Arch Environ Health. 1986 Sep-Oct; 41(5): 302-5.

Circadian rhythm of blood and urinary copper in presumably healthy subjects of vegetarian food habit.

Bhattacharya RD.

Circadian rhythm of blood and urinary copper has been studied in presumably healthy subjects of a particular ethnic group in India who are vegetarians. A definite 24-hr variation has been observed for both blood and urinary copper. The peak for blood copper was 1,500 hr and the lowest value was 0600 hr, with values of 0.185 mg/100 ml and 0.106 mg/100 ml respectively. The urinary peak and trough occurred at 0600 and 0300 hr, respectively. Remarkably higher 24-hr copper excretion values were noted (64.49 micrograms/day) with a range of 15-100 micrograms/day. The blood level of copper (0.134 mg/100 ml) remained within the range reported. One subject out of 25 deviated from the group with respect to circadian phasing and amplitude to urinary copper excretion.