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Heart supplements: Proceed with caution

Last updated: February 2011

Popping vitamin, mineral, or other dietary supplements might seem like an easy way to boost heart health, but that's usually not the case. A number of large studies over the past several years failed to find that supplements of folic acid and other B vitamins, as well as vitamins C and E, prevent heart attacks or strokes. In one study, in fact, vitamin E was linked to an increased risk of hemorrhagic stroke.

One supplement—red yeast rice—can lower LDL (bad) cholesterol almost as effectively as certain statin drugs. But that's because it can contain a naturally occurring substance essentially identical to the prescription drug lovastatin (Altoprev, Mevacor, and generic). Unfortunately, that means it poses the same risks, too, which can be considerable, especially if you're not being monitored by a doctor.

Moreover, since heart supplements aren't carefully regulated by the Food and Drug Administration, it's often hard to know whether what's on the label is really in the package. Indeed, a study in the Oct. 25, 2010, issue of the Archives of Internal Medicine found "striking" variability in the amount of the active ingredients in 12 red yeast rice supplements. The labels "all said 600 milligrams on the bottle," said Ram Gordon, M.D., a cardiologist at the Chestnut Hill Hospital in Philadelphia and the lead author of the recent study. "The question is, 600 mg of what?" Our medical consultants say people should avoid all red yeast rice supplements.

The evidence for some other heart supplements—such as coenzyme Q-10, garlic and green tea—is often inconsistent or weak. And even those that are more likely to offer benefits can pose some risks, too, especially when taken with certain drugs. Even fish oil, which has good supporting evidence, probably shouldn't be taken with high blood-pressure medication or blood-thinning drugs.

Finally, supplements taken for noncardiac reasons can also interact with certain heart medication. Echinacea, for example, can make statins more potent, possibly increasing the risk of side effects, and St. John's wort can make those drugs less effective. "Many patients on heart drugs don't realize that a number of supplements—no matter what they're taken for—can interfere with how well heart drugs work," Gordon says.

Our advice: Don't take heart supplements without talking with a doctor first, especially if you take heart medication. And supplements should never be used in place of needed medication or as an excuse to skip proven protective measures, such as losing excess weight, exercising more, and eating a heart-healthy diet.

If you do opt for a heart supplement, look for one labeled "USP Verified." That indicates that the manufacturer has voluntarily asked the U.S. Pharmacopeia, a nonprofit, private standards-setting authority, to verify the quality, purity, and potency of its raw ingredients or finished products. For a list of products that have been verified by the USP, go to www.uspverified.org.

Here's our guide to some supplements that are likely to offer some heart-health benefits, according to the Natural Medicines Comprehensive Database, which partners with ConsumerReportsHealth.org to evaluate the safety and effectiveness of supplements. The evidence is especially strong for the first, fish oil. The table below lists some herbs and heart drugs that can sometimes interact in dangerous ways.

Fish oil

The omega-3 fatty acids in fish oil, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), appear to be most effective at lowering triglycerides, an artery-clogging fat in the blood. They might also protect the heart by slightly raising HDL (good) cholesterol, lowering blood pressure, and reducing inflammation.

The American Heart Association says that people with heart disease should consume about a gram (1,000 milligrams) of omega-3s a day, an amount that generally requires taking a supplement. People with high triglyceride levels might need 2 to 4 grams a day from multiple pills or possibly a prescription-strength fish-oil supplement. Others should aim to eat two or more servings of fatty fish a week that are high in omega-3s (and relatively low in mercury), such as wild salmon, mackerel, and sardines. Or they could consider fortified foods or fish-oil pills.

Fish-oil supplements are probably safe for most people when taken in doses of 3 grams or less per day, though they might interact with certain drugs, notably blood thinners. So talk with a doctor first, especially if you take any medication regularly. The supplements can also cause side effects, such as upset stomach and bad breath. Keeping the capsules in the freezer might lessen those effects. And remember to look for "USP Verified" products.

