Studies show that taking aspirin daily can lower heart attack risk by 33% and reduce your combined risk for heart attack, stroke and cardiovascular death by 15%.

Despite these well-established cardiovascular benefits, doctors disagree on the optimal dose of aspirin-about 60% favor one 81 milligrams (mg) dose daily often referred to as "low-dose" or baby aspirin), while about 35% recommend 325 mg daily (a standard-sized tablet).

What's new: At the University of Kentucky, researchers analyzed 11 major clinical trials comparing different aspirin doses in 10,000 patients with cardiovascular disease (CVD) and found that 75 mg to 81 mg daily prevents heart attacks and strokes as well as higher-dose (325 mg) aspirin does—in some cases, even better—with fewer reports of gastrointestinal bleeding.

How Aspirin Works

Aspirin helps guard against heart attack and stroke by inhibiting the effects of cyclooxygenase-1 (COX-1), an enzyme that blood platelets require for coagulation (clotting). Aspirin's effect on this enzyme helps prevent the formation of clots that might choke off oxygen to the heart or brain.

Aspirin also inhibits cyclooxygenase-2 (COX2), a related enzyme that helps regulate pain and inflammation, such as that caused by arthritis. However, aspirin is a much more effective blood thinner than anti-inflammatory-it typically requires eight times as much of the drug to relieve pain and swelling as it does to reduce heart attack and stroke risk.

My advice: Enteric-coated aspirin should not be used to protect against heart attack or stroke. It has not been well studied for this purpose. The coating may allow aspirin to pass undigested through the stomach, possibly limiting its clot-inhibiting powers.

Who Should Take Aspirin?

The potential for gastrointestinal bleeding problems and other side effects means that aspirin should be used only by people who need it.

My advice: If you have a 10% or greater risk of having a heart attack within 10 years, consult your doctor about aspirin therapy. To learn your heart attack risk, ask your doctor or go to the Web site of the American Heart Association (

If you're a man over age 40 or a woman over age 50 with atherosclerosis (fatty buildup in the arteries)...high cholesterol (total of 200 mg/dL or higher)...diabetes...or a first-degree relative (parent or sibling) with heart disease, you are among those who may benefit from aspirin therapy. Do not begin aspirin therapy without consulting your doctor. A previous heart attack or stroke also means you should discuss aspirin therapy with your doctor.

Heart Attack Protection

Aspirin can be a lifesaver if taken during—and for up to 30 days following—a heart attack, reducing your risk of dying by up to 23%.

My advice: If you think you are having a heart attack, first call 911, then chew 325 mg of aspirin immediately to help prevent the worsening of blood clots.

Caution: Aspirin should be avoided by people who are allergic to it and by those who have a bleeding disorder or asthma that is exacerbated by aspirin.

Important: Chewing 325 mg of aspirin (or four baby aspirin) before swallowing it can cut the absorption time from 60 minutes for an aspirin swallowed whole to 15 to 20 minutes. Never use enteric-coated aspirin for heart attack symptoms—the coating prevents rapid absorption in the stomach.

Caution: Do not take aspirin if you think you are having a stroke. Testing is necessary to determine whether a suspected stroke is caused by a blood clot or bleeding, which could be worsened by aspirin.

Aspirin Resistance

Not everyone who takes aspirin experiences a reduction in heart attack and stroke risk. What's more, none of the dozen or so "aspirin-resistance" blood tests that measure a person's platelet response to aspirin is particularly reliable, according to research done to date.

My advice: Skip the aspirin-resistance tests, and ask your doctor about taking 81 mg of aspirin daily if you are at increased risk for heart attack or stroke.

Ibuprofen And Aspirin

A study by University of Pennsylvania researchers showed that ibuprofen (Advil, etc.) can block aspirin's blood clot-fighting activity—especially if the ibuprofen is taken before the aspirin and/or multiple times daily. Short-term use of ibuprofen (for a couple of days or less) is unlikely to interfere significantly with aspirin.

My advice: If you're relying on aspirin to prevent a heart attack or stroke, avoid long-term ibuprofen use. If you have arthritis or another chronic, painful condition, talk to your doc tor about taking supplements of glucosamine (promotes cartilage formation) and chondroitin sulfate (promotes cartilage elasticity)...using acetaminophen (Tylenol) at the dosage prescribed by your doctor or receiving steroid injections.

Aspirin’s Other Benefits

Research suggests that aspirin may also...

  • Prevent adult-onset asthma. Among 22,000 men enrolled in the Physicians' Health Study, those who took 325 mg of aspirin daily for nearly five years were 22% less likely to develop asthma than those who took a placebo.
  • Reduce the risk for enlarged prostate by up to 50%, possibly by fighting urinary tract inflammation, according to a recent Mayo Clinic study.
  • Curb cancer risks. Of 22,507 postmenopausal women participating in the lowa Women's Health Study, those who took aspirin once weekly were 16% less likely to develop cancer over a 12-year period than non-aspirin users. Other studies suggest that regular aspirin use may reduce the risks for skin, prostate, pancreatic and breast malignancies.
  • Improve longevity. Aspirin may be a good preventive medicine overall. Cleveland Clinic researchers who tracked 6,174 adults for three years found that those taking aspirin daily were 33% less likely to die during that period, with the greatest benefits realized by people who are age 60 or older, unfit and/or diagnosed with pre-existing coronary artery disease.

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