Specialists from Harvard University have proved that consumption of at least 85g of salmon or 170g. of mackerel per one week reduces risk of death caused by heart diseases by 36% and can extend human’s life span by 17%. The healthiest fish are fat, containing plenty of Omega 3 acids. The iron is a necessary ingredient of human red cells. The hemoglobin which is co-built by the iron is responsible for proper circulation of blood in a human body.