Effects of paprika carotenoid supplementation on bone turnover in postmenopausal women: a randomized, double-blind, placebo-controlled, parallel-group comparison study

Background Paprika (Capsicum annuum L.) is a good source of carotenoids, including capsanthin, β-carotene, β-cryptoxanthin, and zeaxanthin. Several epidemiological studies have shown a beneficial association of intake of these carotenoids or their blood concentration with bone mineral density (BMD) and fracture risk. However, little information is available regarding the effect of intake of these carotenoids on bone metabolism in postmenopausal women. Objective The objective of the present study was to investigate the effects of paprika carotenoid extract (PCE) on bone turnover in healthy, postmenopausal women. Design We conducted a randomized, double-blind, placebo-controlled, parallel-group comparison study. One hundred participants were randomly assigned to PCE or placebo groups. Each group was given a 20 mg PCE (equivalent to 1.4 mg of carotenoids) a day or a placebo for 24 weeks. We measured bone resorption markers (tartrate-resistant acid phosphatase 5b [TRACP-5b] and serum type I collagen cross-linked N-telopeptide [sNTX]) at 12 and 24 weeks and bone formation markers (bone alkaline phosphatase and osteocalcin) at 24 weeks. Results The percentage decrease of TRACP-5b at 24 weeks was significantly higher for PCE than the placebo. There were no significant differences in sNTX or bone formation markers, although PCE decreased each marker compared with the placebo. Conclusion Our findings suggest that PCE supplementation suppresses bone resorption and contributes to maintaining bone quality in postmenopausal women.