RESUMO
OBJECTIVE: A 4-week pilot study was done with 26 preterm infants to evaluate whether a physical activity program would result in greater bone mineralization. DESIGN: Subjects were matched by birth weight, gender, and gestational age, and randomly assigned to the physical activity program (group EX; n = 13) or to the control group (group C; n = 13). Physical activity consisted of range of motion with passive resistance to all extremities for 5 to 10 minutes daily. Baseline and 4-week values were determined for both bone mineral analyses and serum levels of calcium, phosphate, alkaline phosphatase, parathyroid hormone, and 25-hydroxy-vitamin D. RESULTS: Despite similar nutrient intake at advised levels for preterm infants, EX infants gained more weight than control subjects (17.8 vs 13.4 gm/kg body weight per day; p = 0.01). A difference in radial bone mass and density change as determined by single-beam photon absorptiometry (+/- 2% error) was found between groups (p = 0.006 by analysis of covariance). Changes in bone width and in bone mineral content and density were enhanced by physical activity. Group EX infants had 12%, 18%, and 34% gains in bone width and in bone mineral density and content, respectively; group C infants had only a 2% gain in bone width and 11% and 14% losses from baseline in bone mineral content and density, respectively, during the 4-week study. Serum biochemical values were similar in the groups except for lower alkaline phosphatase levels in group EX. There was a negative association between bone mineral content and parathyroid hormone values: r = -0.83, p = 0.01. CONCLUSIONS: A physical activity program may increase the effects of adequate nutrition in healthy preterm very low birth weight infants by promoting weight gain and bone mass and by decreasing the risk of osteopenia.
Assuntos
Calcificação Fisiológica , Exercício Físico/fisiologia , Recém-Nascido Prematuro/fisiologia , Absorciometria de Fóton , Fosfatase Alcalina/sangue , Antropometria , Peso Corporal , Doenças Ósseas Metabólicas/prevenção & controle , Ingestão de Energia , Feminino , Humanos , Fenômenos Fisiológicos da Nutrição do Lactente , Recém-Nascido , Masculino , Hormônio Paratireóideo/fisiologiaRESUMO
Infants fed a soy formula supplemented with selenite had plasma and erythrocyte selenium values lower than those of infants fed human milk. However, plasma and erythrocyte glutathione peroxidase activities were normal, indicating that the physiologic requirement for selenium was being met.
Assuntos
Alimentos Fortificados , Alimentos Infantis , Selênio/sangue , Eritrócitos/química , Feminino , Alimentos Fortificados/análise , Glutationa Peroxidase/metabolismo , Humanos , Lactente , Alimentos Infantis/análise , Masculino , Leite Humano/química , Selênio/análiseRESUMO
The selenium status of 46 orally fed vitamin E-sufficient preterm infants (birth weight less than 1700 gm) was studied longitudinally for 3 weeks to determine the efficacy of selenium supplementation. Infants were fed either human milk (n = 21; 24 ng selenium/ml), preterm formula (n = 13; 7.8 ng selenium/ml), or preterm formula supplemented with sodium selenite (n = 12; 34.8 ng selenium/ml). Plasma and erythrocyte selenium and glutathione peroxidase activity and urinary and dietary selenium content were evaluated on study day 1 (day enteral feeds reached 100 kcal/kg/day) and weekly for 3 weeks. Throughout the study, selenium intakes of infants fed preterm formula plus sodium selenite were greater than those of infants fed human milk, which were greater than those of infants fed preterm formula (p less than 0.001). After 3 weeks no differences were observed among groups for plasma or erythrocyte selenium or glutathione peroxidase. Plasma selenium and glutathione peroxidase values within all groups were low compared with those reported for term infants fed human milk. Whereas urinary selenium levels of infants fed preterm formula plus sodium selenite were greater than those of infants fed preterm formula at weeks 1 and 2 (p less than 0.01), infants fed human milk and preterm formula had lower levels at week 3 than on study day 1 (p less than 0.05). We conclude that blood selenium measurements typically used to monitor selenium status do not reflect dietary selenium intakes of orally fed preterm infants.