Supplementation of hemodialysis patients with long chain fatty acids to reduce pruritus symptoms and maintain hematocrit
Abstract
The effect of supplementation with two sources of long chain fatty acids, fish oil (FO) and safflower oil (SO), on the production of leukotriene B 4 (LTB4) by the polymorphonuclear leukocytes (PMNL) and on pruritus symptoms in hemodialysis patients was examined in a prospective, double blind study. Patients of both sexes, age ≥20 years, with complaints of dry skin and pruritus were randomized into 3 groups to receive either daily supplements of 6 g ethyl ester of FO, SO, or no supplementation (control group) for 16 weeks. Following supplementation, the FO group had significantly higher composition of total n-3 fatty acids in red blood cell (RBC) membranes ( P = 0.0079), and a higher ratio of n-3 to n-6 fatty acids ( P = 0.0091) in comparison to the SO and control groups. There were non-significant decreases in LTB4 production by blood cells. FO-supplemented patients exhibited a decrease in the frequency of all of the symptoms of pruritus by the end of the study (P < 0.05), but this trend was not observed in the other treatment groups. Although this improvement was not statistically significant its clinical relevance may be important. The effects of supplementation on changes in RBC membrane fluidity, hematocrit, erythropoetin (EPO) dosage, oxidative burst activity of PMNL, and plasma vitamin E status were examined. Supplementation did not affect RBC membrane fluidity or oxidative burst activity in neutrophils or monocytes. However, a decline in hematocrit was observed in blood from SO group patients (P < 0.05), but this did not occur in patients supplemented with FO. These effects on hematocrit were mirrored by changes in the patients' EPO dosage required to maintain RBC numbers. Patients in the FO group maintained or even further reduced their EPO dosage levels, whereas one-third of the SO group participants were required to increase their dosages. Additionally, the mean plasma α-tocopherol concentrations were maintained in the FO group, but significantly reduced in the SO group (P = 0.0061). These results suggest that oxidative stress contributes to anemia in hemodialysis patients. Overall, the results of this study suggest that dietary FO supplementation produces a clinically important reduction in the severity of pruritus symptoms, but its affects on hematocrit are uncertain and require further research with a larger sample size.
Degree
Ph.D.
Advisors
Peck, Purdue University.
Subject Area
Nutrition
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