Nov. 19, 2009 (Orlando, Fla.) -- When it comes to reaping the heart-healthy benefits of omega-3 fatty acids in fish, it often comes down to how you prepare it, a study shows.
"The take-home message is that it's better to bake or boil the fish instead of frying it," says study researcher Lixin Meng, MS, a doctoral candidate at the University of Hawaii at Manoa. And adding a dash of low-sodium soy sauce will enhance the heart-healthy benefits, she tells WebMD.
Eating salted, dried, or fried fish, on the other hand, is not beneficial, Meng says. "But if it’s a fun occasion and you really want fried fish, do it the Japanese way -- stir-fry, rather than deep-fry it."
If the idea of eating fish, no matter how it's prepared, turns you off, take heart: Other researchers report they've genetically engineered soybean plants to produce oil that boosts levels of certain omega-3 fatty acids in the blood.
"This soybean oil could be an effective alternative to fish oil as a source of heart-healthy omega-3 fatty acids," says researcher William Harris, PhD, chief of cardiovascular health research at the University of South Dakota's Sanford School of Medicine in Sioux Falls.
Both new studies were presented at the American Heart Association's (AHA) Scientific Sessions 2009.
Omega-3s Cut Heart Risk
The AHA recommends eating at least two servings of fatty fish rich in omega-3 fatty acids like DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) a week to protect against heart disease, says AHA spokeswoman Alice Lichtenstein, DSc, a nutritionist at Tufts University.
Salmon, sardines, tuna, halibut, and mackerel are among the fish that are richest in omega-3s.
"How you cook the fish, the type of fish, and the amount of fish you consume [all impact its health-health benefits], but not enough attention has been placed on the best way to ensure you get enough of the fatty acids in your diet," says Lichtenstein, who was not involved with the work.
To help fill in the knowledge gap, Meng and colleagues examined the source, type, amount, and frequency of dietary omega-3 consumption among men and women in different ethnic groups.
The study involved 82,243 men and 103,884 women, ages 45 to 75, in Los Angeles and Hawaii. The participants represented five major ethnic groups: African Americans, whites, Hispanics, Japanese-Americans, and native Hawaiians. None suffered from heart disease at the start of the study.
Over the next 10 years, 2,604 of the men and 1,912 of the women died from heart disease.
When the men on the study were divided into five groups depending on their omega-3 intake, those in the highest group consumed an average of about 3.3 grams of omega-3 fatty acids daily. Men in the lowest group consumed about 0.8 grams a day.
Men in the highest group of omega-3 intake had a 23% lower risk of dying due to heart disease than those in the lowest group, the study showed.
Men of white, Japanese, and Hispanic descent appeared to get more benefits from omega-3s than African-American or Hawaiian men, possibly because of how they cook the fish or genetic predisposition, Meng says.
In women, the link between omega-3 fatty acid intake and heart disease wasn't as strong, she says.
Baked Fish vs. Fried Fish
The researchers did not directly compare boiled or baked fish to fried fish. But when the men were divided into three groups depending on how often they baked or boiled their fish, those in the top third were 10% less likely to die from heart disease than those in the lowest third.
Also, men and women who ate the most fried fish were 12% more likely to die from heart disease than those who ate the least fried fish.
Both men and women who ate the most salted or dried fish were 15% more likely to die from heart disease than those who ate the least.
The study also showed that low-sodium soy sauce and tofu protected women against death from heart disease. "Omega-3 fatty acids from plant sources may do more to improve women's heart health than those from fish sources," Meng says.
Genetically Engineered Soybeans
The second study was designed to find a way to get more omega-3 fatty acids into people's diets without making them eat more fish, Harris says.
"The Japanese eat twice as much fish as Americans and have much less heart disease. We can tell people to eat more fish, but that doesn't mean they will," he tells WebMD.
So just as "we fortify salt with iodine and put folic acid into processed grain products, we decided to put fatty acids into oil," Harris says.
The study, which involved 157 healthy volunteers, showed that the genetically engineered soybean oil and pure EPA capsules boosted EPA levels in the body to a similar degree. In contrast, regular soybean oil didn’t raise EPA levels at all.
More tests are needed to ensure the high-tech oil has the same effect once put into foods, Harris says.
The next step, he says, is to incorporate the genetically engineered -- and tasteless -- soybean oil into products such as breakfast bars, yogurts, margarine, and salad dressings.
The engineered soybeans also need to be approved by regulators at the Department of Agriculture before planting can begin, according to a spokesperson for Monsanto Co., which developed the biotech oil and funded the new research.