Sizing up omega-3
By Nanci Hellmich, USA TODAY
What should you eat to get enough omega-3 fatty acids in your diet for a healthy heart?
Try eating salmon, sardines, herring, mackerel, trout or swordfish two or three times a week. If you can't stomach those, eat a tuna sandwich a couple of times a week with mayonnaise made with canola oil or soybean oil.
Once a day, you might cook with one of those oils. Or make your salads with those oils or flaxseed oil. Or for variety, try using walnuts or ground-up flaxseeds as a topping for your cereals, say some of the top nutrition researchers on these fats. Or you could take fish-oil supplements.
Scientists have been singing the praises of omega-3 fatty acids for years now. Research has shown that they reduce sudden death from heart attack probably by preventing fatal rhythm disturbances. Two studies, out in April, revealed that people with no heart trouble can safeguard their hearts and reduce their risk of sudden death by eating oily fish twice a week. Plus, other studies link omega-3 fatty acids to potential benefits for the treatment of everything from depression to arthritis to colon inflammation.
But many questions remain unanswered, and, meanwhile, Americans are floundering about what they should be eating.
There still is no final word on how much omega-3 fatty acids a person should consume, but it is clear that many Americans are not getting enough, says Walter Willett, chairman of the department of nutrition at Harvard School of Public Health. He worked on the latest studies on this fat.
For someone who is basically healthy, just having fish several times a week will give most, if not all, of the benefits, he says. "It doesn't seem we need to be eating large amounts of fish every day," says Willett, author of Eat, Drink, and Be Healthy.
Studies in England, France, Italy and India show the benefits of these essential fats, says Artemis Simopoulos, one of the pioneer researchers in this area and author of The Omega Diet: The Lifesaving Nutritional Program Based on the Diet of the Island of Crete with Jo Robinson.
Not just in fish
Fish may be the richest source of long-chain omega-3 fatty acids, but plant foods such as flaxseeds, flaxseed oil, canola oil, unhydrogenated soybean oil and walnuts contain shorter-chain omega-3 fatty acids called alpha-linolenic acid. Some of those can be converted to the long-chain version, Willett says.
It takes about 10 grams of the shorter-chain version to make one gram of the long-chain version, Simopoulos says. Vegetarians and people who really don't like fish should try to add those plant foods to their diet, she says.
Simopoulos and Willett offer these other suggestions for enriching the diet in omega-3 fatty acids:
* Try to incorporate fatty fish into your diet two or three times a week. Besides the omega-3 fatty acid benefits, there are probably some additional advantages in having fish because it's often replacing red meat, which has other downsides, such as large amounts of saturated fat, Willett says.
* Eat your tuna. Simopoulos says many Americans don't like fish such as herring, sardines and salmon, but they will eat tuna, so she tells people to make their tuna salad with canola-oil mayo. Or use canned salmon, mackerel and herring, and make a salad in a similar way, she says.Willett says the tuna can be packed in spring water, soybean oil, canola oil or olive oil.
* Get at least one good source of alpha-linolenic acid most days, Willett says. Flaxseed and flaxseed oil provide the highest concentrations of short-chain omega-3 fatty acids. "Even a teaspoon of flaxseed oil a day would give you a lot. You could add it to a salad. I add a little flaxseed to my multi-grain cereal. It's better absorbed if you put it into a coffee grinder."
* Use mayonnaise and regular salad dressings that are made with canola or soybean oil, Willett says. "Ironically, many people have eliminated their major source of omega-3 fatty acids by going to fat-free salad dressings," he says. (The regular versions are often higher in calories.)
* Cook with canola or olive oil, Simopoulos says.
* Eat walnuts. "They are a perfect food," she says.
* Try foods such as eggs and bread that have been enriched with omega-3 fatty acids, Simopoulos says.
Omega-3 vs. omega-6
The omega-3 picture is muddled by theories about omega-6 fatty acids found in vegetable oils such as corn, safflower, cottonseed and sunflower oils. Simopoulos says people in the USA consume too many of these oils and need to eat a more balanced ratio of omega-6 to omega-3 fatty acids. She doesn't support eating soybean oil, she says, because it's too high in omega-6.
Willett says there is no evidence that the levels of omega-6 fatty acids consumed in the USA are harmful, and in fact, there is evidence of benefit.
He says people who have had a heart attack who are not going to eat fish regularly might want to take a supplement that contains one gram of omega-3 fatty acid. He says there may be some additional benefits from higher doses for the heart (keeping blood platelets from clumping together), but those benefits are small and more easily obtained by taking a baby aspirin daily or every other day.
Others believe people should consume higher doses of omega-3 fatty acids. Best-selling diet author Barry Sears, whose The Omega Rx Zone is out this month, doesn't think that fish twice a week provides enough omega-3 fatty acids necessary for all the potential health benefits. He recommends supplements that provide at least 2.5 grams per day. (He sells his brand of supplements.)
For those who do eat fish, shop carefully.
Farm-raised fish are less likely to be contaminated by mercury and other poisons than ocean-caught fish, but they may not be as high in omega-3 fatty acids, depending on what they were fed, Willett says. If the fish are fed other fish or algae, they will have a high content of omega-3 fatty acids, he says. But if they are fed wheat and corn, they won't contain as much.
"We need to be monitoring this," he says. "And it may well be that there needs to be a label that gives the omega-3 fatty acid content of farmed fish."
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