.001). Users of omega-3 fatty acid dietary supplements had geometric mean serum phospholipid docosahexaenoic acid + eicosapentaenoic acid that were 38%–46% higher than nonusers (P < 0.0001). In contrast, use of lutein + zeaxanthin-containing supplements was not associated with serum lutein + zeaxanthin (P = 0.72). Users of 2 sources of vitamin B12 and lutein + zeaxanthin-containing dietary supplements had higher corresponding serum biomarkers than users of only a multivitamin and users of neither (P < 0.0001). Conclusions: The use of vitamin B12 and omega-3 fatty acid supplements were associated with higher serum biomarkers, respectively. Dietary supplements containing lutein + zeaxanthin may not increase serum biomarkers among postmenopausal women. Trial registration number: This trial was registered at clinicaltrials.gov as NCT00000611.