DIETARY-PROTEIN AND BLOOD-PRESSURE

Objective.-To review published and presented data on the relationship between dietary protein and blood pressure in humans and animals. Data Sources.-Bibliographies from review articles and books on diet and bl ood pressure that had references to dietary protein. The bibliographie s were supplemented with computerized MEDLINE search restricted to Eng lish language and abstracts presented at epidemiologic meetings. Study Selection.-Observational and intervention studies in humans and exper imental studies in animals. Data Extraction.-In human studies, systoli c or diastolic blood pressure were outcome measures, and dietary prote in was measured by dietary assessment methods or by urine collections. In animal studies, blood pressure and related physiological effects w ere outcome measures, and experimental treatment included protein or a mino acids. Data Synthesis.-Historically, dietary protein has been tho ught to raise blood pressure; however, studies conducted in japan rais ed the possibility of an inverse relationship. Data analyses from subs equent observational studies in the United States and elsewhere have p rovided evidence of an inverse relationship between protein and blood pressure. However, intervention studies have mostly found no significa nt effects of protein on blood pressure. Few animal studies have speci fically examined the effects of increased dietary protein on blood pre ssure. Conclusions.-Because of insufficient data and limitations in pr evious investigations, better controlled and adequately powered human studies are needed to assess the effect of dietary protein on blood pr essure. In addition, more research using animal models, in which exper imental conditions are highly controlled and detailed mechanistic stud ies can be performed, is needed to help provide experimental support f or or against the protein-blood pressure hypothesis.