In light of a recent review questioning the link between saturated-fat intake and heart disease (May 2010 Healthlet-ter), another new meta-analysis suggests the key to heart health may be what you eat instead of saturated fats. If you replace saturated fats such as butter with processed carbohy-drates, you may be no better off. But replacing saturated fats with polyunsaturated fats such as those in liquid vegetable oils reduced the risk of a coronary heart disease-related event by 19%.Dariush Mozaffarian, MD, of Harvard University, and colleagues noted that reducing saturated fat intake has long been recommended to prevent heart disease. But the benefits of saturated-fat reduction, they added, are surprisingly poorly established in randomized controlled trials.Dr. Mozaffarian and colleagues pooled the results of eight prior randomized controlled trials that were mostly too small or otherwise underpowered to detect signifi-cant benefits from such a fat switch. The combined studies totaled 13,614 participants. Average intake of polyunsatu-rated fats in the studies control groups was 5% of total calories, while those in intervention groups told to boost intake averaged 14.9%.Overall, the combined results showed that those who substituted polyunsaturated for saturated fats were 19% less likely to suffer a coronary heart disease-related event. For each 5% increase in polyunsaturated fat intake, risk fell 10%. Total cholesterol levels also fell in the polyunsaturated fat groups by an average of 29 mg/dL. Longer-duration studies showed even greater benefits, indicating that the benefits of increasing polyunsaturated fatty acid consumption accrue over time.The researchers concluded, The pooled results demon-strate a significant benefit of replacing polyunsaturated fatty acids for saturated fats on clinical coronary heart disease events. They characterized the findings as only the second dietary intervention (after omega-3s in fish oil) clearly demonstrated to reduce cardiovascular events in randomized controlled trialThe best strategy for such a dietary change, Dr. Mozaffar-ian and colleagues suggested, would be to replace saturated fats (such as butter and other fats solid at room temperature) with vegetable oils containing n-3 polyunsaturated fat, such as soybean or canola oil. High levels of polyunsaturated fat intake appear to be safe, the researchers added, calling into question the current recommendation to limit polyunsatu-rated fats to 10% of calories.TO LEARN MORE: PLoS Medicine,dx.doi.org/10.1371/journal.pmed.1000252.
