The effect of diet on Paraoxonase 1/Arylesterase activities in patients with disorders of galactose metabolism.

Summary Objective  To investigate the effects of diet on the antiatherogenic enzyme Paraoxonase 1/Arylesterase (PON1/Aryl) activities in patients with disorders of galactose metabolism. Patients and methods  Eleven poorly dietary controlled children with classical galactosaemia (GALT deficiency), 7 with epimerase deficiency and 12 with duarte 1 variant ‘off diet’ underwent clinical and laboratory investigations before and after 10 days on galactose restricted diet whereas controls (N = 20) were examined once. Serum lipids, lipoproteins and apolipoprotein A1 (ApoA1) were measured with routine methods, PON1/Aryl activities and total antioxidant status (TAS) spectrophotometrically, and galactose-1-phosphate (Gal-1-P) enzymatically. Results  Lipids, lipoproteins, ApoA1, PON1/Aryl, TAS remained unaltered in all groups, except in those with classical galactosaemia pre- versus postdiet. In patients with classical galactosaemia, TAS, PON1, Aryl (0·98 ± 0·2 mmol/l, 60 ± 12 U/min/ml, 56 ± 16 KU/min/ml, respectively) were significantly reduced prediet as compared with those postdiet (1·63 ± 0·2 mmol/l, 136 ± 15 U/min/ml, 112 ± 18 KU/min/ml, respectively; P < 0·001) and controls. The enzyme activities positively correlated with TAS (r = 0·56, P < 0·001) in all groups and negatively with Gal-1-P (r = –0·54, P < 0·001) in group with GALT deficiency. Conclusions  Low TAS and high Gal-1-P levels may reduce PON1/Aryl activities. Patients with classical galactosaemia, when on strict diet, may benefit with a generous antiatherogenic capacity.