Plant stanols and sterols

Those substances—which occur naturally in nuts, seeds, and whole grains—appear to reduce the amount of cholesterol the body absorbs from food. Manufacturers now add them to other foods, such as Benecol spread. Both are also available as supplements and can lower LDL cholesterol. Some research suggests that one stanol, sitostanol, might lower LDL cholesterol by about 10 to 15 percent, and perhaps boost the effectiveness of statin drugs. Both stanols and sterols can cause side effects, such as diarrhea, and one sterol, beta-sitosterol, has been associated with erectile dysfunction and loss of libido.

Fiber

It's generally best to get fiber—which appears to lower LDL cholesterol, possibly by absorbing fat in the gut—from foods, such as beans, oats, produce, and whole grains. But certain fiber supplements, notably blond psyllium, might also help lower LDL. Don't confuse blond psyllium with black psyllium, which isn't as scientifically proven to help and is more likely to cause choking if taken without adequate fluids. And both supplements might interfere with the absorption of various medications, possibly including diabetes drugs, so talk with a doctor first.

Supplements that can harm the heart

A few supplements can harm the heart directly. Yohimbe, for example, which is sold as a treatment for impotence, has been linked to heart attacks and dangerous increases in heart rate. And some supplements threaten the heart by interacting with medication, especially drugs prescribed for heart-related problems, according to an article in the Feb. 9, 2010, issue of the Journal of the American College of Cardiology. The table below lists some common examples. Talk with your doctor before taking any supplement, not just those listed below, especially if you take any medication regularly.

Dangerous herb and heart-drug interactions

Herb Heart-related drug* Potential dangerous interaction
Alfalfa Warfarin (Coumadin), to prevent blood clots Bleeding
Aloe vera Digoxin (Lanoxin), to treat heart failure due to an abnormal heart beat Increased potency, possibly making side effects such as nausea, vomiting, and dangerously slow heart beat more likely
Danshen Aspirin, clopidogrel (Plavix), or warfarin (Coumadin) Bleeding
  Digoxin (Lanoxin) Increased potency, possibly making side effects such as nausea, vomiting, and dangerously slow heart beat more likely
Echinacea Amiodarone (Cordarone), for abnormal heart rhythms Dangerous change in EKG
  Fibrates, niacin, and statins to lower LDL (bad) cholesterol or triglyceride levels Liver damage
Garlic Aspirin, clopidogrel (Plavix), heparin, or warfarin (Coumadin) Bleeding
Ginkgo biloba Aspirin, warfarin (Coumadin) Bleeding
Ginseng Digoxin (Lanoxin) Interferes with blood tests for digoxin
  Warfarin (Coumadin) Decreased effectiveness of warfarin
Hawthorn Calcium-channel blockers such as diltiazem (Cardizem) and nifedipine (Procardia), and nitrates, such as isosorbide (Isordil) Increased potency, possibly making side effects more likely
  Digoxin (Lanoxin) Increased potency, possibly making side effects such as nausea, vomiting, and dangerously slow heart beat more likely
Licorice Spironolactone (Aldactone), used for high blood pressure and heart failure Low potassium levels
Saw palmetto Aspirin, clopidogrel (Plavix), or warfarin (Coumadin) Bleeding
Soy milk Warfarin (Coumadin) Decreased effectiveness of warfarin
St. John’s wort Amiodarone (Cordarone), simvastatin (Zocor), and warfarin (Coumadin) Decreased effectiveness of amiodarone, simvastatin, and warfarin
  Clopidogrel (Plavix) Bleeding
  Digoxin (Lanoxin) Decreased blood levels of digoxin
Yohimbe ACE inhibitors, such as captopril (Capoten) and lisinopril (Prinivil, Zestril), for high blood pressure and heart failure Decreased effectiveness of ACE inhibitors and beta-blockers
  Beta-blockers, such as atenolol (Tenormin) and metoprolol (Lopressor, Toprol) Increased heart rate with beta- blockers
* Editor's Note: Many of the listed drugs are also available as generics.

Source: Adapted from the Journal of the American College of Cardiology, Feb. 9, 2010.

This report was made possible by a grant from the Airborne Cy Pres Fund, which was established through a legal settlement of a national class-action lawsuit (Wilson v. Airborne Health, Inc., et al.) regarding deceptive advertising practices.
   

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