When essential fatty acids are in short supply, the body compensates by substituting other types of fatty acids that have a less supple biochemical structure. As polyunsaturates are replaced by these other compounds, cell membranes become more rigid, leading to progressive hardening of the arterial walls. Polyunsaturated fats should make up 10 percent or less of your total daily calories. They are ?good? fats.
I should also emphasize another type of essential polyunsaturated fat: omega- 3 fatty acids. These are found in fatty fish, like salmon, tuna, and trout, as well as in canola oil and flaxseed. Known as eicosapentaenoic acid, or EPA, and docosahexaenoic acid, or DHA, they help maintain and protect your heart, blood vessels, and brain function. Two fish meals a week will supply you with the right amount of these fats.
Monounsaturated Fatty Acids
Monounsaturated fats come from avocados and olive, canola, and peanut oils, as well as from nuts. For more than thirty- five years, studies have shown that diets containing monounsaturated fats, such as the traditional Mediterranean diet, are good for the heart. These fats can help lower cholesterol, blood pressure, and blood sugar levels.
The Mediterranean diet is moderately high in fat (about 30 percent of fat calories mostly from olive oil) and emphasizes fresh fruits and vegetables, whole grains, legumes, nuts, and a high intake of fish and little red meat. If your HDL (high- density lipoprotein, or ?good?) cholesterol is low (35 or less), add a daily serving or two of canola or olive oil, nuts, avocado, or fatty fish (like salmon). In exchange, subtract a serving or two of sweets or refined bread, pasta, crackers, or cereal.