MONDAY, April 11, 2005 (HealthDay News) -- For older men and women, a dose of fish or soy oil a day could help keep the cardiologist away.
That's according to a new study which suggests that daily supplements of omega-3 fatty acids sourced from soy or fish quickly produces reductions in an elderly user's risk for sudden heart attack.
A research team from Atlanta, Boston and Mexico found that a key measure of healthy heartbeat function -- known as heart rate variability (HRV) -- improves quickly and significantly among those aged 60 and over who begin taking these supplements. Their report appears in the April issue of Chest.
HRV testing is a well-established screening tool used by cardiologists to assess the heart's electrical system -- helping to distinguish healthy heartbeat variations from potentially fatal heart rhythm abnormalities, such as arrhythmia.
"Although most people think that the heart beats like a clock, in reality our hearts have constant fine-tuning variations that you are not even aware of," explained study author Dr. Fernando Holguin, of Emory University School of Medicine, in Atlanta.
"The timing between heartbeats may all of a sudden be a little shorter or longer, and these adjustments are a very good thing," he stressed. "Those who have heart failure do not have those variations. And the fatty acids in the fish and soy oils increase these variations, which is clear evidence of having a healthier heart."
In 2001 and 2002, Holguin and his colleagues focused on the HRV levels of 52 male and female nursing home residents whose regular dietary intake of fish was assessed as "poor." All were over the age of 60, and none relied on a pacemaker or had a prior history of arrhythmia.
Before administering any supplements, the research team first tracked HRV levels among the patients every other day for two months. Over the next 11 weeks they gave half the group marine-based omega-3 fatty acid supplements, in the form of 2 grams of fish oil capsules per day. The other half received similar capsules containing plant-based fatty acids, at 2 grams of soy oil per day.
HRV measurements taken every other day throughout the supplement period demonstrated significant increases in healthy heart variations among all the patients, the researchers report.
Soy oil provoked the least amount of unwanted side effects, causing belching in just 16 percent of the soy capsule patients, compared with 41 percent of the fish capsule patients. As well, the soy oil capsules provoked nausea in only 8 percent of users, compared to almost 13 percent among fish capsule recipients.
Holguin and his team noted, however, that fish oil capsules seemed to provide the greater overall cardiac benefit. Those taking the fish oil capsules were quicker to improve their HRV levels than those taking the soy oil capsules, for example. And those ingesting fish oil experienced HRV increases within just three weeks, compared to eight weeks in those taking soy oil.
Similarly, the researchers also found that, of the two supplements, fish oil appeared to provoke HRV improvements across the widest spectrum of electrical impulses that control healthy heartbeat changes.
The Atlanta team concluded that -- in a much shorter period of time than was previously thought -- both types of omega-3 fatty acid supplements offer some protection against unhealthy heartbeat and related deadly heart attacks among elderly patients.
The research team expressed hope that supplementation could prove to be a key ingredient -- alongside exercise, stress management, weight loss and good sleeping habits -- in any lifestyle strategy aimed at preserving healthy heart functioning through the 'golden years.'
Hoguin cautioned, however, that further research is still needed, and no one should run to the nearest drug store to stock up on fish or soy oil.
"There's no simple answer," he said. "It's difficult to determine the perfect dose one would recommend for supplements. So, for now, I think at least consuming one meal of fish per week is probably the best thing to do to reap the benefits of omega-3."
He noted that a diet rich in omega-3 would include fatty fishes such as tuna and salmon, leafy green vegetables, and nuts such as almonds and walnuts.
Both Dr. Nieca Goldberg, chief of women's cardiac care at Lenox Hill Hospital in New York City, and Dr. David Jenkins, research chairman of nutrition and metabolism at the University of Toronto, concurred on the need to incorporate omega-3 fatty acids into daily meals. But both also agreed that making any firm supplement recommendations would be premature.
"This adds to the body of knowledge that omega-3s are very beneficial for the heart," Goldberg said. "But you always have to be careful about taking supplements, and always talk to your doctor about it." She noted that omega-3 can function as a natural blood thinner, and should not always be mixed with other blood thinners, such as aspirin.
It's a very interesting study, but one should view it with caution," Jenkins said. "While I don't want to seem negative, prior studies on fish oil have shown the benefit to be a marginal success. So much more data is needed before we come to any conclusion about supplements."
To learn more about heart disease, visit the American Heart Association.