Eating oily fish may boost women’s heart health more than men’s, claim researchers.
The oils – found in fish like salmon, mackerel and tuna – are known to improve chances of surviving a repeat heart attack.
But a new study suggests women could benefit more from their effect on the heart.
Researchers at the University of Reading found fish oils have a direct impact on the muscle cells that control the elasticity of our blood vessels.
In tests, women got double the benefit compared with men as elasticity improved four-fold in women compared with two-fold in men.
In fact the beneficial effect of the fish oil in women was as potent as that of drugs that are prescribed to people with poor blood vessel elasticity, such as those with diabetes.
At least 39,000 women a year in the UK suffer heart attacks and their chances of dying are higher than a man’s.
Study leader Professor Christine Williams, the University’s first Hugh Sinclair Professor of Nutrition and Pro Vice-Chancellor for Research and Innovation, said: ‘Studies examining women’s heart health are much less common than those which study men, partly because the studies are harder to carry out in women due to the varying effects of hormones during the menstrual cycle.
‘In addition, many believe men are the only ones to suffer from heart disease.
‘However nearly 40,000 women die of coronary heart disease each year in the UK and we do not yet know whether all the diet recommendations which we currently advise are as effective for women as for men.
‘The good news here is that current recommendations that we should all eat more oily fish appears to be more effective for women than men.’
However, two thirds of Britons never eat oily fish even though official guidelines recommend its consumption at least once a week.
In the study around 60 people, half men and women, were given test drinks containing either saturated fats or a combination with omega 3 fish oils, equivalent to a 200g portion of oily fish.
Imaging was used to check the reaction of the blood cells to the different drinks, says a report in the Journal of Lipid Research.
Prof Williams said ‘As well as discovering the effect of fish oils is greater in women we also found that people with a gene variation that produces the protein eNOS, which helps to increase blood flow, also benefitted more.
‘Our study showed that people who carry the rarer form of the protein, which is about 10 per cent of the UK population, respond twice as well to fish oils, suggesting they would particularly benefit from additional oily fish intake.
‘This research supports the view that the effects of diets vary, being more effective in certain genders and genotypes. Our study was very carefully designed to include equal numbers of men and women and also equal numbers of people with the two types of gene variants, so that the results are very unlikely to be due to chance. ‘Although the responses varied, all the subjects in the study benefitted from taking fish oils with a meal.
‘However, for women and those with the gene variant, the responses were very marked indeed, and when it comes to their diet could give them considerable health benefits in the future.’ The work was funded by the Biotechnology and Biological Sciences Research Council.
Fish oil is known to increase the release of nitric oxide from the lining of the blood vessel wall which causes relaxation of the vessel and increases blood flow.
However the researchers found that some of the relaxation effect on the blood vessel wall may be due to direct actions of the fish oil acting on the muscle cells themselves, rather than on the cells lining the blood vessel wall.
Professor Williams added ‘This is an exciting discovery which gives us a new way of looking at how our diet affects the health of our blood vessels, and possibly more effective ways of improving heart health in the future.’ The best dietary source of omega 3 fatty acids is oily fish because the human body cannot produce omega-3 fatty acids.
There has been an explosion in the number of foods fortified with omega-3 oils, such as chickens, margarine, eggs, milk and bread, but they contain only small amounts.
Types of fish that contain high levels include tuna, salmon, mackerel, herring, sardines, and anchovies.
White fish is also a healthy food including cod, haddock and plaice although it contains lower levels of essential fatty acids.
Fish oil supplements are recommended as protection against repeat heart attacks, with regular fish eaters a third more likely to survive a heart attack.