Micronutrientes na gestação e lactação

Dietary Lipid Intake Influences the Alpha-tocopherol Levels in Human Milk

OBJECTIVE

Dietary lipid intake is associated with serum alpha-tocopherol levels; however, its impact on human milk is unknown. The objective of this study was to evaluate the relationship between maternal intake of vitamin E, lipids, and fatty acids and the concentration of alpha-tocopherol in human milk.

METHODS

We conducted a longitudinal observational study, including 143 lactating women on 7, 30, and 90 days postpartum. Dietary intake was collected using 24-hour recall. On day 90, a human milk sample was collected and analyzed for alpha-tocopherol concentration. The prevalence of inadequate vitamin E intake was determined by the Estimated Average Requirement (16 mg/day), and the alpha-tocopherol concentration was analyzed by high-performance liquid chromatography.

RESULTS

Dietary intake of vitamin E was associated with the intake of lipids (r = 0.237, P = 0.004) and fatty acids (P < 0.05), and 100% of the participants had inadequate vitamin intake. Mean alpha-tocopherol concentration in the human milk samples was 7.11 (standard deviation 3.95) μmol/L and was correlated with lipid (r = 0.201, P = 0.042) and polyunsaturated fatty acid intake (r = 0.235, P = 0.017). Higher vitamin E levels were found in participants with the highest quartile of polyunsaturated fatty acid intake.

CONCLUSIONS

Alpha-tocopherol concentration was associated with the dietary intake of lipids and fatty acids, demonstrating that its bioavailability is associated with fats in the mammary gland. These results suggest development of appropriate strategies to increase the levels of vitamin E in breast milk that may help to prevent and treat vitamin E deficiency.

[Nutritional and sociodemographic characteristics of nursing mothers: a systematic review]

A systematic review of nutritional and sociodemographic characteristics of nursing mothers, using the published literature from 2004 to 2014 in the Biblioteca Virtual de Saúde and Medline databases. Using the following key words, 561 articles were identified: "Human Milk" and "Milk Banks"; keywords: "Profile," "Nutritional," "Milk Donor," "Nursing Mother" and "Nursing Mothers"; available abstracts; date and language. From these, 84.1% were excluded for not dealing with the established subject, 1.8% for being a review and 7.5% for the unavailability of abstracts for study. Thirty-seven articles were selected, of which 18.9% analyzed the profile of the HM donor. Of the total, 89.2% reported age, the majority between 20 and 30 years of age. The level of schooling was mentioned in 32.4% ranging from elementary school and higher education. With respect to income, a higher prevalence of low socioeconomic status was observed. About the nutritional status, 45.9% of the studies measured the body mass index and 29.4% reported the predominance of excess weight. There were deficiencies, particularly of vitamin A, with frequencies between 9% and 26%. A majority of young adult mothers, varied schooling, low income and nutritional deficiencies were noted, demanding interventions to improve health and increase HM donations.

Effect of maternal supplementation with vitamin E on the concentration of α-tocopherol in colostrum

OBJECTIVE

To evaluate the effect of maternal supplementation with vitamin E on the concentration of α-tocopherol in colostrum and its supply to the newborn.

METHOD

This randomized clinical trial enrolled 99 healthy adult pregnant women; of these, 39 were assigned to the control group and 60 to the supplemented group. After an overnight fast, 5mL of blood and 2mL of colostrum were collected. After the first sampling (0h milk), the supplemented group received 400IU of supplementary vitamin E. Another 2mL milk aliquot was collected in both groups 24h after supplementation (24h milk). The samples were analyzed by high-performance liquid chromatography. The α-tocopherol content provided by colostrum was calculated by considering a daily intake of 396mL of milk and comparing the resulting value to the recommended daily intake for infants aged 0-6 months (4mg/day).

