You’ve been hearing the message for years: For a healthy heart, you must cut back on butter, whole milk, juicy meats, and other saturated fat-packed foods. The logic: Eating saturated fat increases “bad” LDL cholesterol and leads to cardiovascular disease. But in recent years, a few researchers have pointed to an inconvenient truth: Some scientific studies have failed to show that curbing our intake of saturated fat prevents heart attacks.
But don’t start making that bacon-and-cheese sandwich just yet. As researchers looked closer at these studies, they discovered that simply eating less saturated fat isn’t the whole solution: how you replace those calories matters. In other words, cutting back on excessive amounts of saturated fat won’t make you healthier if you replace it with foods such as white bread, white rice, and other high-glycemic carbohydrates, which raise triglycerides, lower “good” HDL cholesterol, and create other problems in the cardiovascular system.
Meanwhile, there is good evidence that replacing some saturated fat with unsaturated fat (MUFAs and PUFAs) will slash your risk for heart attacks, strokes, and other cardiovascular problems.
Trans Fats: Heart Stoppers and Belly Busters
Doctors may debate which form of fat—MUFAs or PUFAs—is best for your heart, but there’s no disagreement over which one is worst. Trans fats are by far the most dangerous form of fat for the cardiovascular system. Some experts estimate that if these bad fats suddenly disappeared, the number of heart attacks worldwide would drop by 20 percent almost overnight.
Furthermore, disturbing new research suggests that trans fats may even be a major hidden cause of obesity.
A tiny amount of trans fat–representing 0.5 percent of calories or less in most diets—occurs naturally in dairy foods, beef, lamb, and some other meats. (And at least one study found that naturally occurring trans fats don’t increase the risk for heart disease.) But the overwhelming source of trans fat in most diets is partially hydrogenated vegetable oil, which is vegetable oil that has been treated to give it a semisolid texture. Partially hydrogenated vegetable oil offers foods a longer shelf life, which is one reason it is common in processed foods. Your heart, however, doesn’t. Here’s a short list of problems trans fats can cause:
• High levels of “bad” LDL cholesterol especially small, dense LDL particles that appear to be especially damaging
• Low levels of “good HDL cholesterol
• Elevated triglycerides, a dangerous type of blood fat
• High levels of Lp(a) lipoprotein, a molecule in the blood that may increase the risk for heart attacks
Some studies suggest that trans fats spark chronic inflammation in the body and cause damage to the lining of blood vessels. It’s no wonder that researchers estimate that widespread cutbacks on trans fat could prevent about one in five heart attacks.