Two Schools of Thought on Fish Oil: Can Supplements Guard the Heart?
BOSTON — Drug companies are going into the oil business--fish oil, that is.
Within the last few months, the subject has slid unctuously from the medical journals into network television ads. Suddenly, fish oil is hot. If the craze continues the way the marketers hope, fish oil tablets will join fiber, calcium and all things natural as an American dietary obsession.
Fish oil supplements have long been available, but the business changed dramatically last fall, when two big pharmaceutical firms, Squibb and Warner-Lambert, began nationwide ad campaigns to put their new brands of fish oil on everyone’s table.
The advertising is sprinkled with caveats and stresses the importance of a good diet, but it implies that people who take half a dozen or so fish oil tablets each day will reduce their risk of heart disease.
“We believe it absolutely does good,” says Marshall Molloy, a Warner-Lambert spokesman. “There’s no doubt in our minds about that. We think that it has been proved beyond a shadow of a doubt.”
In the minds of many nutrition experts , however, there is plenty of doubt.
‘Snake Oil’ Analogy
“Fish oil or snake oil?” asks Dr. Garret A. FitzGerald of Vanderbilt University in Nashville, Tenn. He and several other researchers say there is no evidence that ordinary people will be any healthier for taking a daily dose of fish oil.
The American Heart Assn. has long nagged Americans to eat wisely to save their hearts, but it, too, is unconvinced about the powers now claimed for fish oil.
“The safety and effectiveness of fish oil pills have not been proven,” says the association’s Howard Lewis. “We don’t recommend that people supplement their diets with these preparations. We have suggested since 1961, and continue to suggest, that people get their fish oil the old-fashioned way, and that’s by eating fish.”
Though there is no hard evidence that longtime consumption of fish oil supplements is harmful, the issue has not been settled. In fact, some of the same data used to laud its benefits can also be cited to point out its potential side effects.
Even if the fish oil fad doesn’t make people sick, it will make them a little poorer. Dr. Alexander Leaf of Massachusetts General Hospital notes that fish oil costs $300 a ton in bulk, but when bought by the bottle, it becomes a whole lot more expensive.
Expensive as a Supplement
Prices vary, depending on the brand and quantity purchased, but a single capsule generally costs between 9 cents and 25 cents. That is roughly between $81,000 and $224,000 a ton. The drug companies recommend that people take two with each meal, and that would cost about $200 to $500 a year.
Leaf is among those who believe that fish oil may be of some benefit in preventing heart disease, but he says that more research is needed.
“The evidence is growing increasingly strong,” he says, “that these substances probably are going to have a beneficial effect on coronary artery disease.”
Those with a family history of heart attacks or dangerously high levels of cholesterol in the blood might benefit from the capsules, he says, but people should consult their doctors before 1952998777”I’m not at a point of recommending it for everyone.”
Not just any fish oil will do. Oil from fish livers, for instance, contains too much of vitamins A and D to be a practical supplement. The medical research is centered on omega-3 fatty acids, found most plentifully in cold-water ocean fish such as salmon and mackerel. The fish oil tablets contain 300 or 500 milligrams of omega-3 fatty acids, depending on the brand.
Eating Fish Preferred
Scientists have only recently taken an interest in the health effects of this substance. In one version of its advertising to physicians, Warner-Lambert backs up its claims by naming 48 scientific reports on the subject. Seven of those papers were co-written by Dr. William E. Connor of Oregon Health Sciences University, who is one of the leading researchers in the young field. He does not endorse the supplements.
“The omega-3 fatty acids that one wants from the supplements are contained in fish,” says Connor. “And that would be the more logical way to get them, for the average citizen.”
Another researcher named in the ad, Dr. John A. Glomset of the University of Washington, is also dubious: “I believe we ought to know more about what we are doing before we charge out and give people supplements. What we know about these fatty acids is so limited.”
What the scientists do know comes from comparisons of large groups of people with different diets, as well as experiments with people and animals. The results add up to an impressive circumstantial indication that something in fish is good for people’s hearts.
Scientists say it appears that fish protects the heart by lowering the amount of blood fat, which can cause hardening of the arteries, and by slowing clotting time. What is still not clear is whether omega-3 fatty acids alone will do the trick, and, if they do, how much people need to take.
Eskimo Studies Cited
One of the first hints of fish’s benefits came from medical studies comparing Greenland Eskimos and Danes. Researchers noticed that there was strikingly less heart disease among the Eskimos. Of course, there are many differences in the lives and diets of Eskimos and Europeans, but scientists eventually concentrated on the large amount of fish in the Eskimo diet as a potential explanation.
Although Eskimos are shown in some of the fish oil ads, people who take the supplements won’t get nearly as much of this nutrient as the average fish-eating Eskimo. Vanderbilt’s FitzGerald said that people would have to take 50 tablets a day--something the drug companies certainly don’t suggest--to match the Eskimo diet.
FitzGerald also notes that Eskimos run an above-average risk of having strokes. Is fish oil the reason? No one knows, but FitzGerald said, “The very same sets of data that show the incidence of (heart attacks) in Greenland Eskimos is lower than that in European Danes show that the incidence of stroke (among Eskimos) is higher.”
More evidence in favor of fish oil comes from comparisons of fish eaters and fish haters who live in the same culture. The results are not all the same, but one report published two years ago suggested that eating fish once or twice a week would help prevent heart disease.
Substitution May Be Key
What these people aren’t eating, however, may be as important as what they eat. People who eat lots of fish are going to be eating little meat, and cutting out this source of saturated fat could play an important role in keeping them healthy.
