White meat consumption and risk of cardiovascular disease and type 2 diabetes: a systematic review and meta-analysis

Objectives: The aim was to systematically review the associations among white meat consumption, cardiovascular diseases (CVD), and type 2 diabetes (T2D). Methods: Databases MEDLINE, Embase, and Cochrane Central Register of Controlled Trials and Scopus were searched (15th October 2021) for randomized intervention trials (RCTs, >= 4 weeks of duration) and prospective cohort studies (>= 12 month of follow-up) assessing the consumption of white meat as the intervention/ exposure. Eligible outcomes for RCTs were cardiometabolic risk factors and for cohorts, fatal and non-fatal CVD and incident T2D. Risk of bias was estimated using the Cochrane's RoB2 and Risk of Bias for Nutrition Observational Studies. Meta-analysis was conducted in case of >= 3 relevant intervention studies or >= 5 cohort studies using random-effects models. The strength of evidence was evaluated using the World Cancer Research Fund's criteria. Results: The literature search yielded 5,795 scientific articles, and after screening 43 full-text articles, 23 cohort studies and three intervention studies were included. All included intervention studies matched fat content of intervention and control diets, and none of them showed any significant effects on the selected outcomes of white meat when compared to red meat. Findings from the cohort studies generally did not support any associations between white meat intake and outcomes. Meta-analyses were conducted for CVD mortality (RR: 0.95, 95% CI: 0.87-1.02, P = 0.23, I-2 = 25%) and T2D incidence (RR: 0.98, 95% CI: 0.87-1.11, P = 0.81, I-2 = 82%). Conclusion: The currently available evidence does not indicate a role, beneficial or detrimental, of white meat consumption for CVD and T2D. Future studies investigating potentially different health effects of processed versus unprocessed white meat and substitution of red meat with white meat are warranted. Registration: Prospero registration CRD42022295915.