Dietary intake of total, animal and plant proteins and the risk of coronary heart disease and hypertension: a systematic review and dose-response meta-analysis of prospective cohort studies

Background & Objectives Previous findings assessing the association between long-term protein intake and cardiovascular diseases (CVDs) are inconsistent. This study aimed to summarize previous investigations on the association between total, animal and plant proteins intake and the risk of coronary heart disease (CHD) and hypertension (HTN) in adults. Methods Related papers were found by searching through PubMed/Medline, Scopus, and Google Scholar up to April 2020. Prospective cohort studies examined the association between consumption of the dietary protein from different sources and the risk of CHD and HTN in general population, were included. The random-effects model was used to pool the reported relative risks (RR). Dose-response associations were modeled by restricted cubic splines. Results Thirteen prospective studies, in total, including 547,303 participants- 11,590 cases with total CHD and 5,620 with HTN- were included. Dietary intake of total protein was not significantly associated with the risk of total CHD (RR: 0.97; 95%CI: 0.90-1.05) and HTN (RR: 1.01; 95% CI: 0.90-1.14). Moreover, consumption of both dietary plant and animal protein was not related to the risk of total CHD and HTN. Dose-response analysis indicated that the risk of CHD and HTN did not change significantly with increasing dietary total protein intake from 10% to 25% of total calorie intake. Conclusions Dietary protein intake from different sources had no significant association with risk of CHD and HTN. Further high-quality research is needed to examine the potential mechanistic links between dietary protein intake and health outcomes.