The study – published in Hypertension: Journal of the American Heart Association – is the first population based study to assess the risk of developing cardiovascular disease (CVD) in women of childbearing age.
The researchers found that women who rarely or never ate fish had 50% more cardiovascular problems over eight years than those who ate fish regularly. Compared to women who ate fish high in omega-3 weekly, the risk of CVD was 90% higher for those who rarely or never ate fish, said the Danish research team.
"To our knowledge this is the first study of this size to focus exclusively on women of childbearing age," said Dr Marin Strøm of the Statens Serum Institut, Denmark – who led the study.
Strøm noted that in general, the big challenge with putting across health messages to younger generations is that the benefits may not be evident for 30 or 40 years. However, she noted that when it comes to omega-3 and heart benefits, the new study shows “this is not the case.”
“We saw a strong association with cardiovascular disease in the women who were still in their late 30's," she explained.
"Our study shows that for younger women, eating fish is very important for overall health, and even though we found cardio-protective effects at relatively modest dietary levels, higher levels may yield additional benefits," said Strøm.
The study adds to an ever-growing body of science supporting the potential cardiovascular health benefits of omega-3 fatty acids.
The heart health benefits of fish oil, and the omega-3 fatty acids it contains, are well-documented, being first reported in the early 1970s by Dr Jorn Dyerberg and his co-workers in The Lancet and The American Journal of Clinical Nutrition.
To date, the polyunsaturated fatty acids (PUFAs) have been linked to improvements in blood lipid levels, a reduced tendency of thrombosis, blood pressure and heart rate improvements, and improved vascular function.
The new study, which compared hospital admissions for heart related health problems with fish and omega-3 intake, adds to this by providing evidence for the benefits of omega-3 in young women – an area that until now has received little focus, with many previous studies examining links in men and older people.
"Men and women share many cardiovascular risk factors, but some studies have shown that there might also be gender differences,” said Strøm.
“For example, inflammation, cholesterol, and triglyceride levels may have a more negative influence among women," she explained
Strøm and her team analysed the data from nearly 49,000 pregnant women aged between 15 and 49. The nationwide cohort of Danish women were asked about dietary behaviours and then followed up by checking hospital records for CVD related admissions.
The researchers said that because very few women were found to take fish oil supplements, those that did were excluded from the analyses, so that the results could be based purely on dietary intake of omega-3 fatty acids.
The team reported that both inpatient and outpatient admission for cardiovascular disease was much more common among women who reported eating little or no fish.
In three different assessments over a 30-week period, women who never ate fish had a three-fold higher disease risk compared to women who ate fish every week, they said.
Strøm and her team said that the results showed that even in women who ate fish only a few of times a month benefitted.
"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.
Published online ahead of print, doi: 10.1161/HYPERTENSIONAHA.111.179382
“Fish, n-3 Fatty Acids, and Cardiovascular Diseases in Women of Reproductive Age: A Prospective Study in a Large National Cohort”
Authors: M. Strøm, T.I. Halldorsson, E.L. Mortensen, C. Torp-Pedersen, S.F. Olsen