Selenium and glutathione peroxidase variations induced by polyunsaturated fatty acids oral supplementation in humans.
Serum and erythrocyte selenium, erythrocyte and platelet glutathione-peroxidase (GSH-Px) activities, and erythrocyte reduced glutathione (GSH) content were measured in 25 healthy adult individuals before and after daily supplementation with 20 ml of fish oil for 10 weeks. Serum-Se decreased from 0.83 +/- 0.01 mumol/l to 0.75 +/- 0.02 mumol/l (mean +/- S.E.M.) (P less than 0.01); erythrocyte-Se decreased from 4.39 +/- 0.17 nmol/g hemoglobin (Hb) to 2.83 +/- 0.15 nmol/g (P less than 0.001). GSH-Px activities increased both in erythrocytes (6.93 +/- 0.24 iu/g vs 8.18 +/- 0.27 iu/g Hb, P less than 0.01) and in platelets (69.2 +/- 2.8 iu/g vs 90.9 +/- 3.6 iu/g protein, P less than 0.001). The concentration of GSH in erythrocytes fell from 9.56 +/- 0.29 mumol/g Hb to 5.90 +/- 0.30 mumol/g Hb (P less than 0.001). The effects on plasma lipids were evident only for triglycerides (before 1.96 +/- 0.16 mmol/l, after 1.75 +/- 0.14 mmol/l, P less than 0.001). We hypothesise the enrichment of erythrocyte and platelet membranes with polyunsaturated fatty acids (PUFAs), following fish oil intake, can generate increased amounts of lipid peroxides and thus allosterically activate GSH-Px: with time this is harmful for the integrity of the enzyme molecule and Se release may result. We suggest that the Se status of individuals given PUFAs is assessed before and during intake; Se supplements should only be given when serum and/or erythrocyte Se are reduced.
Bellisola
G
G
Laboratory of Clinical Chemistry, C.O.C Valeggio s. M., Italy.
Galassini
S
S
Moschini
G
G
Poli
G
G
Perona
G
G
Guidi
G
G
D000284:Administration, Oral; D000328:Adult; D001792:Blood Platelets / Q000201:enzymology; D002784:Cholesterol / Q000097:blood; D004041:Dietary Fats / Q000494:pharmacology; D004912:Erythrocytes / Q000201:enzymology; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D005260:Female; D005395:Fish Oils / Q000494:pharmacology; D014644:Genetic Variation; D005978:Glutathione / Q000097:blood; D005979:Glutathione Peroxidase / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012643:Selenium / Q000097:blood*; D014280:Triglycerides / Q000097:blood
D004041:Dietary Fats; D005231:Fatty Acids, Unsaturated; D005395:Fish Oils; D014280:Triglycerides; D002784:Cholesterol; D005979:Glutathione Peroxidase; D005978:Glutathione; D012643:Selenium