María Luz Pita Martín de Portela

Interrelationship between bone turnover markers and dietary calcium intake in pregnant women: a longitudinal study

This longitudinal study evaluated bone turnover and the interrelationship between changes in bone biomarkers and habitual dietary calcium intake during pregnancy in a group of women ranging widely with regard to dietary calcium intake. Thirty-nine healthy pregnant and 30 nonpregnant women were studied. Calcium, phosphorus, 1alpha,25-dihydroxyvitamin D (1,25diHOD), bone alkaline phosphatase (bALP), carboxyterminal propeptides of type I procollagen (PICP) and carboxyterminal telopeptides of type I collagen (betaCTX and ICTP) were measured in serum and calcium, and creatinine and aminoterminal telopeptide (NTX) were determined in urine. Serum calcium and phosphorus did not change but the urinary Ca/Creat ratio and 1,25diHOD increased throughout pregnancy (P < 0.001 and P < 0.0001, respectively). Serum b-ALP and PICP increased during the last two trimesters (P < 0.0001 and P < 0.001, respectively). All studied bone resorption markers increased compared to nonpregnant values throughout pregnancy. The highest increment was observed in the third trimester. The level of significance decreased as follows: betaCTX > NTX >ICTP. Serum 1,25 diHOD versus calcium intake showed a positive and significant correlation (r = 0.51, P < 0.02). A negative correlation between the absolute change in betaCTX, NTX, and b-ALP between the third and second trimester and calcium intake at the end of pregnancy was observed in pregnant women who did not cover adequately calcium intake requirements (r = -0.47, P < 0.03; r = -0.41, P < 0.05; and r = -0.43, P < 0.05, respectively). These results suggest that skeletal response to pregnancy may not be entirely independent of maternal calcium intake, especially in women with usually low calcium intake. In summary, not only hormonal changes in calcium metabolism that occur during pregnancy but also other considerations, such as low dietary calcium intake, may lead to an increment in the biological activity of the skeleton. Additional studies must be conducted to confirm our findings and to gain a better understanding of skeletal response to a low calcium intake during pregnancy.

Déficit de vitamina A en una población infantil de alto riesgo social en Argentina

Introduccion: La vitamina A es muy importante en su rol nutricional y es un factor critico en la salud y supervivencia del nino. Objetivo: El objetivo de este trabajo fue evaluar los niveles de vitamina A en ninos provenientes de hogares con necesidades basicas insatisfechas (NBI) de tres areas del pais y determinar las relaciones que pudieran existir entre esos niveles y ciertas variables clinicas, antropometricas, alimentarias y socieconomicas. Poblacion: Todos los ninos de 0,5 a 2,11 anos de hogares con NBI que concurrie-ron de septiembre a diciembre de 1995 a determinados centros de salud apara control con los medicos involucrados en este estudio. Fueron criterios de exclu-sion los ninos con enfermedades croni-cas o actuales, no asi los desnutridos. Se estudiaron en Buenos Aires 268 ninos, en Chaco 140 ninos y en corrientes 195 ninos. Material y metodos: En cada centro de salud el medico realizo: recoleccion de informacion mediante: A) un cuestiona-rio con datos personales, antecedentes nutricionales, antecedentes patologicos, inmunizaciones, B) examen clinico y evaluacion antropometrica, c)extraccion de muestras de sangre de cada nino para dosaje de retinol plasmatico de acuerdo a tecnicas estandarizadas. El limite inferior normal de retinol fue establecido en 20 ug/dl. Resultados: Se encontro una alta prevalencia de deficit de vitamina A en 26%, 32% y 46% de los ninos estudia-dos en Buenos Aires, Chaco y Corrientes, respectivamente, no se encontraron relaciones entre el retinol y las variables socioeconomicas, de morbilidad y nutricionales. Conclusioens: Los resultados sobre 603 ninos estudiados revelan severo deficit de vitamina A en ninos de 0,5 a 2,11 anos de edad pertenecientes a hogares con NBI en tres areas estudiadas en Buenos Aires, Chaco y Corrientes

Influence of dietary calcium concentration on body size and bone composition in rats during recovery from malnutrition

OBJECTIVE The purpose of our study was to assess the influence of different levels of calcium (Ca) in a diet containing 30% protein on the rehabilitated of the body size from protein-energy malnutrition (PEM) and to establish the optimal Ca/protein ratio for attaining a normal body composition. METHODS Weanling female Wistar rats were fed with protein-free diet up to a weight deficit of 20 +/- 1%. Then they were arranged in groups (TO) and fed diets with 30% protein and 0.0, 0.2, 0.4, 0.6, 0.9 or 1.2% Ca for 28 days (T28). Food and deionized water were given ad libitum. Body weight and length were recorded every 3 days. At T28, the animals were sacrificed to determine femur composition. RESULTS At T13, weight-for-age (W/A) was within the normal range for rats consuming > or = 0.6% Ca. At T28 all groups showed adequate W/A. Although length-for-age was adequate during rehabilitated period, rate of weight gain improved when Ca was > or = 0.6%. Femur length did not show significant difference between groups. Total femur Ca content and mg Ca/g of dry-weight tissue increased with increments in dietary Ca concentration and tended to plateau with 0.4% Ca. Ca/P ratio reached the highest value with 0.9% Ca. CONCLUSIONS Our findings indicate that at a dietary protein level of 30% the Ca/protein ratio is a limiting factor in attaining of normal body size; this is achievable when Ca concentration is 1.2% and the Ca/protein ratio is 0.04.

Prebióticos en salud infantil

The composition of human milk is the main base for the development of infant formulas concerning its macronutrients and micronutrients contents and bioactive compounds. Technological advances in the composition of human milk have identified a great number of bioactive compounds such as prebiotics which are responsible for immunological protection and the prevention of different pathologies. In order to achieve similar benefits, they are part of the contents of infant formulas.