The influence of body composition, gonadal steroid status and gender on serum carotenoids and retino

The relationships of serum beta-carotene, lutein, zeaxanthin and retinol concentrations with body composition, serum estradiol concentrations, phase of menstrual cycle, use of oral contraceptive agents (OCA's) and gender were examined in 55 subjects taking SO mg supplements of beta-carotene daily for 28 days. Serum samples were collected from all subjects prior to supplementation, 8 hours following a single dose and on day 28 of supplementation. Serum carotenoids and retinol were measured by HPLC and serum estradiol and progesterone were measured by RIA. Baseline serum retinol concentrations were significantly higher (p $<$.01) in females using OCA's than in females not using OCA's. Baseline serum retinol concentrations were also significantly higher (p $<$.005) in males than in females not using OCA's, with the same body composition. Baseline serum beta-carotene concentrations were negatively correlated to percent body fat (r = $-$.5471; p $<$.01) and total body fat (r = $-$.5477; p $<$.01) in females. All groups had significantly higher (p $<$.05) serum beta-carotene concentrations at day-28 compared to initial concentrations. Also, all groups, except the low-body-fat groups, had significantly higher (p $<$.05) serum beta-carotene concentrations at 8-hours following a single dose compared to initial concentrations. These findings identify that the impact of personal characteristics on serum carotenoid and retinol concentrations is minimized when the individual is challenged with high doses of beta-carotene either acutely or chronically.