Fish Oil : HYPE OR HOPE? : Scientists Say Omega-3 Keeps Cholesterol From Building Up in Arteries
Much attention has been focused recently on the growing popularity of vitamin/mineral-fortified products and vitamin/mineral supplements as a means of promoting health. It seems many people want a “quick fix”--opting to improve their health with these products instead of building a healthy body from a wide variety of food sources.
The latest development for the pill-popping generation is fish oil supplements. The supplements are being lauded because one of their components--omega-3 fatty acid--is implicated in everything from the reduction of serum cholesterol levels in the bloodstream to its ability to relieve the discomforts of immune system diseases, skin disorders and allergies.
But is all this hype about omega-3 just another food fad? The jury is still out on supplementation, but the results of epidemiologic studies on people who eat fish instead of red meat are encouraging.
Physicians and nutritionists gathered in Los Angeles recently for a symposium discussing the possible role of fish oils in the American diet. The discussions included a historical perspective on coronary heart disease in the United States, revealed the results of research data on the effects of fish oils in the body and suggested ways of designing diets to include fish rich in omega-3.
The panel included Dr. William P. Castelli, director of the Framingham Heart Study and lecturer at Harvard University Medical School; Dr. Alexander Leaf, chairman of the department of preventive medicine and clinical epidemiology at Harvard University Medical School; Dr. Artemis P. Simopoulos, director of the Nutritional Sciences International Life Sciences Institute Research Foundation, and Carolyn Crimmins, clinical nutritionist at Massachusetts General Hospital/Harvard Cardiovascular Health Center.
The idea of substituting fish in the diet for more saturated sources of protein like red meat is not new. Neither is supplementation. The American Heart Assn. has stated that it’s possible to lower the amount of red meat in the diet by eating more fish and poultry, and mothers have included a dose of cod liver oil in their children’s diets for generations. Today’s renewed interest in fish oil supplementation comes on the heels of research seeking an explanation for the prevalence of coronary heart disease in Americans. The results were surprising.
Epidemiologic studies of Greenland Eskimos and Japanese and Dutch fishermen confirmed that deaths from cardiovascular disease occurred at a lower rate compared to the death rate for Americans. Yet the Eskimo diet tends to be extremely high in cholesterol; it is largely made up of whale blubber and seal meat, in which fat is excessive. The American diet is also high in fat but the Eskimos also eat large amounts of cold-water fish such as salmon, sardines, mackerel and herring.
The scientists surmised there was something in the blood of fish inhabiting the icy waters of the north that counteracts the Eskimos’ high-fat diet. The conclusion was that it was omega-3 fatty acid.
Omega-3 is a polyunsaturated fat that helps to keep the systems of cold-water fish fluid. The Eskimos and Japanese fisherman who ingest fish with high amounts of this substance in their meat tend to benefit from its anti-inflammatory and fluid-inducing effects. “Fish oils counteract the constricting quality of other acids and fats on blood vessels,” Leaf said.
The scientists concluded that because of its fluidity, omega-3 is responsible for keeping cholesterol from building up in the arteries of those who eat it, thus reducing the occurrence of diseases like arteriosclerosis, coronary heart disease and high blood pressure, even in high-fat diets.
The clinical definition of omega-3 fatty acid is a technical one that includes terms like eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), triglycerides, lipoproteins and lipids. It is more important to remember that omega-3 fatty acid in fish oil seems to act in three ways to benefit the body: It lowers blood fat levels by sweeping away harmful levels of “bad” fats, which are the major cause of coronary heart disease; it keeps blood flowing by forming platelets (cells that clot) that are less sticky and therefore less likely to clot and jam arteries--a chief cause of strokes; and it lowers total cholesterol levels, which are linked to heart disease.
“Omega-3 fatty acids affect membrane fluidity and permeability by altering the activity of membrane-bound enzymes or by other mechanisms not yet understood,” Simopoulos said. “Today we have evidence that omega-3 fatty acids (1) have beneficial effects on the cardiovascular system via their hypolipidemic, antithromboic and blood-pressure-lowering effects, (2) have anti-inflammatory, immunologic and possibly anti-cancer effects (their role in allergic conditions, colitis, asthma, lupus erythematosus and arthritis are being investigated), and (3) may be essential for normal growth and development of human beings since they are found in large amounts in the retina, brain and testes.”
Optimum Benefits
Physicians are now recommending at least three to four fish meals per week for optimum benefit. There has been no recommended intake for fish oil capsules.
“There are several ways to enrich the daily diet with omega-3 to reap the benefits of heart-healthy eating,” Crimmins said. “. . . Americans want to focus on ‘just tell me what foods I can eat’ but we need to reinforce dietary goals.”
She suggests a “prudent diet” that is low cholesterol, low total and saturated fat and high fiber. “All fish contain omega-3 fatty acids, though fattier fish contain more omega-3 than leaner species of the fish,” she said.
There have been some studies showing adverse effects of consuming fish oil capsules--in some cases supplements have actually worsened conditions in people who already have a blood lipid disorder. So the bottom line is that it is unwise to self-medicate.
A good source of basic information is a new book entitled, “The Omega-3 Breakthrough” by Julius Fast (Body Press, a division of HP Books: $15.95).
