Effects on coronary heart disease of increasing polyunsaturated fat in place of saturated fat: a systematic review and meta-analysis of randomized controlled trials.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 20351774 · doi:10.1371/journal.pmed.1000252
What was done
The authors conducted a systematic review and random-effects meta-analysis of randomized controlled trials identified through June 2009 across multiple databases, grey literature, and expert contacts. Eligible trials randomized participants to increased polyunsaturated fat (PUFA) in place of saturated fat (SFA) for at least 1 year without major concomitant interventions, included an appropriate control group, and reported hard coronary heart disease (CHD) endpoints (myocardial infarction or cardiac death). Study selection and data extraction were performed independently and in duplicate.
What was found
Eight randomized trials met inclusion criteria, totaling 13,614 participants and 1,042 CHD events. Average weighted PUFA intake was 14.9% of energy (range 8.0%–20.7%) in intervention groups versus 5.0% of energy (range 4.0%–6.4%) in controls. PUFA consumption in place of SFA reduced CHD risk by 19% (RR = 0.81, 95% CI 0.70–0.95, p = 0.008), corresponding to a 10% risk reduction for each 5% energy increase in PUFA (RR = 0.90, 95% CI 0.83–0.97), with moderate, non-significant heterogeneity (I² = 37%, p = 0.13). Meta-regression showed study duration was an independent determinant of risk reduction (p = 0.017), with longer studies showing greater benefit.
Why it matters
This meta-analysis provides trial evidence that replacing saturated fats specifically with polyunsaturated fats reduces hard coronary events, supporting dietary guidance focused on replacement nutrient quality.
Limits
Only eight trials met inclusion criteria. The abstract does not report data on specific PUFA subtypes (such as omega-3 versus omega-6 fatty acids), all-cause mortality, dietary adherence over time, or adverse effects.
Cited by
- supports Meta-analyses of the longest, lowest-dropout randomized controlled trials replacing saturated fats with polyunsaturated fats show a reduction in cardiovascular events.