Trace mineral composition of human breast milk from Brazilian mothers.

BACKGROUND: Human milk is a dynamic food and some important differences in composition can be found between the milk from preterm and terms infants. Additionally, in some situations, the mother's own milk is unavailable and the use of milk from human milk banks is considered as the most appropriate substitute. In this way, concentrations of trace elements (Ba, Cu, Fe, Mn, Mo, Se, Sr, and Zn) were determined in human milk, considering the differences about preterm and term human milk and its processing in a human milk bank. METHODS: A total of 156 samples were analyzed, which were divided in three groups: samples collected at the hospital at bedside (BS, 60 samples) from mothers of preterm infants and samples from mothers of term infants collected in a human milk bank without pasteurization (WP, 49 samples) and pasteurized by the Holder procedure (P, 47 samples). The analyzes were conducted by inductively coupled plasma mass spectrometry (ICP-MS) after the treatment of the samples with acid mineralization assisted by microwave radiation. RESULTS: Concentrations varied in a range of 0.6-88.2 µg/L for Ba, 78.6-954.5 µg/L for Cu, 24.2-5229.2 µg/L for Fe, 0.4-42.6 µg/L for Mn, 0.1-39.1 µg/L for Mo, 2.5-70.6 µg/L for Se, 8.9-187.5 µg/L for Sr and 76.3-17727.2 µg/L for Zn. Significant differences (p < 0.05) were found between preterm (BS) and term human milk (WP and P) for Ba, Cu, Mo, Se, and Zn, whereas the processing of the donated milk by Holder pasteurization did not influence the concentration of the studied trace elements. The milk of term infants does not attend the recommended daily intake (RDI) of Zn and for preterm infants the RDI of Fe and Mn is not achieved. CONCLUSIONS: The higher concentrations of Cu, Mo, Se and Zn observed in milk from mothers of preterm infants indicate that the milk to be offered for these high-risk neonates in neonatal intensive care units should contain higher levels of these trace elements. Besides, considering the RDI, the milk of term infants should be fortified with Zn, whereas the milk of preterm infants should be fortified with Fe.

Composição eletrolítica e mineral do leite de lactantes a termo pré e pós-pasteurização e de leite cru de mães de recém-nascidos pré-termo / Electrolyte and mineral composition of term donor human milk before and after pasteurization and of raw milk of preterm mothers

RESUMO Objetivo: Determinar e comparar as concentrações de eletrólitos e minerais no leite humano em três grupos: amostras analisadas antes e após pasteurização de lactantes doadoras a termo e amostra de leite cru colhida à beira do leito de mães de recém-nascidos pré-termo. Métodos: Estudo descritivo de corte transversal. Foram dosadas concentrações de cálcio (Ca), fósforo (P), magnésio (Mg), sódio (Na) e potássio (K) em amostras aleatórias de leite humano nos três grupos. As amostras foram analisadas por mineralização ácida assistida por radiação micro-ondas e posteriormente por espectrometria de emissão óptica com plasma indutivamente acoplado e expressas em mg/L, com cálculo de médias e desvio padrão. A comparação entre os grupos foi feita por análise de variância (ANOVA)/teste de Tukey. Nível de significância aceito de 5%. Resultados: Observou-se redução significante dos teores de Ca (259,4±96,8 vs. 217,0±54,9; p=0,003), P (139,1±51,7 vs. 116,8±33,3; p=0,004) e K (580,8±177,1 vs. 470,9±109,4; p<0,0001) após a pasteurização. As amostras de leite cru colhidas à beira do leito apresentaram teores estatisticamente mais elevados de Na (2 vezes) do que o leite a termo de doadora. Ca e P só atingiriam a ingestão recomendada pela European Society of Pediatric Gastroenterology, Hepatology and Nutrition se o leite materno fosse ofertado em volume de 60 mL a cada 3 horas. Concentrações de Mg não diferiram entre os grupos. Conclusões: Houve uma redução significativa de Ca, P e K nas amostras após pasteurização e os valores de Na no leite cru coletado à beira do leito foram superiores àqueles pré-pasteurização.

