Improved antioxidant and fatty acid status of patients with cystic fibrosis after antioxidant supplementation is linked to improved lung function.
BACKGROUND
Oxidative stress, as measured by 8-iso-prostaglandin F(2)(alpha) (8-iso-PGF(2)(alpha)), and depleted antioxidant defenses were shown in stable cystic fibrosis (CF) patients. The plasma fatty acid status of CF patients was linked to oxidative stress after respiratory exacerbations.


OBJECTIVE
We examined changes in plasma 8-iso-PGF(2)(alpha), antioxidant defenses, plasma fatty acid status, and clinical markers resulting from short-term antioxidant supplementation.


METHODS
Forty-six CF patients were randomly assigned to either group A [low dose of supplement (10 mg vitamin E and 500 micro g vitamin A)] or group B [high dose of supplement (200 mg vitamin E, 300 mg vitamin C, 25 mg beta-carotene, 90 micro g Se, and 500 micro g vitamin A)]. Plasma concentrations of 8-iso-PGF(2)(alpha), vitamins E and C, beta-carotene, zinc, selenium, and copper; plasma fatty acid composition; erythrocyte glutathione peroxidase (EC 1.11.1.9) and superoxide dismutase (EC 1.15.1.1) activities; lung function; and dietary intake were measured before and after 8 wk of supplementation.


RESULTS
Antioxidant defenses in group B improved, whereas those in group A did not: in groups B and A, the mean (+/- SEM) changes (Delta) in vitamin E were 10.6 +/- 1.5 and -1.9 +/- 0.9 micro mol/L, respectively (P < 0.001), (Delta)beta-carotene were 0.1 +/- 0.04 and -0.01 +/- 0.02 micro mol/L, respectively (P = 0.007), (Delta)selenium were 0.51 +/- 0.10 and -0.09 +/- 0.04 micro mol/L, respectively (P < 0.001), and (Delta)glutathione peroxidase activity were 1.3 +/- 0.3 and -0.3 +/- 0.6 U/g hemoglobin, respectively (P = 0.016). There were no significant differences between the groups in Delta8-iso-PGF(2)(alpha), (Delta)vitamin C, (Delta)fatty acid composition, (Delta)superoxide dismutase activity, (Delta)lung function, or (Delta)white cell count. Within group B, (Delta)beta-carotene correlated with (Delta)percentage of forced vital capacity (r = 0.586, P = 0.005), (Delta)selenium correlated with (Delta)percentage of forced expiratory volume in 1 s (r = 0.440, P = 0.046), and (Delta)plasma fatty acid concentrations correlated with (Delta)percentage of forced expiratory volume in 1 s (r = 0.583, P = 0.006) and Delta8-iso-PGF(2)(alpha) (r = 0.538, P = 0.010).


CONCLUSIONS
Whereas increased beta-carotene, selenium, and fatty acid concentrations are linked to improved lung function, increased plasma fatty acid concentrations are linked to oxidative stress. If oxidative stress is deemed to be important to the clinical outcome of CF patients, means of reducing oxidative stress while maintaining a high-fat, high-energy diet must be investigated.
Wood
Lisa G
LG
Discipline of Nutrition and Dietetics, Faculty of Health, University of Newcastle, Callaghan, NSW, Australia.
Fitzgerald
Dominic A
DA
Lee
Alexander K
AK
Garg
Manohar L
ML
D000975:Antioxidants / Q000008:administration & dosage / Q000627:therapeutic use*; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000627:therapeutic use; D002648:Child; D003550:Cystic Fibrosis / Q000097:blood / Q000188:drug therapy* / Q000201:enzymology; D015930:Diet Records; D015232:Dinoprostone / Q000031:analogs & derivatives* / Q000097:blood*; D004311:Double-Blind Method; D005227:Fatty Acids / Q000097:blood*; D005260:Female; D006801:Humans; D028421:Isoprostanes / Q000097:blood*; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects*; D012129:Respiratory Function Tests; D012645:Selenomethionine / Q000008:administration & dosage / Q000627:therapeutic use; D014801:Vitamin A / Q000008:administration & dosage / Q000627:therapeutic use; D014810:Vitamin E / Q000008:administration & dosage / Q000627:therapeutic use
D000975:Antioxidants; D005227:Fatty Acids; D028421:Isoprostanes; D014801:Vitamin A; D014810:Vitamin E; D012645:Selenomethionine; D015232:Dinoprostone; D001205:Ascorbic Acid; C011987:8-isoprostaglandin E2