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.