Zinc in the food chain - its biological importance. Part Six: Excretion, balance and normative requierement of zinc in man

摘要

People with mixed diet excrete 10% of the zinc intake renally and 90% faecally. For omnivorous people, renal zinc excretion of 400 to 800 μg Zn/day is normal, whereas ovolactovegetarians excrete 300 to 500 μg Zn/day renally. Breast-feeding mothers excrete 5% (7.8 mg Zn/day) of their zinc intake renally, 17% with the milk, and 78% faecally. (The daily renal zinc excretion amounts to 450-500 μg Zn/day). The apparent zinc absorption rate of omnivores varied between 3 and 4%, that of vegetarians between 0.5 and 2.7%. The bioavailability of zinc in vegetarian diets is low. Most of the absorbed zinc is excreted into the intestine through bile, pancreas and gut secretions. The normative zinc requirement of women is < 6.0 mg/day, and of men, < 8.0 mg/day. The clinical requirement of zinc could be 3 and 4 mg Zn/day, respectively.