Retention of selenium (75Se), Zinc (65Zn) and manganese (54Mn) in humans after intake of a labelled vitamin and mineral supplement.

: The whole body retention of 75Se, 65Zn, and 54Mn after intake of a labelled vitamin and mineral supplement was followed in 12 healthy volunteers. The supplement had a vitamin and mineral content according to recommended dietary allowances or the so-called "safe and adequate levels" for trace elements, including 15 mg of zinc as zinc citrate, 50 micrograms of selenium as sodium selenite and 2.5 mg of manganese as manganese sulphate. The supplement was taken either in the fasting state or together with a light meal. Retention day 14 was 48 +/- 6%, 33 +/- 6% and 5 +/- 2% (mean +/- SD) for selenium, zinc and manganese, respectively, when the supplement was taken fasting and 45 +/- 3%, 8 +/- 1% and 1.0 +/- 0.2% when it was taken with food. During day 1-14, 27%, 1% and less than 0.01% of the administered selenium, zinc and manganese radionuclides, respectively, were excreted in the urine. Based on the rate of turnover of the radionuclides and the urinary losses of 75Se, the absorption of selenium, zinc and manganese from the supplement was estimated to be 89 +/- 5%, 38 +/- 7%, 9 +/- 3% (mean +/- SD) in the fasting state and 87 +/- 4%, 10 +/- 2% and 2 +/- 1% with food. These results indicate that when a supplement is taken with food the minerals are absorbed and metabolized in the same way as are native minerals in food. When the supplement is taken in the fasting state, the absorption of zinc and manganese can be substantially higher.