Effect of dietary copper intakes on biochemical markers of bone metabolismin healthy adult males

Objective: To investigate the effects of changing from a medium (1.6 mg Cu/ d) to a low (0.7 mg Cu/d) or a high (6.0 mg/d) Cu intake on biochemical ind ices of bone turnover in healthy adult males. Design: A longitudinal intervention trial. Setting: The study was conducted at the institute of Food Research, Norwich , UK. Subjects: Eleven healthy adult males aged 20-59 y were recruited from Norwi ch Research Park. Intervention: Subjects were given medium (1.6 mg/d), low (0.7 mg/d) and hig h (6.0 mg/d) intakes of Cu, in that order, over consecutive 8 week periods with a minimum of 4 week washout periods. On the last d of each dietary per iod fasting first void urine and blood were collected. Results: Serum caeruloplasmin or Cu (indices of Cu status), serum osteocalc in (biomarker of bone formation), urinary creatinine (Cr) were unaffected b y dietary Cu intake. Urinary Pyr/Cr and Dpyr/Cr (biomarkers of bone resorpt ion) were significantly increased (P < 0.05) (by 30% and 25% respectively), when subjects were switched from the medium to the low Cu diet and were si gnificantly decreased (P < 0.05) (by 30% and 22% respectively), when subjec ts were switched from the low to the high Cu diet. Conclusion: The findings of the present study could have implications for b one health in individuals with marginal Cu intakes. Thus, further studies a re warranted to better define the relationship of marginal Cu intakes to bo ne health.