Abstract
BACKGROUND: The recommendation to limit dietary saturated fat intake is primarily drawn from observational studies rather than randomized controlled trials of cardiovascular disease prevention. Thus, we aimed to investigate the efficacy of saturated fat reduction in preventing mortality and cardiovascular diseases. METHODS: In this systematic review and meta-analysis of randomized controlled trials, Cochrane CENTRAL, PubMed, and Ichu-shi databases were searched for articles up to April 2023. Randomized controlled trials on saturated fat reduction to prevent cardiovascular diseases were selected. Cardiovascular and all-cause mortality and cardiovascular outcomes were evaluated. Changes in electrocardiography or coronary angiography findings were excluded because they could be evaluated arbitrarily. Two or more reviewers independently extracted and assessed the data. A random-effects meta-analysis was performed. RESULTS: Nine eligible trials with 13,532 participants were identified (2 were primary and 7 were secondary prevention studies). No significant differences in cardiovascular mortality (relative risk [RR] = 0.94, 95% confidence interval [CI]: 0.75-1.19), all-cause mortality (RR = 1.01, 95% CI: 0.89-1.14), myocardial infarction (RR = 0.85, 95% CI: 0.71-1.02), and coronary artery events (RR = 0.85, 95% CI: 0.65-1.11) were observed between the intervention and control groups. However, owing to limited reported cases, the impact of stroke could not be evaluated. CONCLUSIONS: The findings indicate that a reduction in saturated fats cannot be recommended at present to prevent cardiovascular diseases and mortality. Clinical trials are needed to evaluate the effects of saturated fat reduction under the best possible medical care, including statin administration. SYSTEMATIC REVIEW REGISTRATION NUMBER: This systematic review and meta-analysis was registered with the International Prospective Register of Systematic Reviews (CRD42023428498).