Also: Fiber-rich diet may lower colon cancer risk. Grapefruit juice and statins

April 30, 2015 April 30, 2015 Dietary supplements for cholesterol: Are any worth a try? Various herbs and other supplements have been touted for their ability to improve cholesterol levels. Here's what the research shows — and doesn't show — about some of the best-known products. Hawthorne. The leaves, berries, and flowers of this plant are used to make medicine that was traditionally used to treat cardiovascular diseases. It may lower cholesterol by increasing the excretion of bile and decreasing the body's production of cholesterol. Verdict: It may possibly help. Get your copy of Managing Your Cholesterol Managing Your Cholesterol offers up-to-date information to help you or a loved one keep cholesterol in check. The report spells out what are healthy and unhealthy cholesterol levels, and offers specific ways to keep cholesterol in line. It covers cholesterol tests and the genetics of cholesterol. The report also focuses on treatments based on the latest scientific evidence, including the pros and cons of statins and other medications, and provides the lowdown on other substances advertised to lower cholesterol. Managing Your Cholesterol can also help you work with your doctor to individualize your treatment. Red yeast rice. This Chinese medicine has been marketed in the United States as a supplement that's said to lower cholesterol levels. Some red yeast rice products contain a chemical that's identical to the active ingredient in lovastatin. But an independent analysis of 12 red yeast rice products found that although all claimed to have 600 milligrams (mg) of the active ingredient in each capsule, the actual content varied between 0.1 mg and 10.9 mg. In addition, one-third of the products were contaminated with a potentially toxic compound called citrinin, which can cause kidney failure. This cautionary tale illustrates the potential pitfalls of taking dietary supplements, which are virtually free of the testing and manufacturing requirements that apply to pharmaceutical drugs. Verdict: It may possibly help, but purity remains a problem. Garlic. Some preliminary studies suggested that garlic might lower blood cholesterol levels slightly. But one study on the safety and effectiveness of three garlic preparations (fresh garlic, dried powdered garlic tablets, and aged garlic extract tablets) found no effect on cholesterol levels. Verdict: Save your money. Fish oil. Oil from fatty fish such as salmon and sardines contains omega-3 fatty acids. Omega-3s have several heart-healthy effects: they lower heart rate and blood pressure and improve the health of blood vessels. Several studies have shown that eating fatty fish lowers heart risks for people with heart failure or a previous heart attack. Fish oil might not have the same impact, however. A 2013 study in The New England Journal of Medicine found that fish oil supplements don't lower heart attack or stroke risk in people at high risk of heart disease. High doses of fish oil can lower triglycerides, but at the same time, they cause a small increase in LDL (the "bad" cholesterol). Verdict: Eat fish instead. To learn more about the use of supplements for improving cholesterol levels, their effectiveness, and how they affect you, buy Managing Your Cholesterol, a Special Health Report from Harvard Medical School.  Share this story: News and Views from the Harvard Health Blog Switching to a fiber-rich diet may lower colon cancer risk in blacks Switching from a "Western" diet with lots of fat and meat to a fiber-rich diet for just two weeks makes conditions in the large intestine less favorable to the development of colon cancer. The opposite switch may promote the formation of cancer. Grapefruit juice and statins Q. I've heard that people shouldn't drink grapefruit juice if they're taking a statin. Why? A. Certain classes of drugs — most notably statins — are metabolized (broken down) in your intestines by an enzyme called CYP3A, which normally reduces the amount of drug that enters your bloodstream. Grapefruit juice contains compounds called furanocoumarins that stop CYP3A from doing its job. As a result, more of the drug is absorbed, making it more powerful than it's meant to be — even toxic in some cases. Not all statins are affected equally by grapefruit juice, so grapefruit fans might want to switch to a statin that's less affected (see the table below). But if you can't switch, experts say it's probably okay to enjoy a small glass. That's because the studies showing dangerous effects used massive amounts of furanocoumarins, the amount found in a quart or more of the juice. What's more, eating half a grapefruit is even less risky than drinking grapefruit juice, since it takes several fruits to make a single glass of juice. But to be on the safe side, check with your doctor, and avoid taking your pills with grapefruit juice. The grapefruit effect: Grapefruit juice affects certain statins more than others Big effect Little or no effect atorvastatin (Lipitor) fluvastatin (Lescol) lovastatin (Mevacor) pitavastatin (Livalo) simvastatin (Zocor) pravastatin (Pravachol)   rosuvastatin (Crestor) To learn more about cholesterol medications and how they can affect you, buy Managing Your Cholesterol, a Special Health Report from Harvard Medical School. Share this story: Featured in this issue Managing Your Cholesterol Featured content: • Cholesterol in the body • The cholesterol connection • What causes heart disease • Why treat cholesterol? • Your cholesterol test •  ... and more! 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