EFFECT OF DOUBLE-BLIND CROSSOVER SELENIUM SUPPLEMENTATION ON BIOLOGICAL INDEXES OF SELENIUM STATUS IN CYSTIC-FIBROSIS PATIENTS

Twenty-seven cystic fibrosis patents received selenium supplementation (2.8 mug of sodium selenite per kilogram of body weight per day) or a placebo. This 5-month trial was conducted as a double-blind, placebo- controlled study. After an interval of 2 months, treatments of the two groups were interchanged (crossed over) for another 5-month period. A group of healthy subjects, living in the same area, was investigated simultaneously. No selenium deficiency was found either in plasma or i n erythrocytes before the supplementation. This result was inconsisten t with a previous study performed in 1988 in our laboratory. This chan ge in selenium status can be explained by progress in the nutritional nursing care of children and by the addition of selenium to the diet. During the study, selenium concentrations in plasma decreased when pat ients received placebo treatment and increased during selenium intake. In one of the two groups a similar variation was found for glutathion e peroxidase activities in plasma and erythrocytes, whereas erythrocyt e selenium was normal and did not change in any group. Nowadays, in th e Grenoble area, the selenium status of cystic fibrosis patients is cl ose to normal. Nevertheless, this study indicates a fragile equilibriu m, given that selenium concentrations can be lowered by placebo or mil dly increased by supplementation.