Zinc absorption in healthy elderly humans and the effect of diet.

Absorption of a zinc stable isotope was measured on two consecutive occasions in nine young and eight elderly healthy men aged 24-40 and 70-83 y, respectively. A zinc stable-isotope label (0.8 mg 70Zn) was added to a test meal of either high or low zinc bioavailability, depending mainly on phytic acid content. Zinc absorption from the high-bioavailability test meal was not significantly different (P > 0.05) in the young (38.9 +/- 9.8%, mean +/- SD) and elderly (35.0 +/- 10.9%) subjects. Zinc absorption from the low-bioavailability test meal was 40% and 43% lower, at 23.4 +/- 10.2% and 19.8 +/- 6.1% in these young and elderly men, respectively. Again, no significant effect of age was found. These results show that aging does not lead to nutritionally relevant changes in zinc absorption and in the effect of dietary inhibitors on zinc absorption. Thus, zinc absorption ability seems to be preserved in healthy elderly people, at least until the age of 80 y.