Background: Supplementation of the diet with eicosapentaenoic acid and docosahexaenoic acid, the main long-chain omega-3 fatty acids in cell membranes, may have beneficial effects in patients with cystic fibrosis.
Methods: A prospective study involving 30 patients and 20 control subjects was carried out; eicosapentaenoic plus docosahexaenoic acid was equal to 1.3% of caloric intake in the cystic fibrosis patients. Our present study included the evaluation of eicosapentaenoic and docosahexaenoic acid incorporation into erythrocyte membranes and biological and clinical effects in response to long-term (8 months) supplementation with fish oil as a source of eicosapentaenoic and docosahexaenoic acids in patients with cystic fibrosis.
Results: Baseline erythrocyte membrane fatty acids showed low levels of linoleic acid and eicosapentaenoic acid and mild elevation of 18:3n6, but similar docosahexanoic acid and other fatty acids in cystic fibrosis patients compared with controls. Fish oil supplementation led to a 1.7-fold (p < .05) and 1.3-fold (not significant) increase of eicosapentaenoic acid in erythrocyte membrane phospholipids after 4 and 8 months of supplementation, respectively, and to a 1.67-fold (p < .05) and 1.38-fold (p < .05) increase of docosahexanoic acid, respectively. Along with these changes, there was a progressive decrease of arachidonic acid (from 8.51 to 6.67 g/100 fatty acids at 4 months and 4.83 g/100 fatty acids at 8 months; p < .05) and an increase of linoleic acid (p < .05) in membrane phospholipids. Analysis of inflammatory markers showed a significant decrease of serum immunoglobulin G (IgG) and of alpha-1 antitrypsin (p < .05) concentrations. Pulmonary function testing showed mild but significant improvement of forced expiratory volume (FEV)-1 from 61% +/- 19% to 57% +/- 19% of predicted values (p < .05). The number of days of antibiotic therapy during the study period was markedly lower compared with the preceding 8-month period (392 versus 721 days; p < .05).
Conclusion: Long-term eicosapentaenoic plus docosahexanoic acid supplementation (8 months) has positive effects, such as decreasing inflammation, in cystic fibrosis.