ZINC-ABSORPTION IN ADULT HUMANS - THE EFFECT OF PROTEIN-SOURCES ADDEDTO LIQUID TEST MEALS

The influence of different protein sources on Zn absorption was evalua ted in healthy adults by radioisotopic labelling of single meals, foll owed by whole-body retention measurements 14 d after intake, Semi-synt hetic liquid diets were used for the evaluation of different animal-pr otein sources and dephytinized soyabean-protein isolate (<0.01g phytic acid/kg), Zn absorption was measured in the same subjects from identi cal test meals containing no added protein, No statistically significa nt differences were found in the Zn absorption from test meals contain ing bovine whey, casein or egg albumen when compared with test meals w ithout added protein, Bovine serum albumin (BSA) and soyabean-protein isolate (<0.01 g phytic acid/kg) significantly reduced the mean absorp tion of Zn from 45-49 % (no added protein) to 38.0 (so 10.9) (BSA, P < 0.05) and 33.9 (so 12.6)% (soyabean-protein isolate < 0.01 g phytic a cid/kg, P < 0.01), These results demonstrate that Zn absorption is inh ibited by certain protein sources, such as BSA and dephytinized soyabe an-protein isolate, while other proteins have little or no effect.