Review of the effects of omega-3 supplementation in dialysis patients

Chronic dialysis patients experience a host of conditions that limit quality and length of life, and recent therapeutic strategies have had only modest success in ameliorating many of these problems. By mediating cell membrane function and structure and the synthesis of lipid mediators such as eicosanoids, omega-3 fatty acids may offer dialysis patients a host of therapeutic benefits. Omega-3 fatty acids are derived primarily from dietary sources, and cold-water fish is the main source of eicosapentanoic and docosahexanoic acids, the two major bioactive omega-3 fatty acids. Studies of omega-3 supplementation in dialysis patients describe salutary effects on triglyceride levels, dialysis access patency, and perhaps uremic pruritus and oxidative stress. In contrast, the putative hematologic, antihypertensive, anti-inflammatory, and antiarrhythmic effects are not as well documented. Adverse effects generally have been limited to gastrointestinal complaints. Unfortunately, the preponderance of published studies are characterized by suboptimal study design, small sample sizes, supraphysiologic omega-3 doses that may be difficult to consume for extended periods, little long-term follow-up, and a lack of confirmation of compliance. Not surprising, the 2005 National Kidney Foundation Kidney Disease Outcomes Quality Initiative Clinical Practice Guidelines for Cardiovascular Disease in Dialysis Patients recommend further research in this field. In summary, although preliminary data suggest that omega-3 fatty acids may have clinical benefits, formal recommendations encouraging omega-3 supplementation of dialysis patients are premature until long-term and adverse effects are better defined.