Fish oil capsules, promoted as being capable of lowering cholesterol levels, may actually cause harmful side effects including internal bleeding in some individuals.
The increasingly popular dietary supplements contain concentrations of omega 3s, a compound in fish that is thought to improve cardiovascular functions.
Medical research has shown that omega 3s can facilitate the flow of blood to the heart by reducing accumulations of fat in arteries. Studies have also found that the substance decreases those cholesterol levels--low density lipoproteins--which are associated with coronary disease.
However, these same anti-clotting properties can also aggravate bleeding due to illnesses such as gastritis, kidney diseases, diverticulosis and other gastrointestinal disorders, according to Ann L. Gerhardt MD, a professor of internal medicine at UC Davis.
"If you have a tendency to bleed (as a result of illness or injury), or if there is tissue damage that might lead you to hemorrhage, you will be far worse off by consuming these products than you would be otherwise," said Gerhardt, who also serves as co-director of the UC Davis School of Medicine's Lipid Disorders and Atherosclerosis Prevention Clinic. "All fish oil capsules can cause trouble with clotting."
Upon ingestion, the fatty acids present in the fish oils are transformed into substances, known as prostaglandins, which affect the body's ability to clot, both from internal and external injuries, Gerhardt said.
Virtually anyone who is considering taking fish oil capsules should first consult with a physician, Gerhardt said. And those who do consume the tablets should be aware that the risk of hemorrhaging is doubled if they also consume aspirins, which act in a similar manner.
Gerhardt's warning was echoed by Wayne R. Bidlack Ph.D., associate professor of pharmacology and nutrition at the University of Southern California.
"I would tell consumers that (fish oil capsules) are an untested therapeutic agent and their benefits in terms of coronary disease is unproven. If you already have a bleeding problem, then the same warning that applies to aspirin holds for fish oils because the bleeding will continue," Bidlack said. "I'm totally skeptical of the efficacy of treating atherosclerosis with fish oils: it's a totally untested product that, therefore, increases the risk to the patient."
A spokesman for Warner-Lambert Co., which produces Promega, the nation's best-selling fish oil capsule, said that he was familiar with Gerhardt's claims, but saw no reason for concern.
Medical researchers who recently reviewed fish oil capsule usage found "no evidence of abnormal increases in bleeding," according to Marshall Molloy, of the Morris Plains, N.J.,-based firm. "Our position all along is that there is no more risk in taking Promega, on balance, than in taking an aspirin a day."
Promega, with annual retail sales in excess of $12 million, was introduced in 1986. Similar products have been sold for years in health food stores, but Warner-Lambert was the first to nationally distribute and advertise a supplement, Molloy said. It's also manufactured entirely from fish oil, a standard that has not been universally adopted by all other brands.
In fact, Gerhardt cautions that consumers should make sure that the brand of fish oil capsule selected for use is pure. With the proliferation of the products over the past few years there have been several instances where tablets actually contained cholesterol, she said.
"Some preparations are not as pure as others. Those made from the entire fish--including the fish liver--will contain cholesterol . . . which can accumulate in the body of the person that is taking them," she said. "People should be aware."
Contamination Overseas--Food contamination presents serious health and economic problems for many developing nations, according to a recent article in Ceres magazine.
"Rapid urban growth and industrialization (in Third World countries) are leading to increased and inadequately monitored use of chemicals in agriculture and microbiological contamination caused by poor food processing," the report, a portion of which was reprinted in World Development Forum, stated.
The problem stems from the fact that food safety is a low priority in many of these countries and, as a result, "less sophisticated controls over food handling and more lax restrictions concerning chemical additives, adulterants and labeling" are commonplace, according to the report.
During the past year, this view has been shared by U.S. regulatory officials who have identified imported products as a significant source of food-borne illness in this country.
In response, the magazine said that the United States is currently detaining millions of dollars of food imports at ports of entry each year.
Loss of just such much-needed foreign revenue is likely to motivate those countries troubled with contamination to increase processing standards. But any such change is likely to take time, World Development Forum concludes.