Grantham-McGregor Sally
Center for International Child Health, Institute of Child Health, University College London, 30, Guilford St, London.
Food Nutr Bull. 2005 Jun;26(2 Suppl 2):S144-58. doi: 10.1177/15648265050262S204.
Studies of an association between school performance (enrollment, attendance, achievement, classroom behavior, and school drop-out) and nutritional status are discussed and the evidence of an effect of school meals evaluated. Many studies have shown associations between hunger, poor dietary intakes, stunting, underweight, and poor school performance after controlling for socioeconomic conditions. However, it remains possible that unmeasured socioeconomic variables could explain the relationship. Rigorous short-term studies of missing breakfast have generally found detrimental effects on children's cognition whereas studies of providing breakfast have shown benefits particularly in malnourished children. Classroom conditions may modify the effects of breakfast on behavior. There are extremely few longer term studies of the effects of giving school meals. Nearly all involved breakfast and very few had randomized controlled designs. Studies comparing participants with non-participants or comparing matched schools have found benefits (but bias due to self-selection) of receiving breakfast; inadequate matching of schools also remains possible. One longer term randomized controlled trial found benefits associated with attendance and arithmetic performance. In conclusion, most studies of giving breakfast have found benefits to school performance but many had serious design problems, were short-term, and were not conducted in the poorest countries. In order to advise policy makers correctly, there is an urgent need to run long-term randomized controlled trials of giving school meals in poor countries and to determine the effects of age and nutrition status of the children, the quality of the school, and the timing of the meal. The special needs of orphans should also be considered.
本文讨论了学校表现(入学率、出勤率、成绩、课堂行为和辍学情况)与营养状况之间关联的研究,并评估了学校膳食影响的证据。许多研究表明,在控制社会经济状况后,饥饿、不良饮食摄入、发育迟缓、体重不足与学校表现不佳之间存在关联。然而,未测量的社会经济变量仍有可能解释这种关系。对不吃早餐的严格短期研究通常发现对儿童认知有不利影响,而提供早餐的研究则表明尤其对营养不良的儿童有益。课堂环境可能会改变早餐对行为的影响。关于提供学校膳食影响的长期研究极少。几乎所有研究都涉及早餐,且很少有随机对照设计。比较参与者与非参与者或比较匹配学校的研究发现,吃早餐有好处(但存在自我选择导致的偏差);学校匹配不充分也仍有可能。一项长期随机对照试验发现与出勤率和算术成绩相关的益处。总之,大多数提供早餐的研究都发现对学校表现有好处,但许多研究存在严重的设计问题,是短期的,且并非在最贫穷国家进行。为了正确地为政策制定者提供建议,迫切需要在贫穷国家开展关于提供学校膳食的长期随机对照试验,并确定儿童的年龄和营养状况、学校质量以及用餐时间的影响。还应考虑孤儿的特殊需求。