Although people tend to consider cholesterol a harmful substance, it is essential for the health of cell membranes. It is not necessary in the diet, however, because the liver produces cholesterol from various nutrients. Cholesterol levels may become elevated when people eat too many foods containing cholesterol as well as high amounts of triglyceride fats and sugary foods that convert to triglycerides. Changing your diet can help lower cholesterol, according to MayoClinic.com.
Effects
When cholesterol levels in the blood exceed what is considered normal, some cholesterol remains in the arteries and hardens over time, explains Frank W. Jackson, M.D., at the Jackson Siegelbaum Gastroenterology website. Cholesterol plaque builds up on the interior artery walls, which narrows arteries and decreases -- or even blocks -- blood flow. A stroke occurs when blood flow to the brain is blocked, and angina or a heart attack may occur when plaque blocks a coronary artery.
Foods to Avoid
To lower cholesterol through diet, reduce your intake of cholesterol and fat, particularly saturated and trans fats, advises MayoClinic.com. Saturated fats occur in meat, poultry, fish and full-fat dairy products, while trans fats are found in some stick margarines and commercial snack products such as cookies and crackers. Trans fats not only increase low-density lipoprotein cholesterol or LDL, the so-called bad cholesterol, but they decrease levels of high-density lipoprotein cholesterol or HDL, the good cholesterol. Meat, poultry, fish and whole-milk products also contain cholesterol, as do egg yolks.
Foods to Include
Eating nuts -- especially walnuts, almonds, hazelnuts, pecans, pine nuts pistachio nuts and peanuts -- can decrease cholesterol levels, according to MayoClinic.com. Soluble fiber in the diet, such as oats, also can lower cholesterol. In addition, olive oil contains antioxidants that can reduce cholesterol, so use 2 tbsp. a day instead of other fats in your diet. Plant sterols and stanols are helpful, because they block some absorption of cholesterol. Some brands of margarine and orange juice are fortified with these substances. Soy protein is another good choice. Dr. Jackson recommends eating oily fish at least three times per week. Although oily fish contains some cholesterol, its omega-3 fatty acids helps lower cholesterol and provides other health benefits as well. Some examples of these fish include albacore tuna, mackerel, salmon and walleye.
Tips
Because nuts are high in calories, eat only a handful per day, and substitute them for other foods high in saturated fat, advises MayoClinic.com. Top your salad with walnuts or almonds, for instance, rather than with cheese or meat. Add olive oil to your diet by using it for salad dressing or including it in a marinade. Drinking two 8-oz. glasses per day of orange juice fortified with plant sterols provides enough to significantly lower cholesterol.
Research
A study led by David J.A. Jenkins and published in the July 23, 2003, issue of the "Journal of the American Medical Association" investigated the effectiveness of diet in lowering cholesterol. All three groups evaluated had significant reductions in cholesterol levels after one month. They included participants eating a diet very low in saturated fat, the same diet plus the cholesterol-reducing medication lovastatin, and a diet with a portfolio of plant sterols, viscous fiber, almonds and soy protein. The low-fat diet group had an 8 percent reduction in cholesterol, the portfolio diet group a 28.6 percent reduction and the diet-plus-statin group 30.9 percent reduction.
