Determination of various nutrients and toxic elements in different Brazilian regional diets by neutron activation analysis.

The concentration of 19 elements (As, Br, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Rb, Sb, Sc, Se and Zn) was evaluated in some diets taken from different regions of Brazil by Instrumental and Radiochemical Neutron Activation Analysis. Several populations with different socio-economic living conditions and inhabiting in different regions of Brazil were studied in order to estimate and to detect the variability of the mineral and toxic element content among Brazilian populational groups. The data obtained showed a significant difference between the contents of these elements in the diets from the regions studied. The general conclusions from the data obtained in this study were: 1) regarding the daily amounts of essential elements (Ca, Cl, Co, Fe, Mn, Na, K, Fe, Se and Zn), the Santa Catarina 2 diet showed the closest values when compared to the recommended values of RDA (Recommended Dietary Allowance) and/or WHO (World Health Organization). The Santa Catarina 1(low income groups) showed the lowest when compared to the same values. 2) The intake of toxic elements (As, Br, Cd, Hg, Sb) among the diets does not seem to be a major problem when compared to PTWI (Provisional Tolerable Weekly Intake, WHO), except for Hg intakes in regions near gold mining activities, like Manaus and Mato Grosso, where the values found were near the upper limit set by WHO.

[Effect of supplementation with peach palm as source of vitamin A: study with rats]. / Efeito da suplementação com pupunha como fonte de vitamina A em dieta: estudo em ratos.

The effect of supplementation with peach palm (Bactris gasipaes H.B.K.), as an alternative source of vit. A, in the regional diet of Manaus, AM, Brazil, in which the pulp was cooked and transformed into flour, was studied. The biological trial involved rats which were depleted in zinc and vitamin A, followed by repletion using the regional diet (RD), RD plus peach palm and RD plus vitamin A. The parameters used to determine the utilization of vitamin A were the vitamin A concentrations in the liver and plasma, and the growth of the animals. The diet was prepared according to the data of Shrimpton and Giugliano for families earning less than two legal minimum salaries. Adult post-partum rats were used, with six male pups each, which received a diet based on casein washed with 1% EDTA, without the addition of zinc or vitamin A for a period of 25 days, for the purpose of obtaining newly-weaned animals which were deficient in Zn and Vit.A. A control group received a diet also based on casein washed with 1% EDTA, but with all the nutrients in the quantities suggested by the Committee on Laboratory Animal Diets. The repletion period of the newly-weaned rats was of 30 days and the experimental design was entirely randomized with four groups of eight rats each. The diet supplementation followed the recommendations of the Committee on Laboratory Animal Diets. At the end of the experiment, it was observed that rats which consumed the diet based on the regional diet of Manaus supplemented with either peach palm or vitamin A showed a significantly greater concentration of vitamin A in the liver, 43.3 +/- 6.5 micrograms/g, 42.0 +/- 4.3 micrograms/g, respectively in relation to the regional diet, 5.5 +/- 1.1 micrograms/g (p < 0.05). The amount of zinc present in the regional diet, 10.7 mg per day, was bioavailable as determined by the concentration of zinc in the femurs. The results suggest that the regional diet of Manaus needs to be supplemented with vitamin A to maintain the hepatic reserves, and that such supplementation can be accomplished with peach palm, an abundant local commodity.

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.

The interaction of zinc and vitamin A in rats receiving a regional diet of Manaus, supplemented with vitamin A, zinc and zinc and vitamin A was studied. The regional diet was elaborated according to data of Shrimpton and Giugliano (6), for families receiving less than two minimum salaries. The biological test to study the interaction was based on the depletion of zinc and vitamin A in rats in the period of lactation, and a period of repletion where supplements of zinc (0.82 mg%) and vitamin A (94.2 micrograms %) were given, either separately or together, according to the recommendations of the Committee on Laboratory Animal Diets (7). From the results, it was concluded that there was an interaction of these nutrients in terms of mobilization of hepatic vitamin A. Although the regional diet of Manaus did not meet the zinc RDA, the amount present was enough to utilize the available vitamin A. Although the amount of zinc present in the diet, as determined by parameters of bioavilability, such as growth, concentration in organs and zinc-dependent enzymes, was adequately used by the animals, probably due to promoting factors in the diet. The Manaus regional diet needs to be supplemented with vitamin A in order to maintain the hepatic reserves, and with zinc, to maintain the normal levels of vitamin A in plasma.

[Interaction of vitamin A and zinc in lactating rats. Experimental deficiency model]. / Interação de zinco e vitamina A em ratos na lactação. Modelo de deficiência experimental.

An experimental deficiency model of vitamin A and zinc in lactating rats was developed. The experimental design consisted in a depletion period of 4 weeks immediately after birth where test group animal received a casein based feed, deficient in zinc and vitamin A, and a control feed according to the recommendations of the Committee on Laboratory Animal Diets. Female Rathus norvergicus, var albinus (Rodentia, Mammalia) with 6 young males each were used. These came from the Biotério of the Faculdade de Ciências, Farmacêuticas of USP. At the end of the depletion period it was found that the weight of the males control group (109.1 g +/- 3.9 g) was significantly greater than that of the test group (40.8 g +/- 6.7 g). The same was true for the concentration of zinc in the femurs of these animals, in the control group the concentration was significantly greater (115.7 micrograms/g +/- 5.4 micrograms/g) than in the test group (35.5 micrograms/g +/- 3.3 micrograms). The concentration of vitamin A in the plasma of the control group (31.5 micrograms/dL +/- 2.5 micrograms/dL) also was significantly greater than the test group animals (8.9 micrograms/dL +/- 3.4 micrograms/dL). The concentration of hepatic vitamin A was similar for both groups. We can conclude that there was interaction of zinc and vitamin A, by liver and depletion in zinc. Although the plasmatic concentration of vitamin A indicates a depletion, this cannot be considered as total because of the hepatic reserves.