Vegetarian, Vegan Diets And Multiple Health Outcomes: A Systematic Review With Meta-Analysis Of Observational Studies, Critical Reviews in Food Science and Nutrition, 6 February 2016
They included 96 studies: 86 cross-sectional and 10 prospective cohort:
The overall analysis among cross-sectional studies reported significant reduced levels of body mass index, total cholesterol, LDL-cholesterol, and glucose levels in vegetarians and vegans versus omnivores. With regard to prospective cohort studies, the analysis showed a significant reduced risk of incidence and/or mortality from ischemic heart disease (RR 0.75; 95% CI, 0.68 to 0.82) and incidence of total cancer (RR 0.92; 95% CI 0.87 to 0.98)
The analysis conducted among vegans reported significant association with the risk of incidence from total cancer (RR 0.85; 95% CI, 0.75 to 0.95).
Conclusions: This comprehensive meta-analysis reports a significant protective effect of a vegetarian diet versus the incidence and/or mortality from ischemic heart disease (−25%) and incidence from total cancer (−8%). Vegan diet conferred a significant reduced risk (−15%) of incidence from total cancer.
The body of evidence favoring plant-based diets continues to grow.