Reduction in saturated fat intake for cardiovascular disease

Area of Science:

• Nutritional Science
• Cardiovascular Health
• Dietary Interventions

Background:

• Reducing saturated fat intake is known to lower serum cholesterol.
• The impact of replacing saturated fats with other macronutrients (polyunsaturated fats, monounsaturated fats, carbohydrates, or protein) on health outcomes requires clarification.
• This review updates previous findings on dietary fat modification.

Purpose of the Study:

• To evaluate the effects of reducing saturated fat and replacing it with carbohydrates, polyunsaturated fats, monounsaturated fats, or protein on mortality and cardiovascular morbidity.
• To synthesize evidence from all available randomized clinical trials on this dietary intervention.

Main Methods:

• Systematic search of Cochrane CENTRAL, MEDLINE, and EMBASE databases up to March 2014.
• Inclusion of randomized controlled trials (RCTs) with interventions lasting at least 24 months, focusing on adults, and reporting mortality or cardiovascular morbidity data.
• Random-effects meta-analyses, meta-regression, subgrouping, and sensitivity analyses were performed on extracted data from 15 RCTs (approximately 59,000 participants).

Main Results:

• Reducing dietary saturated fat was associated with a 17% reduction in cardiovascular events (Risk Ratio [RR] 0.83; 95% Confidence Interval [CI] 0.72 to 0.96).
• Effects on all-cause mortality (RR 0.97; 95% CI 0.90 to 1.05) and cardiovascular mortality (RR 0.95; 95% CI 0.80 to 1.12) were less clear.
• Cardiovascular event reduction was observed when saturated fat was replaced by polyunsaturated fats; no significant effects were noted with carbohydrate or protein replacement. Evidence for monounsaturated fat replacement was limited.

Conclusions:

• Reducing saturated fat intake may lead to a small but significant decrease in cardiovascular risk.
• Replacing saturated fat with polyunsaturated fats appears to be a beneficial strategy for cardiovascular health.
• Continued lifestyle advice should emphasize saturated fat reduction and partial replacement with unsaturated fats for cardiovascular disease prevention.