Calcium, phosphorus and magnesium balance: FM 85 fortification of human milk does not meet mineral needs of extremely low birthweight infants

Abstract

Objective: Extremely low birthweight ( < 1000 g) infants are growing rapidly and their nutritional requirements for calcium, phosphorus, magnesium are high. Design: Prospective, mineral balance. Setting: The study was carried out at the Department of Neonatology, Virchow-Hospital, Charité Berlin and the Department of Molecular Trace Element Research, Hahn-Meitner-Institute Berlin. Subjects: Nineteen infants < 1000 g birthweight were admitted, nine infants dropped out and 10 infants (birthweight 730 -995 g), fed fortified human milk were included. Intervention: We collected infant's urine and feces for 72 h, a sample of human milk and infant's blood at 7 and 12 weeks of age. Elements were measured by inductively coupled plasma atomic emission spectrophotometry. Results: Mean (s.d.) mineral concentration in milk was low especially at 12 weeks: calcium 9.88 ( AE 3.58) mmol=l, phosphorus 7.02 ( AE 3.81) mmol=l, magnesium 1.59 ( AE 0.54) mmol=l. Calcium retention was minimal or negative during the study, whereas phosphorus and magnesium balances were positive. Caffeine and diuretics increased mineral excretion. Serum alkaline phosphatase was mostly < 800 U=l, and 162 U=l in one infant with zinc deficiency at 12 weeks. Alkaline phosphatase correlated with absorption and retention of phosphorus, and with longitudinal growth. Conclusions: Infants < 1000 g have high nutritional needs for calcium, phosphorus and magnesium, which are not met by a human milk fortifier widely used in Europe. Controlled trials are needed to assess requirements, duration and risks of mineral supplementation.

Vitamin D Deficiency and Calcium Absorption during Childhood

“…Using a commercially available human milk fortifier, Schanler and Abrams [1] reported that net calcium retention was 104 AE 36 mg/ kg/d in premature infants, a value approximating the in utero accretion rate during the third trimester. These retention values are well above those achieved using earlier human milk fortifiers [16] and those more recently reported using a human milk fortifier not used in the United States [19]. That fortifier led to minimally positive calcium retention and therefore little if any benefit to the baby.…”

Influence of the Nutrition on Bone Health of Children and Adolescents

“…In the case of calcium, their daily loss (through excretion in the urine, fecal and dermal) are estimated at 420 mg/day. Calcium is absorbed in the intestine not ever exceeding 30% of the total amount ingested [18]. For absorption, calcium must compete with other substances such as phytates and oxalates act by inhibiting its absorption.…”

Comparação entre duas dietas à base de leite humano em relação ao crescimento e à mineralização óssea de recém-nascidos de muito baixo peso

“…Assume-se, atualmente, que a alimentação enteral dos recém-nascidos pré-termo deva ser iniciada o mais preco-cemente possível, com leite humano, preferencialmente de suas próprias mães, recomendando-se fórmula especial para prematuros se não houver disponibilidade de LH (9,21,22) . Contudo, quando se atinge o volume enteral total, o LH deve ser suplementado, a fim de fornecer adequado aporte de nutrientes (23,24) , pois mesmo o LH da própria mãe do prematuro não supre todas as suas necessidades e pode não proporcionar ganho ponderal adequado (7,9,24) .…”

“…Ao final do estudo, os níveis de fosfatase alcalina das crianças de ambos os grupos eram menores do que os iniciais, sendo os valores médios do Grupo B mais baixos do que os do Grupo A, indicando maior atividade osteoblástica nas crianças deste grupo, o que sugere maior remodelação óssea ou solubilização de hidroxiapatita devido à menor absorção de fósforo e cálcio da dieta A (LH+FM 85 ® ), lembrando-se que esta dieta oferece 25% mais cálcio e fósforo que a dieta B. Uma possível explicação para este achado seria a menor absorção desses minerais devido à menor solubilidade do aditivo então disponível e de seus sais de cálcio e fósforo, com consequente menor biodisponibilidade destes micronutrientes no LH+FM 85 ® em relação ao LH adicionado com fórmula para prematuros (3,4) . Deve-se ainda ressaltar que o aditivo FM 85 ® recebeu modificações em sua formulação em relação ao produto oferecido neste estudo, obviamente para aprimorá-lo, pois outros autores verificaram que sua adição ao LH não supria as necessidades de minerais de prematuros extremos (4,23,27) .…”