Potential effects of omega-3 fatty acids on anemia and inflammatory markers in maintenance hemodialysis patients

Abstract

BackgroundAnemia is a common complication among hemodialysis (HD) patients. Although intravenous iron and erythropoiesis-stimulating agents revolutionized anemia treatment, about 10% of HD patients show suboptimal response to these agents. Systemic inflammation and increased serum hepcidin level may contribute to this hyporesponsiveness. Considering the anti-inflammatory properties of omega-3 fatty acids, this study aimed to evaluate potential role of these fatty acids in improving anemia and inflammation of chronic HD patients.MethodsIn this randomized, placebo-controlled trial, 54 adult patients with HD duration of at least 3 months were randomized to ingest 1800 mg of either omega-3 fatty acids or matching placebo per day for 4 months. Anemia parameters including blood hemoglobin, serum iron, transferrin saturation (TSAT), erythropoietin resistance index, and required dose of intravenous iron and erythropoietin, and serum concentrations of inflammatory/anti-inflammatory markers including interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-10, C-reactive protein (CRP), hepcidin, ferritin, intact parathyroid hormone (iPTH), and ratios of IL-10 to IL-6 and IL-10 to TNF-α were measured at baseline and after 4 months of the intervention.Results45 subjects (25 in the omega-3 and 20 in the placebo group) completed the study. No significant changes were observed in blood hemoglobin, serum iron, TSAT, and required dose of intravenous iron in either within or between group comparisons. Additionally, erythropoietin resistance index as well as required dose of intravenous erythropoietin showed no significant change in the omega-3 group compared to the placebo group. Although a relative alleviation in inflammatory state appeared in the omega-3 group, the mean differences of inflammatory and anti-inflammatory markers between the two groups did not reach statistically significant level except for IL-10-to-IL-6 ratio and serum ferritin level which showed significant changes in favor of omega-3 treatment (P <0.001 and P = 0.003, respectively).ConclusionOmega-3 fatty acids relatively improved systemic inflammation of chronic HD patients without any prominent benefits on anemia. However, future well-designed studies on larger number of patients may determine utility of omega-3 fatty acids in HD patients with respect to inflammation and anemia.

Effects of flaxseed oil on blood hepcidin and hematologic factors in hemodialysis patients

“…The effect of flaxseed oil consumption on the reduction of serum hepcidin in HD patients may be due to a decrease in inflammation. 16 The disagreement of Gharekhani et al's findings with those of our study may be due to the administration of a lower dose of omega-3 fatty acids. Some studies have shown that hepcidin synthesis in liver is associated with inflammation.…”

“…However, few studies have been conducted on the effects of marine omega-3 fatty acids on hematologic factors in HD patients. [12][13][14][15][16] These disagreements may be due to the fact that marine omega-3 fatty acids had no effect on inflammation in these studies, [13][14][15][16] therefore, serum hepcidin did not reduce 16 and consequently an improvement in hematologic factors was not observed in these studies. 10 In their study, a significant reduction was observed in serum concentration of inflammatory cytokines and this may be a cause of increased hemoglobin.…”

“…The minimum sample size estimated for each group was 16 at a power (1-b) of 80% and a 5 0.05 for a two-arm parallel study with two-tailed testing to detect a difference of 1.4 g/dL in blood hemoglobin concentration with a pooled standard deviation of 1.41 g/dL, obtained from the study by Gharekhani et al 16 Thirty-eight HD patients were selected using convenience sampling from the HD units at Taleghani and Modares hospitals in Tehran, Iran. The minimum sample size estimated for each group was 16 at a power (1-b) of 80% and a 5 0.05 for a two-arm parallel study with two-tailed testing to detect a difference of 1.4 g/dL in blood hemoglobin concentration with a pooled standard deviation of 1.41 g/dL, obtained from the study by Gharekhani et al 16 Thirty-eight HD patients were selected using convenience sampling from the HD units at Taleghani and Modares hospitals in Tehran, Iran.…”

“…8,9 According to the available literature, no study has been performed on the effects of flaxseed oil on blood hepcidin and hematologic factors in HD patients. [12][13][14][15][16] Therefore, the present study was designed to investigate the effects of flaxseed oil on blood hepcidin and hematologic factors in HD patients. The findings of these studies have been contradictory.…”

“…Some of these studies indicated that omega-3 fatty acids increased hemoglobin 10 and decreased erythropoietin requirement, 11 whereas other studies did not find these effects in HD patients. [12][13][14][15][16] Therefore, the present study was designed to investigate the effects of flaxseed oil on blood hepcidin and hematologic factors in HD patients.…”