Volume 90, Issue 1, July (2003), pp. 161-168 © The Author 2003
doi:10.1079/BJN2003887

Medline/PubMed Citation | Related Articles in PubMed | Download to Citation Matcher  

Adaptive responses in men fed low- and high-copper diets

Linda J. Harvey¹, Gosia Majsak-Newman¹, Jack R. Dainty¹, D. John Lewis², Nicola J. Langford², Helen M. Crews², Susan J. Fairweather-Tait^1
1Nutrition and Consumer Science Division, Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA, , UK
²Central Science Laboratory, Sand Hutton, York, YO41 1LZ, , UK

 (Received 11 March 2002–Revised 11 February 2003–Accepted 3 March 2003)

The study of Cu metabolism is hampered by a lack of sensitive and specific biomarkers of status and suitable isotopic labels, but limited information suggests that Cu homeostasis is maintained through changes in absorption and endogenous loss. The aim of the present study was to employ stable-isotope techniques to measure Cu absorption and endogenous losses in adult men adapted to low, moderate and high Cu-supplemented diets. Twelve healthy men, aged 20–59 years, were given diets containing 0·7, 1·6 and 6·0 mg Cu/d for 8 weeks, with at least 4 weeks intervening washout periods. After 6 weeks adaptation, apparent and true absorption of Cu were determined by measuring luminal loss and endogenous excretion of Cu following oral administration of 3 mg highly enriched ⁶⁵Cu stable-isotope label. Apparent and true absorption (41 and 48 % respectively) on the low-Cu diet were not significantly different from the high-Cu diet (45 and 48 % respectively). Endogenous losses were significantly reduced on the low- (0·45 mg/d; P<0·001) and medium- (0·81 mg/d; P=0·001) compared with the high-Cu diet (2·46 mg/d). No biochemical changes resulting from the dietary intervention were observed. Cu homeostasis was maintained over a wide range of intake and more rapidly at the lower intake, mainly through changes in endogenous excretion.

Keywords:
Copper, Fructose, Stable isotopes, Copper absorption, Copper endogenous losses

Abbreviations:
GPx, glutathione peroxidase, ICP–MS, inductively coupled plasma–mass spectrometry, IFR, Institute of Food Research, SOD, Cu,Zn-superoxide dismutase