Approximately 13 percent of U.S. adults has high total cholesterol. Lowering cholesterol levels can slow down, reduce, or even stop plaque from building up in the walls of arteries and may decrease the chance of having a heart attack. Mainstays in treating high cholesterol include diet, weight loss, physical activity, and when necessary, drug treatment.

National survey data show that high blood cholesterol is one of the top 10 conditions for which people use complementary health practices such as dietary supplements.

Here’s what you should know if you have high blood cholesterol:

1. Work with your health care provider. Ask your health care provider about proven steps you can take to lower your blood cholesterol levels. And be sure to talk with your provider about any complementary health practice you are considering, including dietary supplements. This will help ensure safe and coordinated care.
   
2. Change your diet. Saturated fat raises your LDL cholesterol level (often called "bad cholesterol," the main source of cholesterol buildup and blockage in the arteries) more than anything else in your diet. Diets with too much saturated fat and trans fat are the main cause for high blood cholesterol.
   
3. Manage your weight. Losing extra pounds may help lower your LDL and triglycerides (a type of fat found in the blood and in food), while raising your HDL (often called "good cholesterol," helps keep cholesterol from building up in the arteries).
   
4. Get moving. Regular physical activity (such as brisk walking 30 minutes each day) can raise HDL and lower triglycerides, and can help you lose weight and, in that way, help lower your LDL. Aim for a total of at least 150 minutes over the course of a week.
   
5. Find out what the science says about dietary supplements marketed for improving cholesterol. The dietary supplements red yeast rice, flaxseed, and garlic, are among the many supplements that have been studied for lowering cholesterol levels. Unfortunately, there isn’t conclusive evidence that any of these supplements are effective in reducing cholesterol levels.
   • Red yeast rice. Some red yeast rice products contain substances called monacolins, which are produced by the yeast. Monacolin K is chemically identical to the active ingredient in the cholesterol-lowering drug lovastatin, and can cause the same types of side effects and drug interactions as lovastatin. Other red yeast rice products contain little or no monacolin K, and it is not known whether these products have any effect on cholesterol levels. Unfortunately, there is no way to know how much monacolin K is present in most red yeast rice products. Further, the U.S. Food and Drug Administration has determined that red yeast rice products that contain more than trace amount of monacolin K cannot be sold legally as dietary supplements.
     
   • Flaxseed. Studies of flaxseed preparations to lower cholesterol levels report mixed results. A 2009 review of the scientific research of flaxseed for lowering cholesterol found modest improvements in cholesterol, seen more often in postmenopausal women and in people with high initial cholesterol concentrations.
     
   • Garlic. Some evidence indicates that taking garlic supplements can slightly lower blood cholesterol levels; however, an NCCAM-funded study on the safety and effectiveness of three garlic preparations (fresh garlic, dried powdered garlic tablets, and aged garlic extract tablets) for lowering blood cholesterol levels found no effect. Although garlic supplements appear to be safe for most adults, they can thin the blood in a manner similar to aspirin, so use caution if you are planning to have surgery or dental work. Garlic supplements have also been found to interfere with the effectiveness of saquinavir, a drug used to treat HIV infection.