For maximum healthy benefits from eating fish, Hawaii researchers advise baking or boiling it and adding low-sodium soy sauce or tofu.

“;I think the shoyu was a little bit of a surprise,”; said Lixin Meng, University of Hawaii at Manoa doctoral researcher in epidemiology and lead researcher. “;But when I'm thinking about it, I feel it makes sense.”;

“;After I did the research, I tend to eat more tofu and shoyu and to season with shoyu. I believe it's healthy for me.”;

Many studies suggest that eating omega-3 fatty acids reduces the risk of heart disease, but not much is known about the most beneficial source.

So Meng studied the source, type, amount and frequency of dietary omega-3 ingestion among men and women in different ethnic groups. Co-authors are Dr. Lynne Wilkens and Dr. Laurence Kolonel at the Cancer Research Center of Hawaii.

Participants were members of a Multiethnic Cohort recruited for population studies between 1993 and 1996 in Hawaii and Los Angeles County. The group included 82,243 men and 103,884 women of African, Caucasian, Japanese, native Hawaiian and Latino descent. They were 45 to 75 years old with no history of heart disease.

Meng presented her findings yesterday at the American Heart Association's Scientific Sessions 2009 in Orlando, Fla., and discussed them in an interview.

She said it is not beneficial to eat fried, salted or dried fish.

The researchers did not directly compare boiled or baked fish versus fried fish, but she said, “;One can tell from the (risk) ratios, boiled or baked fish is in the protective direction, but not fried fish.

“;Living in Hawaii, there is more chance to eat fish,”; Meng said, suggesting ocean fish such as tuna or mackerel have a lot of omega-3 fatty acids. “;A lot of people are eating snapper and salmon.”;

The researchers examined preparation methods (except for grilled fish) and divided into subgroups participants' intake of canned tuna, other canned fish, fish excluding shellfish and soy products (soy, tofu and shoyu) that contain plant omega.

Those in the highest subgroup consumed a median 3.3 grams of omega-3 fatty acids daily. The lowest consumed a median of 0.8 grams a day.

Men who ate about 3.3 grams per day of omega-3 fatty acids overall had a 23 percent lower risk of cardiac death than those eating 0.8 grams daily, the study found. “;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.

Men of Caucasian, Japanese and Latino descent appear more likely to get health benefits from fish than African-American or Hawaiian men, possibly because of how fish is prepared or genetic predisposition, according to the findings.

Women gained some heart protection whenever they consumed fish, but it was not consistently significant, and salted and dried fish was a risk factor for them, Meng said.

Other findings:

» Adding less than 1.1 gram per day of shoyu and teriyaki sauce was protective for men. Shoyu high in sodium can raise blood pressure, Meng pointed out.

» Eating tofu had a cardio-protective 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 strong cardio-protective effect than eating just omega-3,”; Meng said.

During an average follow-up of 11.9 years, the study group had 4,516 heart-related deaths, according to state and national death records which were cross-referenced through the end of 2005.

Dietary changes over time and effects of fish oil supplements were not considered in the study, funded under an American Heart Association Pacific Mountain Pre-doctoral Fellowship grant.