Nutrition Key to Lower Cholesterol
Low-fat diets that include plenty of fruits, vegetables, whole grains, and legumes may help lower cholesterol levels more effectively than simply restricting fat intake, reports the Annals of Internal Medicine (2005;142:725–33).
Cholesterol, a component of cell membranes, is a building block for the synthesis of steroid hormones and is necessary for the normal functioning of the body. However, elevated cholesterol levels in the body increase the risk of cardiovascular disease.
Cholesterol is derived from the diet and is also manufactured in the body by the liver. Lipoproteins transport cholesterol in the blood to various tissues and organs. Low-density lipoprotein (LDL) is the major carrier of cholesterol. High levels of LDL cholesterol can cause damage to the blood vessels, leading to hardening of the arteries (atherosclerosis); when this occurs in the arteries supplying the heart or brain, the chance of suffering a heart attack or stroke increases. LDL cholesterol is often called “bad” cholesterol.
High-density lipoprotein (HDL), on the other hand, picks up cholesterol from circulation and transports it back to the liver to be excreted from the body. High levels of HDL cholesterol are considered protective against heart disease, earning it the nickname, “good” cholesterol.
The American Heart Association recommends limiting saturated fat and cholesterol intake to help lower cholesterol levels. In 2000, the American Heart Association released new guidelines for lowering cholesterol that emphasized eating more vegetables and whole grains in addition to keeping fat intake low.
The new study investigated this recommendation by comparing the effects of two different low-fat diets on cholesterol levels in 120 people with high cholesterol. The participants (average age 48) were assigned to either a standard low-fat diet (LF) or a low-fat “plus” diet (LFP) for four weeks. Each diet provided 30% of calories from fat (10% from saturated fat) and 100 mg of cholesterol per 1,000 calories consumed per day. Protein and carbohydrate intakes were also identical between the diets.
The LF diet consisted primarily of prepackaged convenience foods such as instant oatmeal, frozen entrees, processed meats, white bread, snack crackers, and cookies. The LFP diet emphasized whole grains like brown rice and millet; fruits such as blueberries, grapes, and oranges; beans; nut and seed butters; and a variety of vegetables. The LFP diet also included about 1.5 cloves of garlic and 16 grams (about half an ounce) of soy protein per 2,000 calories. To match fat and cholesterol intakes between the groups, cheese, butter, and eggs were added to the LFP diet.
Levels of total, LDL, and HDL cholesterol, and triglyceride levels were measured at the beginning and end of the study to assess the response to each diet. The LFP diet resulted in significantly greater decreases in total and LDL cholesterol levels than did the LF diet. Total cholesterol fell by about 18 mg/dL in the LFP group, compared with a 9 mg/dL drop in the LF group. LDL cholesterol levels decreased by 14 mg/dL in the LFP group and by 7 mg/dL in the LF group. HDL cholesterol and triglyceride levels did not differ substantially between the groups.
Because the diets were identical in fat and cholesterol content, these results suggest that other components of the LFP diet must have been responsible for the cholesterol-lowering effect. These findings are similar to those from other studies that have shown that including certain foods such as soy, oats, okra, eggplant, nuts, and plant sterols can reduce cholesterol levels when consumed as part of a low-fat diet.
Kimberly Beauchamp, ND, received her bachelor’s degree from the University of Rhode Island and her Doctorate of Naturopathic Medicine from Bastyr University in Kenmore, WA. She is a co-founder and practicing physician at South County Naturopaths, Inc., in Wakefield, RI. Dr. Beauchamp teaches holistic medicine classes and provides consultations focusing on detoxification and whole-foods nutrition.
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