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Previous issue date: 2015-07-14 === As vitaminas A e E s?o nutrientes que possuem natureza lipof?lica e atuam em
v?rios processos biol?gicos importantes, como a imunidade, reprodu??o,
crescimento e desenvolvimento. Estas vitaminas s?o essenciais na fase inicial da
vida e devem ser transferidas adequadamente da m?e para o filho durante a
gesta??o e a lacta??o. A suplementa??o materna com vitamina A ? uma das
estrat?gias de controle de sua defici?ncia no grupo materno-infantil, entretanto,
estudos com animais evidenciaram que a suplementa??o com altas doses de
vitamina A reduziu os n?veis de alfa-tocoferol (vitamina E) no soro e no leite. Assim,
o objetivo deste trabalho foi avaliar a influ?ncia da suplementa??o materna com
vitamina A sobre a concentra??o de retinol e alfa-tocoferol nos leites colostro e
maduro de lactantes. Pu?rperas a termo e saud?veis foram aleatoriamente
distribu?das nos grupos controle (n = 44) e suplementado (n = 44). Amostras de
sangue e leite colostro foram coletadas no p?s-parto imediato e uma amostra de
leite maduro foi coletada ap?s 30 dias. O grupo suplementado recebeu uma
suplementa??o com palmitato de retinila (200.000 UI), imediatamente ap?s a
primeira coleta de colostro. O retinol e o alfa-tocoferol das amostras biol?gicas foram
analisados por Cromatografia L?quida de Alta Efici?ncia (CLAE). Valores s?ricos
abaixo de 20 ?g/dL para a vitamina A e 516 ?g/dL para a vitamina E foram
indicativos de defici?ncia. As concentra??es de retinol e alfa-tocoferol no soro das
lactantes foram 46,4 ? 15,9 ?g/ dL e 1.023,6 ? 380,4 ?g/ dL, respectivamente, sendo
consideradas adequadas. No grupo suplementado, verificou-se um aumento
significativo dos n?veis de retinol no leite colostro, 24 horas ap?s interven??o
(p<0,001), entretanto, n?o foi observada diferen?a estat?stica entre a concentra??o
de retinol no leite maduro dos grupos avaliados (p>0,05). Al?m disso, ap?s a
suplementa??o materna com vitamina A, houve uma redu??o significativa na
concentra??o de alfa-tocoferol no leite colostro (p<0,05), que correspondeu a um
decl?nio de 16,4% dos n?veis de vitamina E. Por outro lado, a administra??o do
suplemento n?o influenciou os n?veis de alfa-tocoferol no leite maduro (p>0,05).
Diante disso, conclui-se que a suplementa??o materna com altas doses de vitamina
A aumentou os n?veis desse micronutriente no leite colostro, por?m, reduziu a
biodisponibilidade do alfa-tocoferol, o que pode trazer preju?zos ? sa?de do neonato,
que possui reservas limitadas de vitamina E ao nascimento. === Vitamins A and E are lipophilic nutrients that act in many important biological
processes, such as immunity, reproduction, growth, and development. These
vitamins are essential during the initial phase of life and should be properly
transferred from mother to child during pregnancy and lactation. Maternal
supplementation with vitamin A is one of the strategies for controlling its deficiency in
the mother-child dyad, but studies with animals showed that supplementation with
high doses of vitamin A reduces the levels of alpha-tocopherol (vitamin E) in the
mother?s serum and milk. Hence, the objective of this study was to assess the
influence of maternal supplementation with vitamin A on the concentration of retinol
and alpha-tocopherol in colostrum and mature milk. Healthy puerperal women with
term deliveries were randomly distributed into a control group (n=44) and a
supplemented group (n=44). Blood and colostrum samples were collected
immediately after delivery, and mature blood samples were collected 30 days later.
The supplemented group received 200,000 IU of retinyl palmitate immediately after
the first colostrum collection. The retinol and alpha-tocopherol levels in the biological
samples were determined by high-performance liquid chromatography (HPLC).
Serum vitamin A levels below 20 ?g/dL and serum vitamin E levels below 516 ?g/dL
indicated deficiency. The retinol and alpha-tocopherol levels in the maternal serum
were considered adequate at 46.4 ? 15.9 ?g/ dL and 1,023.6 ? 380.4 ?g/ dL,
respectively. The colostrum retinol levels of the supplemented group increased
significantly 24 hours after the intervention (p<0.001). However, the retinol levels in
the mature milk of both groups did not differ (p>0.05). Moreover, after maternal
supplementation with vitamin A, colostrum alpha-tocopherol level decreased by
16.4%, a significant reduction (p<0.05). However, vitamin A supplementation did not
affect the alpha-tocopherol level of mature milk (p>0.05). In conclusion, maternal
supplementation with high doses of vitamin A increased the colostrum level of this
nutrient but reduced the bioavailability of alpha-tocopherol, which may harm the
newborn?s health since newborns have limited vitamin E reserves.
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