Saturated fat is (still) out and polyunsaturated fat (PUFA) is in, according to a new report from the American Heart Association (AHA). In a Presidential Advisory, the organization stated in the strongest possible terms that replacing dietary saturated fat with PUFA reduces risk for heart disease. According to the AHA, the evidence in support of this dietary change has strengthened over the years.
Although some studies have failed to find that reducing saturated fat intake lowers heart disease risk, this is largely because of a failure to look at what replaces saturated fat. Replacing saturated fat with refined carbohydrates does not lower heart disease risk. However, replacing it with healthful fats such as monounsaturated fat and PUFA lowers both LDL-cholesterol and heart disease risk.
In stating their conclusions, the AHA pointed to a meta-analysis of four core clinical trials which found that replacing saturated fat with PUFA reduced risk by a statistically significant 29%. Soybean oil was the sole replacement in one of the trials and was a main source of PUFA in two others. (In the fourth trial the source of PUFA was described only as “vegetable oil,” which may have been soybean oil).
Other major findings of the AHA advisory include the following:
- Evidence is more supportive of replacing saturated fat with PUFA than with monounsaturated fat to reduce CHD risk
- Replacing saturated fat with either PUFA or monounsaturated fat lowers blood triglyceride levels, an independent biomarker of risk for cardiovascular disease
- Replacing saturated fat with either PUFA or monounsaturated fat reduces the concentration all LDL particle sizes although findings for this effect are limited
- Coconut oil is not recommended since it increases LDL-cholesterol and has no known offsetting favorable effects
The AHA advisory is clearly intended to address much of the misinformation and confusion about the relationship of dietary fat to CHD that has been so prevalent in recent years. This advisory should help emphasize the important role that healthful fats, such as soybean oil can play in reducing CHD risk.