Wendy Wolfson
RedwoodAge.com
Since the 1940s, medical researchers have known that Eskimos who eat lots of fish have fewer heart problems.
Now there's fresh evidence fish oil can help the rest of us, including those with no history of heart disease.
A broad review of multiple studies suggests that fish oil is good for everyone, whether it comes from salmon, tuna, sardines, herring, and oysters, fish oil supplements or cod liver oil.
"There are no large randomized trials in healthy people but epidemiological data supports that those who eat more fish have lower serious heart disease," said Dr. Carl J. Lavie, the lead author for a research team that reviewed data from 30 years of studies involving fish oil that is high in omega-3 polyunsaturated fatty acids (PUFAs).
Humans don't naturally produce PUFAs but they can get fatty acids like eicosapentaenic acid (EPA) and docosahexanenoic acid (DHA) from oily fish.
The researchers concentrated on four randomized trials of 40,000 people who had experienced heart attacks or heart failure. All received EPA supplements, with or without DHA.
The level of protection varied for conditions such as atrial fibrillation and congestive heart failure, but heart patients who took PUFAs showed as much as a 30 percent reduction in deaths.
Some studies showed that "both eating more fish as well as having higher blood levels of EPA/DHA protect against sudden cardiac death," said Lavie, who is the medical director for Cardiac Rehabilitation and Prevention at Ochsner Heart and Vascular Institute in New Orleans. The review was published in the Jourrnal of the American College of Cardiology.
The Eskimo Factor
In the 1940's, researchers noticed that Inuits in Greenland who ate whale,
seal and fish but few complex carbohydrates and vegetables had a surprisingly
low rate of heart disease compared to Danes. Over the years, numerous studies
indicated that omega-3 PUFAs could help protect against a host of cardiovascular
problems, including heart attacks, arteriosclerosis, or atrial fibrillation,
even death from heart failure.
Not all the studies Lavie and his colleagues examined showed clear benefits. In one recent study of people who had heart attacks but were considered low risk, omega-3 PUFAs didn't seem to confer additional benefit on top of the aggressive, modern treatments they already were receiving. However these patients were only followed for one year. Another trial of heart failure patients already receiving optimal standard therapy only showed a modest 8 to 9 percent reduction in cardiovascular events.
The American Heart Association already recommends that healthy people take 500 mg of EPA and DHA daily, or eat two oily fish meals a week. People with coronary heart disease or congestive heart failure should take at least 800 to 1000 mg a day.
Fishy Burps
The researchers recommend that the these recommendations should also apply to
people with heart failure. They suggest further randomized studies to determine
the optimal dosing of EPA to DHA for healthy people.
One worry about eating more fish is the level of contaminants and methyl mercury in some species. However, because mercury binds to protein, it will stay in the muscle of the fish and not contaminate fish oil. And salmon, sardines, trout, oysters and herring are typically low in mercury.
Fish oil supplements are cheap. About the worst side effects they can cause are upset stomach, nausea and "fishy burps."
