Remer Thomas, Dimitriou Triantafillia, Manz Friedrich
Department of Nutrition and Health, the Research Institute of Child Nutrition, Dortmund, Germany.
Am J Clin Nutr. 2003 May;77(5):1255-60. doi: 10.1093/ajcn/77.5.1255.
There is increasing evidence that acid-base status has a significant effect on high-intensity physical performance, urolithiasis, and calcium metabolism. Experimental studies in adults showed that renal net acid excretion (NAE) can be reliably estimated from the composition of diets.
We investigated whether a reasonable estimation of NAE is also possible from the dietary records of free-living children and adolescents.
Healthy children (aged 8 y; n = 165) and adolescents (aged 16-18 y; n = 73) each collected a 24-h urine sample and completed a weighed diet record on the same day. Urinary NAE was analyzed (NAE(an)) and estimated (NAE(es)). Potential renal acid load (PRAL), the diet-based component of NAE(es), corrects for intestinal absorption of ingested minerals and sulfur-containing protein. A urinary excretion rate of organic acids (OAs) proportional to body surface area was assumed for the complete estimate (NAE(es) = PRAL + OA(es)).
Significant (P < 0.001) correlations between NAE(es) and NAE(an) were seen in the children (r = 0.43) and the adolescents (r = 0.51). A simplified estimate based on only 4 components of dietary PRAL (protein, phosphorus, potassium, and magnesium) yielded almost identical associations. Mean simplified NAE(es) (32.6 +/- 13.9 and 58.4 +/- 22.0 mEq/d in the children and the adolescents, respectively) agreed reasonably with NAE(an) (32.4 +/- 15.5 and 52.8 +/- 24.3 mEq/d, respectively).
Predicting NAE from dietary intakes, food tables, and anthropometric data is also applicable during growth and yields appropriate estimates even when self-selected diets are consumed. The PRAL estimate based on only 4 nutrients may allow relatively simple assessment of the acidity of foods and diets.
越来越多的证据表明，酸碱状态对高强度身体机能、尿石症和钙代谢有显著影响。针对成年人的实验研究表明，可根据饮食成分可靠地估算肾净酸排泄量（NAE）。
我们调查了能否根据自由生活的儿童和青少年的饮食记录合理估算NAE。
健康儿童（8岁；n = 165）和青少年（16 - 18岁；n = 73）均收集了一份24小时尿液样本，并在同一天完成了称重饮食记录。分析了尿NAE（NAE(an)）并进行了估算（NAE(es)）。潜在肾酸负荷（PRAL）是NAE(es)基于饮食的组成部分，可校正摄入矿物质和含硫蛋白质的肠道吸收情况。在完整估算中（NAE(es) = PRAL + OA(es)），假定有机酸（OAs）的尿排泄率与体表面积成正比。
在儿童（r = 0.43）和青少年（r = 0.51）中，NAE(es)与NAE(an)之间均存在显著（P < 0.001）相关性。仅基于饮食PRAL的4种成分（蛋白质、磷、钾和镁）进行的简化估算产生了几乎相同的关联。儿童和青少年的平均简化NAE(es)分别为（32.6 ± 13.9和58.4 ± 22.0 mEq/d），与NAE(an)（分别为32.4 ± 15.5和52.8 ± 24.3 mEq/d）合理相符。
根据饮食摄入量、食物表和人体测量数据预测NAE在生长期间同样适用，即使食用自选饮食也能得出合适的估算值。仅基于4种营养素的PRAL估算可能会使食物和饮食酸度的评估相对简单。
