High Cholesterol: Nutritional Considerations

Reducing saturated fat and cholesterol intake decreases cholesterol. Cholesterol is present only in foods of animal origin, and these products are often the primary source of saturated fat in a person’s diet. Thus, a diet that reduces or eliminates these products lowers total and LDL cholesterol and triglycerides. Further, adding foods that reduce cholesterol production within the body or that cause cholesterol to be excreted from the body also reduces cholesterol levels.

The key nutritional interventions are as follows:

• Reducing dietary saturated fat and cholesterol: Following a diet low in saturated fat and total fat and replacing saturated fat with unsaturated fat will lower cholesterol levels. The NCEP recommends a diet of less than 7 percent of calories from saturated fat and less than 200 milligrams/day of cholesterol. However, such a diet typically lowers LDL by only about 5 percent, which may not be enough to achieve blood cholesterol goals.
  
  More substantial diet changes appear to produce better results. Vegetarian (especially vegan) diets that are free of cholesterol and very low in saturated fat reduce LDL cholesterol by 17 to 40 percent, with the strongest effects seen when the diet is combined with exercise. Reducing total fat, saturated fat, and cholesterol intake also lowers triglyceride levels by approximately 20 percent.
  
  Although some authorities recommend replacing saturated fat and/or trans fatty acids with monounsaturated and polyunsaturated fats, it is important to remember that all oils are mixtures containing varying amounts of saturated fat. For example, olive oil is approximately 13 percent saturated fat, and fish oils range from 15 to 30 percent saturated fat.
  
  For maximal lipid lowering, all fats and oils should be greatly limited. Greater fat intake leads to weight gain, and many patients with hyperlipidemia need to lose excess weight to prevent cardiovascular disease. Diets very low in fat are an essential component of interventions that may reverse atherosclerotic lesions. Consuming small amounts of fats in their naturally occurring form (e.g., nuts) may be preferable to using oils because of their potentially cardioprotective nutrients: magnesium, fiber, vitamin E, and flavonoids.  
• Increasing soluble fiber: Soluble fiber lowers serum cholesterol, decreasing cholesterol absorption from the gut. Fiber also lowers post–meal insulin levels and produces short–chain fatty acids; both of these effects decrease cholesterol production. At an intake of 8 grams per day, fiber has been shown to lower total cholesterol. Common sources include oats, barley, legumes, and many fruits and vegetables.
• Using foods with specific cholesterol–lowering effects: Eating a variety of foods with cholesterol–lowering effects compares favorably with drug therapy for lowering cholesterol. Diets that combine soluble fiber, soy protein, plant sterols, and nuts have been shown to lower LDL by nearly 30 percent in short–term clinical trials, an effect similar to that of statins. Although each of these foods alone contributes to lowering lipids, their effects are improved when the foods are combined.
• Plant sterol products: Plant sterols (often in the form of margarine) reduce LDL cholesterol by roughly 10 percent by inhibiting cholesterol absorption.
• Soy products: Soy protein reduces cholesterol produced by the liver. In clinical tests, soy protein decreased total cholesterol by 9 percent, LDL by 13 percent, and triglycerides by 10 percent.
• Nuts: Almonds, peanuts, pecans, and walnuts appear to have cholesterol–lowering effects, apparently due to their fiber, plant sterol, and unsaturated fat content. Walnuts, for example, lowered total cholesterol by 12 percent and LDL cholesterol by 16 percent.
• Avoiding alcohol: Avoiding alcohol may help reduce triglycerides. Alcohol appears to raise triglycerides by 5 to 10 mg/dL. Restricting its consumption joins diet, exercise, and weight loss as cornerstones of treatment for patients with elevated triglyceride levels.