Supplementation lowered the risk of major coronary events in hemodialysis patients.
CVD is the major cause of premature mortality in hemodialysis patients. There is some evidence to suggest that higher levels of n-3 fatty acid consumption than is typical in Western diets may reduce risk in the general population.
Surveys of the n-3 nutritional status of dialysis patients show that, like the general population, they are generally marginal or deficient, typically due to low consumption of fatty fish (Am J Kidney Dis. 2006;47:1064-1071).
The 2005 National Kidney Foundation Kidney Disease Outcomes Quality Initiative for Clinical Practice Guidelines for Cardiovascular Disease in Dialysis Patients recommended further research in the field. Several studies on n-3 fatty acids effect on CVD in patients have been completed since that report was released.
For example, Perunicic-Pekovic et al. (Nephrology. 2007;12:331-336) found that dialysis patients were deficient in the essential fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). They were generally mildly malnourished based on global nutritional assessment.
At baseline, n-3 fatty acid levels were negatively correlated with interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-a), markers of inflammatory status. Patients were supplemented with fish oil capsules containing 2.4 g EPA plus DHA for eight weeks. The supplement increased red blood cell membrane EPA and DHA significantly. Other nutritional markers also improved, including hemoglobin, albumin and HDL cholesterol. IL-6 and TNF-a decreased dramatically.
In a similar design, researchers at Aarhus University Hospital in Denmark supplemented dialysis patients with 2.4 g PUFA for eight weeks (J Renal Nutr. 2007;17:258-263). They determined that C-reactive protein (CRP) in granulocyte membranes was marginally decreased from 2.46 to 1.47 mg/L and remained unchanged (3.27 vs. 3.14 mg/L) in control patients ingesting olive oil. In another paper (J Renal Nutr. 2007;17:243-249), the same team reported that heart rate variability in 30 dialysis patients with documented CVD was not effected by 1.7 g n-3 fatty acid supplementation for eight weeks.
In a previous study (Clin J Am Soc Nephol. 2006:1:780-786), Svensson et al. randomly assigned 206 hemodialysis patients to either supplementation with 1.7 g n-3 fatty acids or the same amount of olive oil. The primary end point was a composite of total cardiovascular events in the two-year treatment period. During the trial, 121 of the patients reached the primary end point.
The n-3 fatty acids had no significant effect on either total cardiovascular events (62 vs. 59) or death (34 vs. 30). However, the researchers observed significant declines in the number of major coronary events in n-3 supplemented patients compared with controls (7 vs. 17).
Furthermore, n-3 supplementation was associated with a significant decrease in the number of new MIs (4 vs. 13). The authors hypothesized that earlier intervention or a larger dose of n-3 fatty acids might be more effective.