Fast, himself a victim of coronary occlusion, who underwent coronary angioplasty--a surgical procedure that reduces the risk of a heart attack--doesn’t encourage the use of pills. His book focuses on doctor recommendations for three fish meals per week and contains meal plans and recipes.
No on Supplementation
For those seeking approval for supplementation, this book doesn’t give it. Fast includes as a deterrent to this practice a chart showing the varying amounts of omega-3 found in different brands of fish oil capsules and discusses the possibility of Vitamin A poisoning, since fish oil is a rich source of the vitamin.
The book offers a maintenance diet for those who want to increase omega-3 in their diets without affecting calorie intake. It also offers two low-calorie diets--one designed for men, one for women--as well as chapters on buying, cooking and serving fish.
Fast explains in layman’s terms how fish oil affected the Eskimo diet in the epidemiologic studies. In technical but understandable detail, he describes how omega-3 works in the body and gives details on some of the clinical studies--how they relate to pharmacologic uses of fish oil supplements in treating diabetes, skin disorders, allergies, arthritis and asthma.
Here are a few recipes using sardines, an excellent source of omega-3. According to the Norway Sardine Industry, sardines in oil have about 5.5 grams of omega-3 per 3 3/4-ounce can, drained. The same size serving in either soy or olive oil contain 3.1 grams. Low-sodium sardines in water contain 4.5 grams. Sardines are also a superior source of calcium--a three-ounce serving contains about 372 milligrams.
SARDINE SUSHI
1 1/2 cups short grain rice
2 teaspoons sugar
2 tablespoons vinegar
4 (8x6-inch) sheets nori (dried seaweed)
2 (3 3/4-ounce) cans sardines in oil, drained
Carrots, green onions, cucumber or radishes, cut julienne
Rinse rice until water runs clear, then drain. Combine rice and 1 1/2 cups water in 3-quart saucepan. Cover and bring to boil, then reduce heat and cook, without stirring, until water is absorbed, about 15 minutes.
Dissolve sugar in vinegar, then stir into rice. Spread rice on baking sheet and fan with piece of cardboard to cool quickly. Let stand at room temperature to cool completely.
To assemble, place 1 sheet nori, shiny side down, on bamboo sushi mat so you can roll up from long end. Spread about 1/4 of rice evenly over nori, leaving 1-inch margin at top to seal roll. Arrange layers of sardines and vegetables across center of rice parallel to margin.
Starting from long end, roll up mat to enclose filling. Press mat gently around roll to shape, then moisten margin of nori with water and seal roll snugly. Remove mat and press in lose ends. Place, seam side down, on cutting board. Repeat with remaining nori and filling. Slice into 1-inch rounds with sharp, wet knife. Makes 16 (2-piece) servings.
SESAME-SARDINE SUSHI
2 (3 3/4-ounce) cans sardines in oil, drained
1/4 cup finely chopped green onions
1 tablespoon soy sauce
1 tablespoon sesame seeds
1 teaspoon plus 3 tablespoons vinegar
1 teaspoon lemon juice
1 1/2 cups short grain rice
2 teaspoons sugar
4 (8x6-inch) sheets nori (dried seaweed)
Combine sardines, green onions, soy sauce, sesame seeds, 1 teaspoon vinegar and lemon juice in bowl. Set aside.
Rinse rice in water until water runs clear, drain. Combine rice and 1 1/2 cups water in 3-quart saucepan. Cover and bring to boil, then reduce heat and simmer until water is absorbed, about 15 minutes.
Combine sugar and remaining 3 tablespoons vinegar and stir into hot rice. Spread rice on baking sheet and fan with piece of cardboard to cool quickly. Let stand at room temperature until completely cooled.
Place 1 piece nori, shiny side down, on bamboo sushi mat so that you can roll up from long end. Spread about 1/4 of rice evenly over nori, leaving 1-inch margin at top to seal roll. Spread sardine mixture over center of rice parallel to margin.
Starting from long end, roll mat to enclose filling. Press mat gently around roll to shape, then moisten margin of nori with water and seal roll snugly. Remove mat, press in loose ends and place, seam side down, on cutting board. Repeat with remaining nori and filling. Slice into 1-inch rounds with sharp, wet knife. Makes 16 (2-piece) servings.
SARDINE SUMMER SALAD
Butter lettuce
3 cups cooked rice, chilled
1 medium cucumber, sliced
2 large carrots, shredded
1 bunch radishes, trimmed and halved
12 medium mushrooms, halved
2 (3 3/4-ounce) cans sardines in oil, drained
1/4 cup sliced green onions
Sesame Dressing
Line serving platter with lettuce. Mound rice in center. Arrange cucumber, carrots, radishes, mushrooms and sardines on lettuce, surrounding rice. Sprinkle with green onions and serve with Sesame Dressing. Makes 4 servings.
Sesame Dressing
1/2 cup vinegar
6 tablespoons oil
2 tablespoons sugar
1 1/2 tablespoons soy sauce
1 1/2 teaspoons dry mustard
3 tablespoons toasted sesame seeds
Combine vinegar, oil, sugar, soy sauce, mustard and sesame seeds in blender container and blend 1 minute. Store refrigerated in covered container up to 1 week. Mix before serving.