RESULTS

The initial mean concentration of α-tocopherol in colostrum was 1509.3±793.7μg/dL in the control group and 1452.9±808.6μg/dL in the supplemented group. After 24h, the mean α-tocopherol concentration was 1650.6±968.7μg/dL in the control group (p>0.05) and 2346.9±1203.2μg/dL in the supplemented group (p<0.001), increasing the vitamin E supply to the newborn to 9.3mg/day. Initially, 18 women in the supplemented group provided colostrum α-tocopherol contents below 4mg/day; after supplementation only six continued to provide less than the recommended amount.

CONCLUSION

Maternal vitamin E supplementation increases the supply of the vitamin to the infant by providing more than twice the Recommended Daily Intake.

Maternal supplementation with a megadose of vitamin A reduces colostrum level of α-tocopherol: a randomised controlled trial

BACKGROUND

Maternal supplementation with vitamin A is one of the strategies for controlling its deficiency in the mother-child dyad, although studies with animals showed that supplementation with high doses of vitamin A reduces the levels of α-tocopherol (vitamin E) in the mother's serum and milk. The objective of the present study was to assess the influence of maternal supplementation with vitamin A on the concentration of retinol and α-tocopherol in human milk.

METHODS

Healthy puerperal women were randomly distributed into a control group (n = 44) and a supplemented group (n = 44). Blood and colostrum samples were collected after delivery, and mature milk samples were collected 30 days later. The supplemented group received 200 000 IU of retinyl palmitate after the first colostrum collection. The retinol and α-tocopherol levels in the samples were determined by high-performance liquid chromatography.

RESULTS

The mean (SD) retinol and α-tocopherol levels in the maternal serum were considered adequate at 46.4 (15.9) and 1023.6 (380.4) μg dL(-1) , respectively. The colostrum retinol levels of the supplemented group increased significantly 24 h 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, the colostrum α-tocopherol level decreased by 16.4%, which is a significant reduction (P < 0.05). However, vitamin A supplementation did not affect the α-tocopherol level of mature milk (P > 0.05).

CONCLUSIONS

Maternal supplementation with high doses of vitamin A increased the colostrum level of this nutrient but reduced the bioavailability of α-tocopherol, which may harm the newborn's health because newborns have limited vitamin E reserves.

Oxidative Profile and δ-Aminolevulinate Dehydratase Activity in Healthy Pregnant Women with Iron Supplementation

An oxidative burst occurs during pregnancy due to the large consumption of oxygen in the tissues and an increase in metabolic demands in response to maternal physiological changes and fetal growth. This study aimed to determine the oxidative profile and activity of δ-aminolevulinate dehydratase (δ-ALA-D) in pregnant women who received iron supplementation. Oxidative stress parameters were evaluated in 25 pregnant women with iron supplementation, 25 pregnant women without supplementation and 25 non-pregnant women. The following oxidative stress parameters were evaluated: thiobarbituric acid reactive substances (TBARS), protein thiol groups (P-SH), non-protein thiol levels (NP-SH), vitamin C levels, catalase and δ-ALA-D activity. Markers of oxidative stress and cell damage, such as TBARS in plasma were significantly higher in pregnant women without supplementation. Levels of P-SH, NP-SH and δ-ALA-D activity were significantly lower in pregnant women without supplementation compared to non-pregnant and pregnant women with supplementation, while vitamin C levels were significantly lower in pregnant women without supplementation when compared to non-pregnant women. The increase in the generation of oxidative species and decrease of antioxidants suggest the loss of physiological oxidative balance during normal pregnancy, which was not observed in pregnant women with iron supplementation, suggesting a protective effect of iron against oxidative damage.

Isolated and combined prevalence of anemia, vitamin A deficiency and zinc deficiency in preschool children 12-72 months for the government of Paraíba

