Heart Healthy Fish? Not if You Don't Cook it RIght

Eating fish for your heart? How you cook it is very important.

If you eat fish to gain the heart-health benefits of its omega-3 fatty acids, how you prepare it matters a lot.

“It appears that boiling or baking fish with low-sodium soy sauce (shoyu) and tofu is beneficial, while eating fried, salted or dried fish is not,” said Lixin Meng, M.S., lead researcher of the study and Ph.D. candidate at the University of Hawaii at Manoa. In fact, she added, eating fried, salted or dried fish may contribute to your risk. We did not directly compare boiled or baked fish vs. fried fish, but one can tell from the (risk) ratios, boiled or baked fish is in the protective direction but not fried fish.”

The findings also suggest that the cardioprotective benefits of fish vary by gender and ethnicity — perhaps because of the preparation methods, genetic susceptibility or hormonal factors.

In this study, researchers examined the source, type, amount and frequency of dietary omega-3 ingestion among gender and ethnic groups. Participants were part of the Multiethnic Cohort living in Hawaii and Los Angeles County when they were recruited between 1993 and 1996. The group consisted of 82,243 men and 103,884 women of African-American, Caucasian, Japanese, Native Hawaiian and Latino descent ages 45 to 75 years old with no history of heart disease.

Overall, men who ate about 3.3 grams per day of omega-3 fatty acids had a 23% lower risk of cardiac death compared to those who ate 0.8 grams daily. “Clearly, we are seeing that the higher the dietary omega-3 intake, the lower the risk of dying from heart disease among men,” Meng said. Interestingly, for women, the omega-3 effect was cardioprotective at each level of consumption.

However, eating salted and dried fish was a risk factor in women. In contrast, adding less than 1.1 gram/day shoyu and teriyaki sauce at the dinner table was protective for men. But more was not better: adding more than 1.1 gram/day of such sauce was not beneficial. For women, shoyu use showed a clear inverse relationship to death from heart disease. Shoyu high in sodium can raise blood pressure, so she stressed low-sodium products. Eating tofu also had a cardioprotective effect in all ethnic groups.

“My guess is that, for women, eating omega-3s from shoyu and tofu that contain other active ingredients such as phytoestrogens, might have a stronger cardioprotective effect than eating just omega-3s,” said Meng, noting that further studies are needed to confirm the hypothesis.

Comment: There is good reason to tell your doctor about all supplements you take. For example, excessive intake of omega-3 fats tends to prevent blood from clotting and may cause excessive nose bleeding.