A simple daily fish oil supplement could prevent thousands of heart attacks and strokes among the more than 516,000 people undergoing dialysis in the United States, according to new research showing the treatment cut cardiovascular events nearly in half.
The PISCES trial, published on Nov. 7 in the New England Journal of Medicine, was conducted at 26 sites in Canada and Australia and involved 1,228 adults receiving routine dialysis—a treatment for severe kidney failure—for approximately 3 1/2 years.
The findings are particularly significant given that dialysis patients face exceptionally high cardiovascular risk, with mortality due to cardiovascular disease 20 times higher than that of the general population.
A large, multicenter, randomized controlled trial that found roughly a 50 percent reduction in serious cardiovascular events over several years in a high-risk population—with consistent effects and no safety issues—”is rare and important,” Dr. Carolyn Lam, co-founder of Us2.ai, a startup that uses artificial intelligence and ultrasound scans to fight heart disease, who was not involved in the study, told The Epoch Times.
Among hemodialysis patients, stroke is the most frequent cardiovascular-related event, affecting about 26 percent of patients, followed by cardiac disease.
The Treatment: 4 Capsules Daily
Participants were randomly assigned to receive either fish oil capsules containing omega-3 fatty acids or a placebo made of corn oil, with neither the patients nor the researchers knowing who was in which group.
Those in the treatment group took four capsules daily, providing a total of 1.6 grams of eicosapentaenoic acid or EPA and 0.8 grams of docosahexaenoic acid or DHA—the key omega-3 fatty acids in fish oil. Blood tests confirmed that participants in the fish oil group had increased levels of these fatty acids in their blood, indicating good adherence to the regimen.
The results showed that fish oil users experienced 43 percent fewer serious cardiovascular events—including heart attacks, strokes, sudden cardiac death, and limb amputations due to vascular disease—compared with the placebo group.
Safety monitoring showed no increase in bleeding risk, which had been a concern with omega-3 supplements, and adverse events were similar across both groups.
“We did not see any differences in adverse effects between the fish oil group and the placebo group,” study author Dr. Charmaine Lok, professor of medicine at the University of Toronto and senior scientist at the Toronto General Hospital Research Institute, told The Epoch Times.
Dr. Andrew Moses, a nephrologist at Northwell Health’s Lenox Hill Hospital in New York, who was not involved in the study, called the data “very exciting,” noting that only three patients need to be treated to prevent one cardiovascular event over 3 1/2 years.
“So even with the limitations, if there are three patients that could qualify for and tolerate high-dose omega-3s, then you may have prevented a negative outcome, which is pretty amazing,” Moses said.
Why Fish Oil May Work for Dialysis Patients
Omega-3 fatty acids may protect the heart by reducing inflammation, preventing abnormal heart rhythms (arrhythmias), and improving blood vessel function. Patients on dialysis tend to have lower levels of these beneficial fats, which might explain why supplementation had such a positive effect.
Lok said her hypothesis is that omega-3s slow the progression of cardiovascular disease and reduce sudden health problems through their possible effects in preventing blood clots, irregular heartbeats, and stabilizing plaque.
Dialysis patients are at an especially high risk of cardiovascular events due to a pro-inflammatory and pro-arrhythmic environment caused by the dialysis process itself. During dialysis, rapid shifts in fluid and electrolyte levels can lead to heart stress and irregular rhythms, which omega-3s may help stabilize by inhibiting certain electrical currents in heart cells.
The study’s findings align with previous research suggesting that higher blood levels of omega-3s are associated with lower cardiovascular risk.
Important Caveats and Next Steps
Researchers noted that the dosage of fish oil used was higher than 1 gram per day, which has been shown to be more effective in other research. The capsules used also contained a specific formulation of ethyl ester-based omega-3s—a concentrated, processed form of fish oil—which might have contributed to their effectiveness.
Lok cautioned that patients should ask their doctors about the right capsules to take and how to properly take them, emphasizing that the trial showed “specific fish oil capsules were safe and reduced the rate of cardiovascular events.”
Moses noted that the trial was funded by the manufacturer of Vascepa, a high-dose omega-3 fatty acid product, introducing potential bias. “That being said, the data is still amazingly good and should be replicated to ensure it is true,” he said.
Other limitations include that many participants were not on aggressive cardiovascular therapy, and that the results might not apply to patients not on dialysis.
Moses noted that many dialysis patients take anticoagulant or antiplatelet drugs, which may have excluded a significant portion of potential participants.
The study excluded participants if they took more than two anticoagulant drugs, according to the study protocol.
The researchers emphasized that further studies are needed to determine optimal dosing and long-term safety, but the results suggest that fish oil could be an effective intervention to reduce cardiovascular morbidity and mortality among dialysis patients.
