Nutritional status of some micronutrients and trace elements in patients with phenylketonuria

ABSTRACT

Children with special needs; those having inborn errors of metabolism are prone to certain micronutrient deficiencies either due to rigid therapeutic dietary restriction, aversion to certain food stuffs or due to recurrent episodes of vomiting and diarrhea. This will eventually ensue if no parallel specific elemental replacement measures are carried out. Micronutrient deficiencies often occur concurrently, and there are many interactions between micronutrients. Children with phenylketonuria [PKU] are treated with semi-synthetic formula containing low phenylalanine [Phe] content. It provides the majority of protein and energy in the diet while the rest of phenylalanine are met by low protein natural foods. Because of the restricted intake of high biological value protein, children with PKU are often expected to have lower than normal plasma concentrations of certain micronutrients. The aim of the study is to assess the effects of phenylalanine restricted diet on the growth of our PKU patients after one year of dietary management. We also aimed to investigate the nutritional status of the following trace elements and micro-nutrients; zinc, copper, vitamins C, E, A, and B-carotene among 17 PKU patients following dietary coupled with multivitamin supplementation. Data were compared to those of their matched normal controls. PKU patients were found to have marginal vitamin A deficiency as the mean plasma level was 25.2 +/- 6.62ug/dl versus 48.5 +/- 10.1ug/dl of their control. The difference was very highly significant [p<0.0001]. Mean plasma levels of B-carotene was also less than that of controls with a highly significant difference [50.65 +/- 15.37ug/dl Vs.-75.80 +/- 19.60ug/dl; p<0.001]. Mean plasma levels of zinc, copper, vitamins C and E were comparable to those of controls without statistical significance [p>0.05]. Physical growth parameters were not significantly different between the two groups. A basic nutritional care plan for dietary intervention managing PKU children should involve periodic assessment of protein and calorie nutritional status in addition to regular careful evaluation of micronutrient nutritional status