OBJECTIVE: To estimate the isolated and combined prevalence of anemia, vitamin A deficiency and zinc deficiency in pre-school children, as well as the distribution of isolated deficiencies according to gender, age and prior supplementation with vitamin A. METHODS: Cross-sectional study with pre-school children in the state of Paraíba, Brazil. Analysis of the average concentrations of hemoglobin, serum retinol and serum zinc, according to gender, age and previous vitamin A supplementation of children were carried out as well as the risk of simultaneous occurrence of micronutrient deficiencies in the presence of these deficiencies. RESULTS: The prevalence of anemia, vitamin A deficiency and zinc deficiency were 15.4%, 23.3% and 13.8%, respectively. The anemia was significantly associated with age (p<0.01). Children previously supplemented by vitamin A had higher serum retinol concentrations than children without supplements, an effect that was not observed for concentrations of hemoglobin or serum zinc. The prevalence of anemia associated with vitamin A deficiency was 5.8%, with the chance of vitamin A deficiency and anemia coexist 2.21 times (95%CI=1.03-4.84) higher in the case of vitamin A deficiency or anemia rather than in the absence of these conditions. CONCLUSION: The high prevalence of micronutrient deficiencies which are important in child growth, as well as the coexistence of nutritional deficiencies, point out the need to strengthen nutrition intervention strategies that consider this issue.

Evidências do impacto da suplementação múltipla com micronutrientes no crescimento de pré-escolares: revisão sistemática

Objetivos: agregar evidências sobre o efeito da suplementação múltipla com micronutrientes no crescimento de crianças pré-escolares, com ênfase nos efeitos combinados ou isolados do zinco, ferro e vitamina A. Métodos: foi realizada uma busca por ensaios clínicos aleatorizados e artigos de revisão sistemática com metanálise na base de dados PubMed. Foram selecionados artigos publicados entre 1995 e maio de 2013, considerando a combinação dos descritores (child, preschool OR infant) AND (growth) AND (zinc AND iron AND vitamin A) OR (zinc AND iron) OR (zinc AND vitamin A) OR (iron AND vitamin A). Resultados: foram selecionados 33 artigos para a presente revisão, 29 do tipo ensaio clínico e quatro de revisão sistemática com metanálise. A administração de suplementos nutricionais contendo combinações de zinco, ferro e vitamina A pode aumentar o potencial de crescimento das crianças, sendo mais evidente o efeito quando comparada a suplementação com múltiplos micronutrientes vs placebo ou dieta habitual, e com os esquemas de suplementação dupla e única. A combinação de zinco e vitamina A é a melhor opção de suplementação dupla. O efeito da suplementação tripla em relação às outras opções (placebo, única, dupla, múltipla), bem como os possíveis efeitos diferenciados da suplementação segundo a condição nutricional e/ou idade das crianças, ainda precisam de investigação mais aprofundada para orientar as estratégias de prevenção. Conclusões: a suplementação múltipla com micronutrientes tem efeitos positivos no crescimento linear que dependem do esquema de suplementação adotado.

Avaliação de desempenho das concentrações capilares de zinco como método diagnóstico da deficiência de zinco: um estudo comparativo com as concentrações séricas de zinco

OBJETIVO: Examinar o poder diagnóstico de deficiência de zinco das concentrações capilares desse mineral por meio da comparação com as concentrações séricas. MÉTODOS: Estudo transversal desenvolvido com 170 crianças na faixa etária dos 12 aos 72 meses. A análise da Curva Característica de Operação do Receptor foi utilizada para identificar a sensibilidade e a especificidade do melhor ponto de corte para o diagnóstico da deficiência de zinco no cabelo. Verificou-se ainda a significância estatística da área sob a curva. RESULTADOS:O ponto de corte apontado como ótimo para o zinco no cabelo foi de 292,52ppm (sensibilidade de 55,6% e especificidade de 60,8%), com uma área sob a curva de 0,549, sem significância estatística. CONCLUSÃO: O diagnóstico da deficiência de zinco pelas concentrações capilares desse elemento, em comparação às concentrações séricas de zinco, mostra baixa sensibilidade e ponto de corte ideal superior ao sugerido. Permanece, ainda, a necessidade de novos estudos que possibilitem a obtenção de indicadores bioquímicos mais sensíveis e específicos para o diagnóstico da deficiência de zinco na população, sob tudo sem importantes limitações técnicas.

