Imagine going to your favorite fast-food restaurant and ordering a blubber-packed whaleburger on a sesame seed bun instead of a flame-broiled burger. Sound unhealthy? Maybe not.
Like some types of fish, whales and other marine mammals are high in a type of fat called omega-3 polyunsaturated fatty acids. Physicians working in the Arctic first began to uncover the heart-healthy benefits of omega-3’s when they puzzled over why the Inuit Eskimos—who regularly dined on a high-fat, high-cholesterol diet of whale, seal, and fish—rarely developed heart disease.
Later, studies in Greenland confirmed that the rate of heart disease among the Inuits was much lower than that of Westerners, even though both diets provided similar amounts of fat.
The difference, scientists concluded, was due to the source of fat in the two diets. Whereas Westerners get their fat from land animals and plants, the Inuits get most of theirs from marine mammals and fish. Since this discovery, much research has focused on the role of the omega-3’s and their impact on heart disease and other ailments.
Not All Fats Are Created Equal
Our bodies make most of the fat they need from the carbon, hydrogen, and oxygen atoms that are found in food. But they don’t have any way to create omega-3’s and another type of fatty acids, omega-6’s. Both of these belong to a category called essential fats, and they come only from certain foods.
There are two varieties of omega-3’s. The first is made up of eico sapentaenoic acid (EPA) and docosahexaenoic acid (DHA). To get your fill of these, feast on fatty fish such as salmon and mackerel.
The second type of omega-3’s is alpha-linolenic acid (ALA), which is provided by plant foods. Once it’s inside your body, some ALA can be converted into EPA and DHA. Sources high in ALA include flaxseed oil and canola oil.
The other essential fat that the body can’t manufacture is known as omega-6, or linoleic acid. While omega-6 oils are vital to our health, we may be getting too much in our diets. Most vegetable oils today have very high amounts of omega-6’s but not enough omega-3’s, and that kind of imbalance could turn into risky business for our bodies.
Scientists think that in the diets of our ancestors, the ratio of the two types was nearly 1 to 1. Today, the omega-6/omega-3 ratio is about 10 to 1. When linoleic acid dominates too heavily over omega-3’s, it may jeopardize our health.
Fish Oils to the Rescue
The body uses both types of omegas to create a variety of short-lived, hormonelike substances called eicosanoids. These substances perform many functions, such as regulating blood pressure, controlling important aspects of the reproductive cycle, and inducing blood clotting, among other things.
SUPPLEMENTSNAPSHOT
| Fish Oil Supplement forms: Omega-3 fatty acids, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). May help: Heart disease, angina, high blood pressure, high cholesterol, asthma, breast cancer, colon cancer, lupus, multiple sclerosis, rheumatoid arthritis, gout, migraines, prostate problems, and inflammation. Good food sources: Mackerel, salmon, herring, bluefish, albacore tuna, rainbow trout, and swordfish. Cautions and possible side effects: Increases bleeding time, possibly resulting in nosebleeds and easy bruising, and may cause upset stomach. Do not take if you have a bleeding disorder or uncontrolled high blood pressure, take anticoagulants (blood thinners) or use aspirin regularly, or are allergic to any kind of fish. Take fish oil, not fish-liver oil, which is high in vitamins A and D—vitamins that may be toxic in high amounts. People with diabetes should not take fish oil because of its high fat content. |
Prostaglandins, one of the better-known types of eicosanoids, have an effect on the brain, blood vessel walls, certain blood cells, and blood platelets. They are involved in regulating almost every body function, including those of the digestive, nervous, and reproductive systems. Prostaglandins also influence the ways in which blood vessels expand and contract, and they help manage blood clotting.
When an overabundance of prostaglandins and other eicosanoids is set loose in the body, the result may be excessive blood clotting and narrowing of the arteries. That’s where fish oils may act. EPA and DHA decrease the stickiness of the blood platelets involved in clotting, thus reducing the risk of a clot that could lead to a heart attack.
If omega-6’s dominate and omega-3’s are in short supply, eicosanoids can provoke inflammation, blood clots, and other problems. If omega-3’s are plentiful, eicosanoids have milder effects.
Heart-Healthy News
Let’s return to the Eskimos. Studies have revealed that their omega-3–rich diet results in lower blood cholesterol, lower triglycerides (another type of blood fat), lower LDL cholesterol (the "bad" type), increased HDL cholesterol (the "good" type), and lower rates of heart disease. These Eskimos also have prolonged bleeding times. Ominous though that sounds, it is actually something that heart disease researchers like to see, because it means that blood is thinner and therefore flows more smoothly.
There’s also evidence that fish consumption may make heart attacks less dangerous if they do happen. In one study, a number of men who had survived heart attacks went on a diet that was high in fish. Compared to male heart attack patients who just had normal diets, those in the fish-eating group were more likely to live longer.
How does fish oil help the heart? The omega-3’s in fish oil may reduce the risk or even the severity of heart disease by influencing several factors, including blood clotting and blood pressure. They may also reduce the risk that a person will have cardiac arrhythmia (irregular heartbeat).
When you eat foods that are high in omega-3’s, that valuable fish oil becomes incorporated into the cell membranes of platelets, making them less likely to clump together. In a way, fish oil acts like a very weak form of aspirin, which also has a good reputation as a heart disease preventive and, like fish oil, is believed to decrease the clumping of platelets.
