By: Kristin Lund
It’s been known for some time that omega-3 fatty acids decrease the risk of heart disease, but no one has really known if one dietary source is better than another. For that reason, Lixin Meng, MS, a PhD candidate at the University of Hawaii at Manoa, designed a study to compare sources, types, amounts, and frequencies of omega-3 in diets, while taking into account gender and ethnic groups. The study was presented at the American Heart Association’s 2009 Scientific Sessions.
The American Heart Association website recommends “eating fish (particularly fatty fish) at least two times a week. Fish is a good source of protein and doesn’t have the high saturated fat that fatty meat products do. Fatty fish like mackerel, lake trout, herring, sardines, albacore tuna, and salmon are high in two kinds of omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).”
One of the most surprising findings by the University of Hawaii researchers was that cooking fish rich in omega-3 fatty acids with low-sodium soy sauce or tofu increases the benefits. It’s not so surprising that eating fried, salted, or dried fish is not as beneficial. In fact, the researchers went so far as to say that preparing the fish by some methods may actually be detrimental to your health. Baked or boiled fish was found to be the most heart-healthy.
The study also revealed that the heart healthy benefits of eating foods rich in omega-3 fatty acids differ by gender and ethnicity. It is unclear if this is because of different methods of preparation, genetic differences, or hormonal factors.
The researchers found that omega-3 intake decreased the overall risk of death from heart disease in men. The study showed that men who consumed an average of 3.3 grams per day of omega-3 fatty acids had a 23 percent lower risk of death from heart disease than those who ate 0.8 grams daily. The trend was noted in mainly Caucasians, Japanese Americans, and Latinos, however, because the study included very few blacks or Hawaiians, so Meng cautioned that this result must be interpreted with care.
The researchers found that women who consumed omega-3 were healthier, but there was not a consistent difference between women who consumed a small amount and women who consumed a large amount. The researchers said, however, that salted and dried fish were definitely a risk factor in women. Using no more than 1.1 gram/day of shoyu (soy sauce) and teriyaki sauce was found to be acceptable for men, but women who used shoyu were more likely to die from heart disease. It could be because shoyu is high in sodium, which can elevate blood pressure, so the researchers emphasized that low-sodium soy sauce should be used.
Tofu (bean curd) was good for the heart in all ethnic groups. The researchers hypothesize d that women who get their omega-3s from shoyu and tofu that has other active ingredients, such as phytoestrogens, might be enjoying a more powerful heart-healthy effect than that from eating just omega-3s. But more research is needed to find out if this is true.
The researchers plan to continue their work, due to limitations of the first part of their study. They did not take into account possible dietary changes over time or whether participants might have changed their eating patterns after entering the study. They also did not factor in whether people were supplementing their diets with fish oil.
Lead researcher Meng said that continued research could help people understand how much fish they need to eat to protect their heart health and how to prepare it for maximum health benefits.
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Source: American Heart Association