ABSTRACT Objective: To determine and compare the concentrations of electrolytes and minerals in three different types of maternal milk samples: term donor milk before pasteurization, term donor milk after pasteurization and raw milk of mothers of preterm newborns at bedside. Methods: Descriptive cross-sectional study. Concentrations of calcium (Ca), phosphorous (P), magnesium (Mg), sodium (Na) and potassium (K) were measured in random samples of three human breast milk groups. Samples were analyzed using acid mineralization assisted by microwave radiation and further analysis by inductively coupled plasma optical emission spectrometry. Concentrations were expressed in mg/L, described as mean and standard deviation. The one-way ANOVA and Tukey's post-test were applied to determine the variability between the means of each group. Significance level was set at 5%. Results: There was a significant reduction in the content of Ca (259.4±96.8 vs. 217.0±54.9; p=0.003), P (139.1±51.7 vs. 116.8±33.3; p=0.004) and K (580.8±177.1 vs. 470.9±109.4; p<0.0001) in donor maternal milk before and after pasteurization. Samples of raw milk presented higher contents of Na than the donated milk (twice). The elements P and Ca would only reach the daily intake levels recommended by the European Society of Pediatric Gastroenterology, Hepatology and Nutrition if at least 60 mL of milk could be offered every 3 hours. Mg levels were not different between the three groups. Conclusions: There was a significant reduction in Ca, P and K levels in samples after pasteurization. The Na value in raw milk, collected at bedside, was higher than in the samples of donor's milk before pasteurization.

ELECTROLYTE AND MINERAL COMPOSITION OF TERM DONOR HUMAN MILK BEFORE AND AFTER PASTEURIZATION AND OF RAW MILK OF PRETERM MOTHERS. / COMPOSIÇÃO ELETROLÍTICA E MINERAL DO LEITE DE LACTANTES A TERMO PRÉ E PÓS-PASTEURIZAÇÃO E DE LEITE CRU DE MÃES DE RECÉM-NASCIDOS PRÉ-TERMO.

OBJECTIVE: To determine and compare the concentrations of electrolytes and minerals in three different types of maternal milk samples: term donor milk before pasteurization, term donor milk after pasteurization and raw milk of mothers of preterm newborns at bedside. METHODS: Descriptive cross-sectional study. Concentrations of calcium (Ca), phosphorous (P), magnesium (Mg), sodium (Na) and potassium (K) were measured in random samples of three human breast milk groups. Samples were analyzed using acid mineralization assisted by microwave radiation and further analysis by inductively coupled plasma optical emission spectrometry. Concentrations were expressed in mg/L, described as mean and standard deviation. The one-way ANOVA and Tukey's post-test were applied to determine the variability between the means of each group. Significance level was set at 5%. RESULTS: There was a significant reduction in the content of Ca (259.4±96.8 vs. 217.0±54.9; p=0.003), P (139.1±51.7 vs. 116.8±33.3; p=0.004) and K (580.8±177.1 vs. 470.9±109.4; p<0.0001) in donor maternal milk before and after pasteurization. Samples of raw milk presented higher contents of Na than the donated milk (twice). The elements P and Ca would only reach the daily intake levels recommended by the European Society of Pediatric Gastroenterology, Hepatology and Nutrition if at least 60 mL of milk could be offered every 3 hours. Mg levels were not different between the three groups. CONCLUSIONS: There was a significant reduction in Ca, P and K levels in samples after pasteurization. The Na value in raw milk, collected at bedside, was higher than in the samples of donor's milk before pasteurization.

OBJETIVO: Determinar e comparar as concentrações de eletrólitos e minerais no leite humano em três grupos: amostras analisadas antes e após pasteurização de lactantes doadoras a termo e amostra de leite cru colhida à beira do leito de mães de recém-nascidos pré-termo. MÉTODOS: Estudo descritivo de corte transversal. Foram dosadas concentrações de cálcio (Ca), fósforo (P), magnésio (Mg), sódio (Na) e potássio (K) em amostras aleatórias de leite humano nos três grupos. As amostras foram analisadas por mineralização ácida assistida por radiação micro-ondas e posteriormente por espectrometria de emissão óptica com plasma indutivamente acoplado e expressas em mg/L, com cálculo de médias e desvio padrão. A comparação entre os grupos foi feita por análise de variância (ANOVA)/teste de Tukey. Nível de significância aceito de 5%. RESULTADOS: Observou-se redução significante dos teores de Ca (259,4±96,8 vs. 217,0±54,9; p=0,003), P (139,1±51,7 vs. 116,8±33,3; p=0,004) e K (580,8±177,1 vs. 470,9±109,4; p<0,0001) após a pasteurização. As amostras de leite cru colhidas à beira do leito apresentaram teores estatisticamente mais elevados de Na (2 vezes) do que o leite a termo de doadora. Ca e P só atingiriam a ingestão recomendada pela European Society of Pediatric Gastroenterology, Hepatology and Nutrition se o leite materno fosse ofertado em volume de 60 mL a cada 3 horas. Concentrações de Mg não diferiram entre os grupos. CONCLUSÕES: Houve uma redução significativa de Ca, P e K nas amostras após pasteurização e os valores de Na no leite cru coletado à beira do leito foram superiores àqueles pré-pasteurização.