Consumo alimentar de magnésio, potássio e fósforo por adolescentes de uma escola pública / Intake of magnesium, potassium and phosphorus in diets for adolescents of a government-run school

O presente estudo, do tipo transversal, teve como objetivo avaliar o consumo alimentar de magnésio, potássio e fósforo por 207 adolescentes do sexo feminino e masculino, com faixa etária de 15-17 anos, de uma escola pública de Petrolina - Pernambuco. As atividades foram iniciadas com a coleta dos dados alimentares por meio do Recordatório 24hrs; para a quantificação dos minerais foram utilizadas a tabela de medidas caseiras, a tabela brasileira de composição de alimentos e a tabela de composição nutricional dos alimentos consumidos no Brasil. Para comparar a ingestão destes minerais segundo sexo e faixa etária, utilizou-se as recomendações dispostas pelas DRIs. Com relação ao consumo mediano, apenas os adolescentes do sexo masculino apresentaram consumo de fósforo acima do recomendado. Os percentuais de inadequação foram elevados em ambos os sexos, principalmente para o consumo de magnésio (96,2% e 96%) e potássio (100% e 98,7%). O percentual de inadequação de fósforo apresentou-se superior para os meninos (67,6%) em relação ao sexo feminino (41,4%). O baixo consumo destes minerais pode levar ao comprometimento futuro do estado nutricional desta população; portanto, é de extrema importância o desenvolvimento de intervenções objetivando a melhora do comportamento alimentar.

Current transversal study evaluated the intake of magnesium, potassium and phosphorus by 207 female and male adolescents, within the 15 ­ 17 years bracket, of a government-run school in Petrolina PE Brazil. Food data were collected by a 24-h food record. Food-measurement table, the Brazilian table for food compositions and nutrition composition of food consumed in Brazil were employed to quantify the minerals. Recommendations by DRIs were used to compare ingestion of minerals according to gender and age bracket. In the case of median intake, only males presented phosphorus intake above the recommended dose. Inadequate percentages were high for both genders, especially in the intake of magnesium (96.2% and 96%) and potassium (100% and 98.7%). Phosphorus inadequacy percentage was higher for males (67.6%) when compared to that of females (41,4%). Low intake of the minerals may compromise the nutritional state of the population under analysis. Interventions are highly important for an improvement in food intake behavior.

STUDIES ON THE EFFECT OF POTASSIUM DEFICIENCY AND POTASSIUM REQUIREMENTS IN HOT ENVIRONMENTS / 营养学报

Potassium metabolism in young adult men exercising in the heat for six consecutive days and the effect of potassium deficiency in mice and rats induced by low potassium diet during heat exposure were observed. Increased potassium loss in sweat and lower potassium intake resulted in negative potassium balance. Individuals with a negative potassium balance had lower se- rum potassium levels and higher body temperature after exercise. Potassium deficient mice accomplished less work done (2.372 vs 4.253 Kg.M) but exih-ibited a markedly greater rate of heat gain (1.36 vs 0.87℃/Kg.M) as compared to the controls. The survival rate and cellular energy metabolism also decreasedThese observations suggest that prevention from potassium deficiency must be emphasized during prolonged physical activity under hot environments. According to the linear regression equations between potassium intake and balance, it is proposed that the potassium requirements in mild and medium physical activity in the heat are 40 and 60 mEq/day respectively, and the allowance of potassium in the latter may be 70-80 mEq/day.