Substitution of animal-based with plant-based foods on cardiometabolic health and all-cause mortality: a systematic review and meta-analysis of prospective studies.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of prospective observational cohort studies
PubMed 37968628 · doi:10.1186/s12916-023-03093-1
What was done
A systematic review and random-effects meta-analysis was conducted searching MEDLINE, Embase, and Web of Science through March 2023 for prospective cohort studies examining dietary substitutions of animal-based foods with plant-based foods on cardiovascular disease (CVD), type 2 diabetes (T2D), and all-cause mortality. Summary hazard ratios (SHRs) and 95% confidence intervals (CIs) were computed, and certainty of evidence was rated using GRADE.
What was found
The analysis included 37 publications across 24 cohorts. Moderate certainty of evidence was observed for lower CVD risk when replacing processed meat with nuts (SHR 0.73, 95% CI 0.59–0.91, n=8 cohorts), legumes (SHR 0.77, 95% CI 0.68–0.87, n=8), or whole grains (SHR 0.64, 95% CI 0.54–0.75, n=7); eggs with nuts (SHR 0.83, 95% CI 0.78–0.89, n=8); and butter with olive oil (SHR 0.96, 95% CI 0.95–0.98, n=3). For T2D incidence, moderate certainty inverse associations were found for replacing red meat with whole grains (SHR 0.90, 95% CI 0.84–0.96, n=6) or nuts (SHR 0.92, 95% CI 0.90–0.94, n=6); processed meat with nuts (SHR 0.78, 95% CI 0.69–0.88, n=6); poultry with whole grains (SHR 0.87, 95% CI 0.83–0.90, n=2); and eggs with nuts (SHR 0.82, 95% CI 0.79–0.86, n=2) or whole grains (SHR 0.79, 95% CI 0.76–0.83, n=2). All-cause mortality was significantly reduced when substituting nuts for red meat (SHR 0.93, 95% CI 0.91–0.95, n=9), processed meat (SHR 0.79, 95% CI 0.71–0.88, n=9), dairy (SHR 0.94, 95% CI 0.91–0.97, n=3), and eggs (SHR 0.85, 95% CI 0.82–0.89, n=8), as well as substituting legumes for processed meat (SHR 0.91, 95% CI 0.85–0.98, n=9) and eggs (SHR 0.90, 95% CI 0.89–0.91, n=7), or whole grains for red meat (SHR 0.96, 95% CI 0.95–0.98, n=3).
Why it matters
This review provides quantitative estimates of the cardiometabolic and survival benefits of specific food-for-food substitutions, identifying nuts, legumes, and whole grains as effective replacements for red meat, processed meat, and eggs in dietary guidelines.
Limits
Findings rely entirely on observational prospective cohorts, making them vulnerable to residual confounding by healthy lifestyle factors and dietary self-report errors. Several specific substitution analyses relied on very small numbers of cohorts (e.g., n=2 or n=3), limiting statistical power and generalizability for those specific comparisons.
Cited by
- supports Large-scale meta-analyses and long-term studies show that plant-based diets generally yield better health outcomes than animal-heavy diets.