p. 93
Carnosine is an avid chelator of metal ions (Baran, 2000). Complexes with calcium, copper, and zinc ions have been described (Trombley et al., 2000).
p. 120
It is suggested that the carnosine–zinc complex both stimulates bone formation by osteoblasts and decreases bone resorption by the osteoclasts (Yamaguchi, 1995; Yamaguchi and Kishi, 1995a). The mechanisms involved remain obscure, but it appears that in cultured mouse marrow cells the carnosine–zinc complex inhibits osteoclast cell formation, when present at between 10 (- 6) and 10 (- 4) M, by inhibiting the action of transforming growth factor-b (Yamaguchi and Kishi, 1995a) and parathyroid hormone, possibly by interfering with calcium signaling (Yamaguchi and Kishi, 1995b). It is also possible that the zinc–carnosine complex enhances the anabolic effects of estrogen on osteoblasts (Yamaguchi and Matsui, 1997). It is clear from these observations that carnosine, when complexed with zinc, may have beneficial effects towards control of osteoporosis but many more studies, including double-blind trials in humans, are required before any unequivocal statement of its efficacy can be made.