Clinical trial of 'off diet' older phenylketonurics with a new phenylalanine-free product.

Ten PKU subjects were treated with Product 196 for one year. Product 196 is a special phenylalanine-free dietary supplement consisting primarily of essential amino acids, carbohydrate, Vitamin C and some minerals, made by Scientific Hospital Supplies Limited, Liverpool, England. It is intended for persons with phenylketonuria who are not consuming a phenylalanine-restricted diet. During the year that the 10 subjects were on the product, they remained asymptomatic, maintained their weight and appeared healthy. Subjective behavioural improvement was noted in six but no significant changes in intelligence were noted.