Interaction of zinc and vitamin A in rats receiving a regional diet of Manaus, Amazonas, Brazil. Effect of supplementation with vitamin A, zinc and zinc and vitamin A

Yuyama, L.K.; Cozzolino, S.M.

Archivos Latinoamericanos de Nutricion 46(3): 216-220

1996


ISSN/ISBN: 0004-0622
PMID: 9429624
Document Number: 468303
13 female Wistar rats with 6 offspring each, were fed ad libitum on a casein-based diet deficient in vitamin A and zinc during lactation (depleted group). At the same time, 2 other female Wistar rats with 6 offspring each, were fed on complete casein-based diets (control group). After 25 days, 6 offspring from both groups were killed and plasma Zn levels and plasma and liver vitamin A levels were assessed. The remaining offspring from the depleted group were fed on a regional diet (RD) (Zn 2.2 mg% and vitamin A 25.8 micro g%) simulating that of people living in Manaus, Amazonia, Brazil who earn less than 2 minimum salaries, for 7 days to adapt to this diet. Six rats from this group were killed and the assays were repeated. Rats were then divided into 5 groups (n=8 per group) for 30 days and were fed on: the RD; the RD + vitamin A 94.2 micro g%; the RD + Zn 0.82 mg%; the RD + Zn 0.82 mg% + vitamin A 94.2 micro g%; or a standard laboratory diet (Zn 3.0 mg% and vitamin A 120 micro g%). During the depletion period, the plasma vitamin A and femur Zn levels were lower (P<0.05) in the depleted than in the control group. There were no differences in liver vitamin A levels between the depleted and control groups, suggesting vitamin A was not sufficiently mobilised from the liver. Femur Zn levels in rats fed on any of the RD supplemented diets were higher (P<0.05) than in rats fed on the unsupplemented RD, suggesting Zn in the RD is in an available form. There were no significant inter-group differences in the activity of alcohol dehydrogenase in testes, except that the activity of this enzyme was higher (P<0.05) in the RD + Zn group than in the other groups. Plasma vitamin A levels in the RD fed rats were not significantly different from any other group, except the RD + Zn and vitamin A group which had higher (P<0.05) plasma vitamin A levels than the other groups. Liver vitamin A levels were lower (P<0.05) in the RD group than in the RD + vitamin A, RD + Zn + vitamin A and control groups, but not the RD + Zn group. It is concluded that although the regional diet of Manaus did not meet the Zn RDA, the amount present was enough to utilize the available vitamin A, but that it may be appropriate to supplement the RD with vitamin A to maintain the hepatic reserves and with Zn, to maintain the normal plasma vitamin A levels.

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