Eating fish twice a week may be better than taking supplements for preventing heart disease, according to the new health guidelines by the European Society of Cardiology.

While it is generally assumed that cardiovascular health benefits of fish are from fish oils, like omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), scientific research has not confirmed this. 

The new guidelines indicates that one of the two weekly portions of fish should be oily fish, like salmon, mackerel, sardine or trout, because these fish contain the highest concentrations of omega 3 fatty acids. 

Researchers recommend that people who don’t like fish take pharmaceutical grade products instead of over-the counter supplements because not all over the counter capsules contain the same dose of fatty acids, and many do not contain sufficient amounts of omega 3.

"Omega-3 fatty acids are really important to human health, whether you're talking about CVD, brain or immune health. Heath professionals have a key role to play in educating the public about the beneficial effects of including fish in their diets," Philip Calder, a metabolic biochemist and nutritionist from the University of Southampton, said in a statement.

"It's important that health professionals give clear guidance around the need for patients to take 1g of omega-3 a day to achieve any beneficial effects. With over the counter brands containing different concentrations there's a danger people may not be receiving sufficient intakes," Calder said.

However, experts still conclude that eating fish is still better than taking supplements.

"This is because fish contain all sorts of other nutrients like vitamin D, selenium and iodine that may also be beneficial against CVD. And we don't have the final proof that the benefits from eating fish come from the omega-3," Daan Kromhout of Wageningen University, in the Netherlands said in a news release.

"Fish, it needs to be remembered, don't provide a total panacea against cardiovascular disease. As well as consuming fish, people need to eat healthy diets, not smoke and be physically active," he added.