The effect of low dietary copper on copper status and the copper-conta
ining enzyme lysyl oxidase was studied in young men. The study was div
ided into three dietary periods. During the first period, subjects wer
e fed 0.66 mg/day Cu for 24 days (marginal copper). The level of coppe
r was dropped to 0.38 mg/day for the next 42 days (low copper) and the
y were repleted with 2.49 mg/day Cu for next 24 days. Skin biopsies we
re taken at the beginning of the study and at the end of each dietary
period and lysyl oxidase was measured enzymatically. There was a 24% d
rop in activity when the dietary copper level was reduced from 0.66 to
0.38 mg/day. When the subjects were repleted with copper, there was a
significant increase in the activity of lysyl oxidase. The activity r
eached the level observed before the subjects were fed the restricted
copper diet. These data show that, in humans, lysyl oxidase activity d
eclines when dietary copper intake is inadequate and suggests that the
cross-linking of collagen may be modulated by dietary copper. Lysyl o
xidase in healthy young men can serve as a useful indicator of copper
status. (C) Elsevier Science Inc. 1997.