1. The diet containing white fish meal or casein as protein source could markedly depress the elevation of blood pressure, prevent the incidence of stroke and elongate the life span in SHRSP. The incidence of stroke in SHRSP was prevented by providing these diets from an early age, the earlier the better. A high content of protein was more effective than a low content, but it seems that there may be an ideal protein content level somewhere.
2. White fish meal, casein, euphausia, beef, and soy bean cake used as protein sources were digested with pepsin in the stomach, and trypsin in the duodenum, and hydrolyzed to amino acids and peptides. It seemed that there were antihypertensive substances in these peptides. These peptides were absorbed and played a role in the slowing of the elevation of blood pressure and the prevention of stroke.