HELSINK -- A recent study conducted by the University of Eastern Finland showed that increased intake of fatty fish can boost the level of high density lipoprotein (HDL), know as the good cholesterol.

Fish consumption has long been believed to be good for health and people with higher levels of HDL tend to have lower risks of cardiovascular diseases. However, how fats and other useful nutrients in fish function in human body are not fully known.

The new study, according to a press release by the university, found that a higher intake of fish increases the number of large HDL particles, which function in sweeping extra cholesterol off artery walls and therefore reduce risks of cardiovascular diseases.

A total of 131 middle-aged persons who were at risk of developing cardiovascular disease, participated in the study. They were found to have the so-called metabolic syndrome characters, such as impaired glucose tolerance, obesity, hypertension or elevated blood fat levels.

The participants were asked to record what they had eaten, and their blood samples were checked before and after the three-month study.

As a result, increased number of large HDL particles were observed in persons who ate at least 3 to 4 fish meals a week. What the participants ate were fatty fish, such as salmon, rainbow trout, herring and vendace. No butter or cream was added in the cooking.

"People shouldn't fool themselves into thinking that if their lipid levels are OK, there's no need to think about the diet, as things are a lot more complicated than that. Soft vegetable fats and fish are something preferred in any case," said Maria Lankinen, postdoctoral researcher from the university.

Researchers also laid emphasis on a dietary approach to lower levels of total cholesterol and low density lipoprotein, known as bad cholesterol.

The research findings were published in the latest issue of PLOS ONE.