The 2010 Dietary Guidelines for Americans (DGA) recommended that saturated fat consumption should be limited to 10% of the diet. The 10% limit has remained unchanged since it was first introduced 20 years ago by the 1990 DGA and does not appear to be a primary dietary health concern. The 2010 DGA noted that the current dietary intake level for saturates is approximately 11%, only slightly higher than the target of 10%. But DGA also suggested that reducing saturated intake lower than 10% may be beneficial to reducing the risk of heart disease, but only if substituted by unsaturated fat. This implies that simply lowering saturated fat intake or substitution of saturates with carbohydrates will not provide any health benefit. Apparently, saturated fat is not as bad as it was once thought to be.
Outdated science is likely to blame for the exaggerated representation of saturated fat as a major contributor to heart disease for the previous 50 years, according to Gerald McNeill, PhD, director of R&D at Loders Croklaan North America, IOI Group, Channahon, IL.
“The basis for this recommendation was the diet-and-heart hypothesis of the 1950s through the 1970s,” Dr. McNeill said. “Early data from the Seven Counties Study appeared to show a relationship between dietary fat, serum cholesterol and heart disease. But since then, more research has been done that produced more reliable results. As for the actual effect on heart disease, the 2006 Women’s Health Initiative study followed 40,000 people for nine years and found essentially no difference in risk by replacing saturated fat with unsaturated fat. The Nurses Health Study of 2005 involved 120,000 people over 20 years. Again, consumption of saturated fat showed essentially no effect on risk.”
In contrast, he added, “Two meta-analyses published in the American Journal of Clinical Nutrition within the last 18 months have specifically stated that there is no proven, direct causal link between saturated fat and cardiovascular disease, and it is only polyunsaturated fat that has a positive impact.”
When considering the influence of fats in the diet with serum cholesterol in humans, an interesting paradox occurs. Saturated fats increase low-density-lipoprotein (LDL) cholesterol, the “bad” form, and unsaturated fats lower that risk; however, saturated fats increase high-density-lipoprotein (HDL) cholesterol, the “good” form. Even so, it turns out that science proves the biggest overall risk factor in formation of serum cholesterol to be genetic, not dietary.
Dr. McNeill said that the early research into the dietary effects of saturated fats and its claims about negative effects on heart health have become entrenched in the conventional thinking about these fats and health. Instead, he said, “Eat as much saturated fat as you want.”