Effect of beta-carotene supplementation and lactation on carotenoid metabolism and mitogenic T lymphocyte proliferation

Background: Information is lacking regarding the effects of beta-carotene s upplementation, early lactation, or both on circulating carotenoid concentr ations and T lymphocyte proliferation. Objectives: This study investigated the effects of short-term beta-carotene supplementation (30 mg/d for 28 d) during early lactation (days 4-32 postp artum) on circulating carotenoid concentrations and on the T lymphocyte pro liferative response to phytohemagglutinin. Design: Subjects aged 19-39 y were paired [lactating (4 d postpartum) and n onlactating (never pregnant, healthy women)] and randomly assigned to recei ve either beta-carotene or a placebo. During the study, subjects provided e ight 24-h food records for analysis with the NUTRITIONIST IV and US Departm ent of Agriculture carotenoid databases. Nonfasting blood samples were coll ected at baseline and at 28 d. Plasma analysis included quantification of a lpha-carotene, beta-carotene, lutein, lycopene, retinol, and alpha-tocopher ol, complete differential blood cell counts, and lymphocyte proliferative a ctivity. Results: beta-Carotene supplementation increased beta-carotene (P < 0.001) and alpha-carotene (P < 0.05) concentrations but did not affect lycopene co ncentrations significantly. Supplemented women showed significant decreases in plasma lutein (P < 0.03), as did lactating subjects (P < 0.02). Neither lactation nor beta-carotene supplementation affected the T lymphocyte prol iferative response to phytohemagglutinin. Conclusions: Our results suggest that beta-carotene supplementation as well as some events related to parturition, initiation of lactation, or both al ter circulating concentrations of lutein. beta-Carotene supplementation doe s not enhance T lymphocyte immune competence in healthy women.