MONDAY, Dec. 5 (HealthDay News) -- Eating fish rich in omega-3 fatty acids, such as cod and salmon, may significantly lower a young woman's risk of developing heart disease, Danish researchers report.

The researchers found that women of childbearing age who never ate fish had 50 percent more cardiovascular problems than women who ate fish often, and a 90 percent higher risk than women who ate fish weekly.

"We found that even women who ate fish only a couple of times a month benefited," said lead researcher Marin Strom, a postdoctoral fellow at the Center for Fetal Programming at the Statens Serum Institute in Copenhagen.

"Women who eat fish should find the results encouraging, but it is important to emphasize that to obtain the greatest benefit from fish and fish oils, women should follow the dietary recommendations to eat fish as a main meal at least twice a week," she said.

However, the report, published in the Dec. 5 online edition of Hypertension, doesn't show a cause-and-effect relationship between eating fish and lowering cardiovascular risk, merely an association.

Strom's team collected data on some 49,000 pregnant women between 1996 and 2008. They asked how much and what fish they ate, hoping to determine if eating certain types of fish helps reduce the risk of cardiovascular disease. The women, aged 15 to 49 at the study's start, were also asked about lifestyle and family medical history.

Over eight years of follow-up, 577 cardiovascular events -- including hypertension, stroke and heart disease -- were recorded. Five women died of cardiovascular disease.

Overall, more women who ate little or no fish were hospitalized for cardiovascular disease than those who ate fish, the researchers found.

When the researchers evaluated a subset of woman on three different occasions, the risk for cardiovascular disease was three times higher for women who never ate fish than for women who ate fish that was high in omega-3 at least once a week, they added.

Fish oil has long chain omega-3 polyunsaturated fatty acids, which appear to be the protective factor against heart and vascular disease, Strom explained.

"The best sources to obtain the long chained omega-3 fatty acids are fatty fish, such as salmon, herring, mackerel, trout, and Greenland halibut," Strom said.

The fish the women reported eating most often were cod, plaice, salmon, herring, and mackerel. Women who took fish oil supplements were excluded from the study.

Although fried fish may be less healthy, it probably doesn't eliminate the fatty acids, Strom said.

According to Strom, similar studies in the past focused on men, not women. "To our knowledge this is the first study of this size that focuses exclusively on women of childbearing age," she said.

Both sexes share many of the same risk factors for cardiovascular disease, but certain ones, such as inflammation, triglyceride and cholesterol, might be more important in women, she noted.

"This study substantiates a cardioprotective effect of fish intake and underlines the importance of promoting fish intake by dietary recommendations," Strom said. The positive effect noted with even modest fish consumption is encouraging for people who aren't big fish eaters, she added.

The authors acknowledge some limitations to the study, including that the data were self-reported.

Dr. Gregg Fonarow, a professor of cardiology at the University of California, Los Angeles, said the findings are consistent with other studies in older women and in men.

"This study provides further supporting data that omega-3 fatty acids in the diet or as supplements are cardioprotective," Fonarow said.

More information

For more information on heart disease and diet, visit the American Heart Association.