以低苯丙氨酸饮食可有效地治疗PKU(即苯丙酮尿症)。早期诊断和细心的饮食疗法对于防止新生儿期的智力减退和增进智力是很重要的,而且可以减少因智力迟钝而住院的PKU病人的数目。可是近来注意到,一旦中断这种饮食之后,老PKU儿童的智力又趋变坏;此外,有一些临床表现,如湿疹、运动过度和异常脑电图偶而也会随血清苯丙氨酸水平的上升而表现出来。在美国易于购得的唯一的低苯丙氨酸产品是Lofenalac。大多数PKU病人对此反应良好,但有些病人则受不了或不能继续服用,特别是在病孩 PKA (hyponatremia) can be effectively treated with a low phenylalanine diet. Early diagnosis and careful diet therapy are important to prevent mental retardation and increase intelligence in the neonatal period, and can reduce the number of PKU patients hospitalized with mental retardation. However, it has recently been noted that the intelligence of older PKU children tends to deteriorate once the diet is discontinued; in addition, there are clinical manifestations such as eczema, hyperkinesia and abnormal EEG occasionally associated with serum phenylalanine levels Rise and show. The only low-phenylalanine product that is readily available in the United States is Lofenalac. Most PKU patients respond well, but some patients can not stand or can not continue to take, especially in sick children