Aid for Arthritis
Various studies have tested fish-oil treatments for the symptoms of rheumatoid arthritis, the kind of joint-attacking arthritis that can begin as early as childhood. Analyzing data from the 10 best-conducted trials to date, researchers concluded that taking fish-oil supplements for at least three months resulted in modest but positive improvements, mainly less morning stiffness and tender joints.
The amounts of fish-oil supplements used in most clinical studies are high—about 3,000 to 5,000 milligrams of omega-3’s daily. To get this much from your diet, you would have to eat at least 10 ounces of cooked rainbow trout. Most fish-oil supplements contain about 500 milligrams of omega-3 fatty acids in each 1,000-milligram capsule.
Benefits may come from smaller amounts of fish oil as well. In one study, women who ate two or more servings of broiled or baked fish a week had about half the risk of developing rheumatoid arthritis as women who ate only one serving.
Fish oil appears to ease rheumatoid arthritis and a variety of other inflammatory diseases by suppressing inflammation. While no one seems ready to proclaim fish oil a cure, at least one study has shown that it helps reduce or even eliminate the need for the nonsteroidal anti-inflammatory drugs that are most commonly prescribed for the disease.
An Ocean of Uses
Fish oil may even prove beneficial in preventing and treating certain cancers. In one study, researchers had 25 women with breast cancer eat a low-fat, high-fiber diet and take 10,000 milligrams of fish-oil supplements daily—far more than anyone would think of taking under normal circumstances. After three months, the omega-3 fatty acids stored in the women’s breasts increased. This is significant because animal studies have shown that omega-3’s delay the development of cancer and can inhibit tumor growth.
Despite the implications of this study, you should not try to take this large dosage of fish oil every day to combat breast cancer or the risk of it. Such high amounts should be taken only under a doctor’s dir ection.
| What’s in a Name? Fish-oil supplements are sold under many names, from the obvious, such as fish oil or omega-3, to the not-so-obvious, including supplements that feature docosahexaenoic acid (DHA) or eicosapentaenoic acid (EPA) prominently in the name. Chances are, most fish-oil supplements include a mixture of EPA and DHA, no matter what they’re called. Usually, a closer look at the label will tell you. It’s not yet clear whether DHA and EPA have health benefits independent of each other, says William S. Harris, Ph.D., professor of medicine at the University of Missouri in Kansas City. EPA, which has been marketed as promoting heart health, is more likely to be beneficial for that purpose than DHA. On the other hand, DHA, which has been touted as a brain food by marketers, may be more likely to promote the proper functioning of brain and nerve tissues than EPA. Dr. Harris recommends striving to get 500 to 1,000 milligrams daily of omega-3 fatty acids, including both EPA and DHA. |
When it comes to reducing risk of colon cancer, there’s evidence that far lower doses of fish oil might help with prevention. In one study, researchers selected people with a history of precancerous growths to see how they responded to fish-oil supplements. The study showed that doses of as little as 2,500 milligrams of fish oil a day could prevent the abnormal cell proliferation that’s associated with the risk of polyps and of colon cancer.
Researchers are also looking into the links between fish oil and reducing childhood asthma, helping women have healthier pregnancies and healthier babies, improving bone growth, and lengthening remission for patients with Crohn’s disease (a chronic inflammatory gastrointestinal disorder) who are already in prolonged remission.
Fish oil might even have an influence on the nervous system. For years, researchers have linked depression with low intake of fish oils. New research shows that supplementing with omega-3 fatty acids may alleviate symptoms of disorders such as schizophrenia.
Easy Does It
Although eating more omega-3–rich fish is beneficial to our health, many experts advise against taking fish-oil supplements.
"I know of no compelling reason to supplement," says Gary J. Nelson, Ph.D., research chemist for the U.S. Department of Agriculture Western Human Nutrition Research Center in San Francisco. "If you eat a good variety of foods, you should be getting plenty of fatty acids in your diet." The only caveat is to make sure that diet includes more of the omega-3 fatty acids and less of the omega-6 fatty acids, he adds.
If you decide to supplement with fish-oil capsules, it’s important to remember that the amount of fish oil used in research studies is extremely high. Patients who take fish oil at the therapeutic levels used in many studies may require 15 to 30 capsules to derive similar benefits.
You can benefit from smaller doses, however, says William S. Harris, Ph.D., professor of medicine at the University of Missouri in Kansas City. "You probably get good health benefits from taking one or two fish-oil capsules a day if you don’t want to eat fish," he says. "But the evidence that fish-oil supplements do this or that at one to two grams (1,000 to 2,000 milligrams) a day is very tenuous."
While both fish-oil capsules and fish have been shown to improve health, fish produces a greater effect on reducing platelet stickiness. Also, fish-oil capsules are high in fat and put stress on our antioxidant defense mechanisms.
Some experts also worry that fish-oil supplements may be contaminated with the same agricultural and industrial pollutants found in fish. For that reason, Andrew Weil, M.D., clinical professor of internal medicine and director of the program in integrative medicine of the University of Arizona College of Medicine in Tucson and author of Eight Weeks to Optimum Health, says that he cannot recommend fish oil in capsule form.
