| Contents Notes |
Bioavailability of selenium (Se) in processed tuna and wheat products was studied in humans and rats. The protein source of the rat diets was torula yeast with Se supplied by either raw, precooked or canned tuna, or whole wheat flour, bread or bran. Sodium selenite was used as a control. Each Se source was fed at three levels; 0.05, 0.10 and 0.15 ppm. Using increase in glutathione peroxidase (GSH-Px) activity in various tissues of rats as an indicator of bioavailabiiity, no difference was seen among the three tuna products or among the three wheat products tested. However, significantly lower GSH-Px activity was found in the combined tuna groups as co(S1(Bpared to the combined wheat groups, suggesting that the Se an wheat was more available than that in tuna. Se concentration m four rat tissues (Liver, Kidney, Whole blood and muscle) was also measured. A significant increase in the liver Se content of rats fed canned tuna over those fed raw or precooked tuna was observed. Since this did not correspond with an increase in GSH-Px activity it was concluded that it did not represent increased bioavaiiability of canned tuna. In the human experiment, eight young men ate controlled diets where the Se was supplied by either whole wheat bread or canned tuna for two week periods. The Se content of the tuna diet was 331.5 ug/day and the bread diet was 354 ug/ day. No difference was observed in whole blood GSH-Px or Se due to the tuna or bread diets but this may be due to the short time period. No significant difference in excretion of Se was observed in the balance study. On the tuna diet, the subjects excreted 72.7% of the Se consumed and on the bread diet they excreted 70.4%. |
