The effects of fish oil supplementation on markers of inflammation in chronic kidney disease patients.

OBJECTIVE

One prevalent characteristic of all stages of chronic kidney disease (CKD) is excessive production of proinflammatory cytokines. Fish oil (FO) supplementation has been reported to lower levels of proinflammatory cytokines. The benefits of FO for an extensive range of populations and a variety of health concerns are apparent, yet the anti-inflammatory benefits for nondialysis CKD patients are not as well documented. Therefore, the purpose of this study was to investigate the effects of the daily consumption of FO (1,400 mg eicosapentaenoic acid + 1,000 mg docosahexaenoic acid) on interleukin 1β (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α) for 8 weeks in nondialysis CKD patients.

DESIGN, SETTING, AND SUBJECTS: In this double-blind, randomized, placebo-controlled intervention, the effect of 8 weeks of FO administration on IL-1β, IL-6, and TNF-α levels in nondialysis CKD patients were evaluated.

INTERVENTION

Thirty-one nondialysis CKD patients (17 = FO; 14 = placebo) randomly received either FO dietary supplementation 2.4 g/day (1,400 mg eicosapentaenoic acid + 1,000 mg docosahexaenoic acid) or placebo (safflower oil) for 8 weeks.

MAIN OUTCOME MEASURES

IL-1β, IL-6, and TNF-α were all measured as markers of inflammation.

RESULTS

One-way analysis of variance revealed no significant differences in IL-6 (P = .06), IL-1β (P = .18), and TNF-α (P = .20) between groups in pretest values. Additionally, no pretest differences existed between groups for age (P = .549), weight (P = .324), waist circumference (P = .086), gender (P = .591), and ethnicity (P = .875). Covariance was calculated using compliance, age, gender, ethnicity, body weight, and waist circumference as covariates. No significant differences were discovered between groups after FO supplementation for IL-6 (P = .453) and TNF-α (P = .242). A significant difference was discovered for IL-1β (P = .050) with lower levels in the FO group.

CONCLUSIONS

The results of this study are in agreement with some previous studies that suggest that FO supplementation has no effect on plasma proinflammatory cytokines TNF-α or IL-6, but does have an effect on IL-1β in nondialysis CKD patients.