Polyunsaturated fatty acid status in patients with phenylketonuria.

To determine whether the n-6 and n-3 polyunsaturated fatty acid levels can be affected by the PKU diet, fatty acid composition was studied in PKU subjects and controls together with their lipid intake. The study population consisted of 40 PKU patients treated with a phenylalanine-restricted diet. Controls were 50 children on whom preoperative tests had been carried out for minor surgery. Methyl esters were obtained from plasma and red blood-cells and separated by gas chromatography. PKU patients showed lower docosahexaenoic acid levels (22: 6 n-3) (p < 0.001) and higher n-6 series levels in plasma (18:2 n-6) (p < 0.001) and in red blood-cells (20: 4 n-6) (p < 0.001) than the control population. Since docosahexaenoic and arachidonic acids are fundamental structural components for normal brain development, it seems necessary to consider a dietary adjustment in these patients.