To perform a meta-analysis of prospective studies to evaluate the relation between dietary protein intake and stroke risk.
Relevant studies were identified by searching PubMed and Embase through November 2013, and by reviewing the reference lists of retrieved articles. We included prospective cohort studies that reported relative risks (RRs) with 95% confidence intervals (CIs) for the association between dietary protein intake and stroke risk.
The meta-analysis included 7 prospective studies involving 254,489 participants. The pooled RR of stroke for the highest compared with the lowest dietary protein intake was 0.80 (95% CI 0.66-0.99). Dose-response analysis indicated that a 20-g/d increment in dietary protein intake was associated with a 26% reduction in stroke risk. Stratifying by protein type, the RR of stroke for animal protein was 0.71 (95% CI 0.50-0.99). Sensitivity analysis restricted to studies with control for common risk factors yielded similar results, and omission of any single study did not change the overall result.
These findings suggest that moderate dietary protein intake may lower the risk of stroke.