Selenium balance in young men during selenium depletion and repletion.

Selenium balance was determined in six young men fed for 45 days a formula depletion diet (33 to 36 micrograms Se/day) then fed for 25 days a repletion of diet (depletion diet plus 200 micrograms Se/day as high-Se wheat or wheat plus tuna fish). After 12 days of adaptation, Se balance during depletion was rather constant at -21 micrograms/day and Se losses in urine and feces were 54 micrograms/day. During repletion, Se balance was +64 micrograms/day for the first 12 days and +25 micrograms/day thereafter and the subjects regained all the Se lost during depletion. If the gastrointestinal absorption of the food Se in North Americans and New Zealanders is similar (80%), young North American men need a dietary Se intake of about 70 micrograms/day to replace losses and maintain body stores.