Deficiência de micronutrientes e crescimento linear: revisão sistemática de estudos observacionais

O objetivo do artigo é avaliar a associação das deficiências de ferro, vitamina A e zinco com o déficit de crescimento linear. Revisão sistemática nas bases de dados eletrônicas PubMed, LILACS e SciELO. Foram selecionados artigos publicados entre janeiro de 1995 e março de 2010, considerando os descritores: (growth OR nutritional status) AND (child, preschool OR infant) AND (zinc AND iron AND vitamin A) OR (zinc AND iron) OR (zinc AND vitamin A) OR (iron AND vitamin A). Foram revisados 14 estudos de delineamento observacional. Dos estudos tipo coorte (dois), um indicou associação estatística entre o estado nutricional de ferro e o déficit de estatura; o outro apontou associação estatística entre as concentrações de ferritina sérica e o ganho de estatura. Dez estudos transversais investigaram a associação estatística entre as deficiências de micronutrientes e o déficit de estatura, resultando três deles na associação para o ferro, dois para a vitamina A e nenhum para o zinco. O esclarecimento sobre a associação entre o déficit de estatura e as deficiências de ferro, vitamina A e zinco dificulta-se por fatores de caráter biológico e relacionados à magnitude das deficiências, o que sugere a importância da padronização metodológica dos estudos.

Índices antropométricos e retinolemia em crianças menores de cinco anos do e Estado da Paraíba

OBJETIVO: Avaliar a relação entre os índices antropométricos e os níveis de retinol sérico em crianças menores de cinco anos do Estado da Paraíba. MÉTODOS: Estudo de corte transversal, de base populacional, envolvendo 1 205 crianças. O estado nutricional de vitamina A foi avaliado pelas concentrações séricas de retinol. O estado nutricional antropométrico foi avaliado utilizando-se os índices peso/altura e altura/idade. RESULTADOS: Crianças na faixa etária de 6 a 12 meses com deficit de altura apresentaram concentrações de retinol sérico significantemente inferiores quando comparadas às crianças sem deficit de altura (p=0,02). CONCLUSÃO: A associação observada entre deficit de altura e menores níveis de retinol sérico em crianças de menor faixa etária mostra a maior vulnerabilidade desse grupo para sofrer deficits vitamínicos e de crescimento.

Estado nutricional relativo ao zinco de crianças que frequentam creches do estado da Paraíba

OBJETIVO: Avaliar o estado nutricional relativo ao zinco de crianças assistidas em creches do Estado da Paraíba. MÉTODOS: O estado nutricional relativo ao zinco de 235 crianças pré-escolares foi avaliado através de sua concentração no soro, da ingestão dietética de zinco e da estatura para idade, como recomendado pelo International Zinc Consultative Group. As concentrações séricas de zinco foram determinadas por espectrofotometria de absorção atômica de chama, considerando deficiência de zinco valores <65µmol/L. O consumo alimentar foi registrado mediante o recordatório de 24 horas, considerando a alimentação da criança no dia anterior e o consumo de alimentos na creche, e foi analisada a inadequação dietética de zinco de acordo com as necessidades médias estimadas de zinco segundo etapa da vida e tipo de dieta estabelecido pelo International Zinc Consultative Group. Adotou-se o Padrão de Crescimento Infantil da Organização Mundial da Saúde para o índice estatura para idade, considerando-se com deficit de estatura as crianças que apresentaram esse índice dois escores-Z abaixo do valor mediano da população de referência. Empregou-se o teste t ou análise de variância na análise estatística, programa Statistical Package for the Social Sciences-16.0. RESULTADOS: As prevalências de deficiência de zinco no soro, inadequação dietética de zinco e deficit de estatura foram de 16,2%, 16,6% e 7,7%, respectivamente. A média de zinco no soro foi estatisticamente menor nas crianças de mães com baixo peso em comparação com as crianças de mães com peso normal. CONCLUSÃO: As crianças estudadas apresentaram risco moderado de deficiência de zinco, pois são indicadas prevalências significativas de baixos níveis séricos de zinco, de consumo inadequado de zinco e de desnutrição crônica.