The latest analysis, which reviewed just over a dozen smaller studies, found that taking the supplements – or not – made little difference in whether 20,000 chronic heart disease patients suffered heart attacks or strokes.
But don’t toss your fish pills just yet, says URMC cardiologist Dr. Robert Block. There’s more to consider. Below, he helps make sense of the latest science – and its short-comings.
Scripts: Historically, have cardiologists advised cardiac patients (say, those with high cholesterol) to take fish-oil capsules – and if so, based on what research?
Block: It’s important to note that a fair number of older studies – many of which were conducted before the mainstream adoption of today’s aggressive medicines, like statins and beta-blockers – were quite conclusive. They suggested fish oil supplements indeed played an important role of protecting patients with heart failure.
Take the GISSI (Gruppo Italiano per lo Studio dells Sopravvivenza nell’Infarto Miocardico) trial, for instance, which found that these pills lowered the risk of fatal cardiovascular events by 10 percent for cardiac patients. So, conceivably, it could be that more recent trials (in which the bulk of patients were already taking powerful medications) might not accurately appreciate the role that fish oil actually plays – especially for people never diagnosed with heart disease to begin with.
To that end, many cardiologists do recommend fish oil supplements – or better yet, eating more real fish – since the known side-effects (other than the occasional potential for a fishy burp!) are negligible. What’s more, fish oil does not interact with other medications – a big problem we see with many prescription drugs.
Scripts: Some people assume that “supplements,” in general, are just as good of a substitute for consuming the real food. But does this study possibly suggest that the part of the benefit of fish oil, in its most natural form (that is, in actual fish!), comes because fish are eaten in place of other less-healthy meats?
Block: Certainly, fish are a wonderful dietary staple. The health benefits are well-documented, and the most current, 2010 Dietary Guidelines for Americans advise all of us (even pregnant women) to eat more servings of fish. And, even while the data supporting fish oil supplements is less cut -and-dried, the American Heart Association nevertheless maintains an official recommendation that patients with the metabolic syndrome (pre-diabetes) should eat more fish – or take fish-oil supplements.
But certainly, you raise a fair point – consuming nutrient-rich foods in their natural form is important, because theoretically, because it represents a smart trade-off: Chances are good that your fish-based meals are replacing other less-good-for-you protein sources, like pork or red meats.
Scripts: Many of the studies wrapped into this latest analysis didn’t follow patients for the long-term. Isn’t it possible that, especially for patients who have not developed heart disease, there still is some longitudinal benefit from supplements?
Block: Absolutely! This is a major limitation of the study, and a point that’s getting a good deal of press attention. When it comes to preventive cardiology, we’re keenly focused on long-term health risks – looking ahead 30 to 50 years, rather than shorter periods like these trials are studying.
What’s more, sample size really matters – and is often overlooked by the public. Frankly, many of the studies wrapped into this most recent meta-analysis (a “study of studies”) were probably too small to detect the modest but important risk-reduction role supplements likely play.
Scripts: So bigger, longer-term studies are warranted – that makes sense. But, are all fish-oil supplements created equal?
Block: Supplements definitely vary in quality – and of course, cost. Take Lovaza, for instance; it’s an FDA-approved prescription drug composed of about 85 percent EPA and DHA, the most important fatty acids in fish, and is commonly prescribed for diabetics and obese folks with high triglycerides (a major cause of pancreatitis—a very serious health issue).
On the other hand, cheaper, over-the-counter options generally pack only 30 to 60 percent EPA and DHA. Many people at high-risk for cardiovascular disease take them (including me) because they feel better doing so, and are banking on their potential for longer-term health benefits.
Of course, it’s important to note that improving heart health isn’t the only thing omega-3 fatty acids have been lauded for. Other studies have found fish-oil supplements to reduce joint pain and stiffness, boost the effects of anti-depressants, and play an important, brain-building role in the womb (aiding babies’ neurological and visual development). So, it’s important that we take new studies in stride, looking closely at their design and asking how each fits into the bigger picture of all the science that’s gone before – as well as the science that’s currently underway.
Dr. Block specializes in the care of patients with high blood cholesterol levels. If you’ve been diagnosed with unhealthy cholesterol levels, and are you looking for help getting them under control, call URMC’s Lipid Clinic at URMC at (585) 341-7700.