Controversies in the composition of infant formulas

Padrão alimentar de lactentes residentes em áreas periféricas de Fortaleza

Este estudo caracterizou o padrão alimentar de 96 crianças menores de um ano assistidas pelo Fundo Cristão para Crianças nos bairros Álvaro Weyne e Presidente Kennedy, na cidade de Fortaleza, Brasil. Os dados foram levantados por meio de entrevista domiciliar, utilizando o método recordatório 24h para conhecimento das quantidades dos alimentos consumidos, e um formulário contendo perguntas estruturadas sobre a prática do aleitamento materno e idade de introdução dos alimentos de desmame. Os resultados indicaram que o aleitamento materno misto predomina (68%) sobre o aleitamento artificial (32%) e exclusivo (10%) e que 7% das crianças nunca receberam leite materno. Porém, até o final do décimo mês de vida, 53% das crianças ainda são amamentadas. Mingau lácteo, preparado com leite de vaca não modificado, constitui a alimentação básica de desmame. Do ponto de vista nutricional, as dietas são desbalanceadas, sendo o ferro o nutriente mais deficiente. Devem ser intensificados os esforços na promoção da alimentação infantil apropriada.

Dietary modulation of intestinal fructose transport and GLUT5 mRNA expression in hypothyroid rat pups

BACKGROUND

Intestinal fructose transport rates or GLUT5 mRNA levels typically show a two- to threefold increase after weaning in rats allowed to wean normally but can be enhanced precociously by high-fructose diets during early weaning. Developmental increases in serum thyroxine levels coincide with the onset of weaning and have been linked to changes in intestinal sucrase and lactase activities.

METHODS

Rat pups were made hypothyroid by giving the dam 0.01% propylthiouracil as drinking water from day 18 of gestation. The hypothyroid pups and age-matched euthyroid control pups were then fed high-fructose or high-glucose solutions by gavage, twice a day starting at 17 days of age for 3 days, and then killed at 20 days of age.

RESULTS

Serum thyroxine levels were five times lower in the hypothyroid pups. Rates of intestinal fructose uptake in the proximal and middle small intestine were 2.0 to 2.5 times higher in the hypothyroid and euthyroid pups fed high-fructose solution than in littermates fed high-glucose solution or those allowed to wean normally with the dam. Intestinal glucose uptake also increased in hypothyroid but not in euthyroid pups fed high-fructose or high-glucose solutions. GLUT5 mRNA levels increased in euthyroid and hypothyroid pups fed high fructose and paralleled the increase in fructose uptake.

CONCLUSION

During weaning, dietary fructose can precociously enhance intestinal fructose uptake and GLUT5 mRNA expression, independent of developmental increases in serum thyroxine levels. Modest changes in glucose transport rates indicate that nonspecific mechanisms may provide a minor contribution to diet-induced changes in nutrient absorption in hypothyroid pups.