A zinc tolerance test

A standardized oral zinc tolerance test for assessment of zinc absorption in dogs

Three oral zinc tolerance tests using increasing doses of elemental zinc (0.5, 0.75 and 1.0 mg/kg) given as zinc sulphate (ZnSO4.7H2O) were carried out in eight normal beagles. The zinc tolerance curves obtained were similar to those described in man, with the peak plasma zinc concentration occurring 2 h after dosing. There was a considerable variation between individual animals in the peak plasma zinc concentration achieved with each dose. This would appear to limit the value of a zinc tolerance test in assessing the efficiency of zinc absorption in individuals, although it may be of value in making comparisons between groups of dogs.

Fibre in enteral formulae: effects of sugar-beet versus soy fibre on zinc and folic acid absorption in human subjects

The present study was conducted to compare the effect of soypolysaccharide (Fibrem) and sugar-beet (Fibrex) on zinc and folic acid absorption when incorporated into enteral formulae. Following an overnight fast, 15 adults were challenged with an oral dose of zinc (60 mg) and folic acid (600 mug) given with enteral formula without fibre, or with 15g of dietary fibre from Fibrem or Fibrex. Serum concentrations of zinc and folic acid were measured at zero-time and at hourly intervals for up to 5h. Results showed that Fibrem caused a significant decrease in the concentrations of zinc and folic acid. However, Fibrex caused a slight increase in serum zinc concentration and a less pronounced decrease in serum folic acid concentration as compared to Fibrem. We conclude that for patients who are at risk of zinc or folic acid deficiency, the fibre source in enteral formulae should be selected carefully.

Bioavailability of orally administered zinc, using Taurizine

Zinc aspartate equivalent to 50 mg of elementary zinc, orally administered to seven normal healthy male volunteers in an enteric-coated tablet (Taurizine), gave no significantly increased plasma zinc levels, neither when this drug was taken in a fasting state nor during a lunch. The formulation of this tablet seems to obstruct the absorption of zinc.