Should you be taking daily aspirin?
- Published: 12 June 2010
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Tens of millions of people taking a daily aspirin to prevent heart attacks and strokes, often with doctor’s advice to do so. But they are making a serious mistake, writes Dr John McDougall.
I recommend that people who have not already suffered heart disease (a heart attack or heart surgery) or an ischemic brain event (TIA or stroke) not take aspirin for prevention.
This type of therapy is called primary prevention. Meaning, prevention before any vascular events have occurred. There is much controversy surrounding this topic. However, I would not be telling you my medical view unless I believed it was correct.
One of the chief effects of aspirin is to “thin the blood” by inhibiting the activities of blood-clotting elements called platelets. With inhibition, a blood clot (thrombus) is less likely to form suddenly within an artery, causing a heart attack or stroke.
Along with beneficial effects come adverse effects. “Blood-thinning” increases the risk of hemorrhage. Low-dose aspirin therapy substantially increases the likelihood of gastrointestinal (primarily stomach) bleeding and bleeding within the brain tissues.
In the daily routine practice of medicine, the benefits of aspirin for a reduction in risk of heart attacks, primarily in men, and strokes in women, must be weighed against an increase in the risk of major bleeding and, in men, an increase in the risk of hemorrhagic stroke.
Weighing the benefits and risks means guessing—and hoping that more good than harm will have been done at the end of the day.
Don’t use aspirin for primary prevention of cardiovascular disease
The April 21, 2010 issue of the British Medical Journal carried an article with just that title: “Don’t use aspirin for primary prevention of cardiovascular disease.”
The authors explained, “Published evidence does not support the assumption that the benefits clearly outweigh the harms. So the routine practice of starting patients on such treatment for primary prevention of cardiovascular disease should be abandoned… this conclusion holds regardless of such individuals’ gender, blood pressure, or predicted risk of cardiovascular disease, or of whether they have a history of diabetes.”
A recent thorough review of the scientific literature looking specifically at people with diabetes, who are known to have an increased risk of heart attacks and strokes, found. “A clear benefit of aspirin in the primary prevention of major cardiovascular events in people with diabetes remains unproved.”
For secondary prevention, benefits from aspirin outweigh harms
For the person who has already had heart disease (a heart attack or heart surgery) or an ischemic brain event (TIA or stroke), aspirin use is justified.
This kind of therapy is called secondary prevention. The reason aspirin works here is because once a patient has had such a serious vascular event the risk of another one is much higher; thus benefits from treatment will be more easily seen than in a low-risk population.
Note that the risks from taking daily aspirin are also greater in people who have had such a prior event, because those falling into the category for secondary prevention are usually older and sicker.
Overall, among these high-risk patients the use of daily aspirin reduces risk of any serious vascular event by about one quarter; non-fatal myocardial infarction is reduced by one-third, non-fatal stroke by one quarter, and vascular mortality by one sixth.
Low dose is much better than high dose
The full preventative effects of aspirin are accomplished at a very low dosage, because essentially all of the platelets in the body are permanently deactivated with 30 mg of aspirin. New platelets with activity begin to appear in the blood after about four days following taking a single dose of aspirin.
A low dosage of 30 mg has a more favorable effect on platelet activity and fewer side effects (stomach pains and bleeding) than a higher dosage of 300 mg of aspirin.
As the dosage of aspirin is increased from 30 mg up to 1000 mg the side effects increase from 5% to 25% of patients, with no additional benefits for prevention of secondary events, including no reduced risks of dying and/or heart attacks.
Higher dosages, such as 1000 mg (3 adult aspirins daily), may even cause more heart attacks (reinfarctions). In one study, the total reinfarction rate was 22.5 % higher for people taking 1000 mg in comparison to the 30 mg group.
The non-fatal reinfarction rate was 50% lower in the 30 mg group compared with the 1000 mg group.11 The reason for this escalated risk is dosages higher than 30 mg inhibit hormone activities that protect the heart.
Thus, the ideal dosage may be one-third of what is commonly prescribed to patients, a baby aspirin, containing 81 mg of aspirin, daily.
How to stop aspirin safely
There appears to be a rebound from reversing the “blood thinning” effects of aspirin when it is stopped suddenly. Over three times the expected risk of stroke occurs in patients with a previous history of heart disease when they suddenly stop taking aspirin. A similar increase in risk of heart attack has been reported when aspirin was stopped.
No one has determined a safe regime for discontinuing this therapy. I suggest that people needing to stop long-term use of aspirin should do so slowly.
Since as little as 30 mg (1/3 of a baby aspirin) will deactivate all of the body’s platelets, slow withdrawal should begin at about this level. Cut a baby aspirin into quarters (now 20 mg). Take 20 mg then wait for 4 days to take the next 20 mg dose.
Increase the interval between 20 mg doses by one day until a 10-day interval between doses is reached, and then stop taking the aspirin. This is not an easy task since the tablets are so small.
Reduction or discontinuation should be done after obtaining a doctor’s advice on the risks and benefits for each individual patient. Even before reducing the aspirin, patients should change to the McDougall Diet in order to most effectively reduce their risk of strokes and heart attacks.
Don’t overlook the best tool for primary and secondary prevention
The most effective, safest, and inexpensive way to “thin” the blood and prevent blood clots that cause heart attacks and strokes is to avoid the most powerful blood-clotting substances people contact daily, which are animal (saturated) fat and hydrogenated “trans” fats.
By avoiding meat, poultry, eggs, dairy products, and processed foods people naturally and safely thin their blood and prevent tragedies with no side effects, no extra costs, and no rebound effects.
Plus this no-cholesterol, low-fat diet is the same one that heals the underlying artery disease, atherosclerosis, and improves overall health and longevity.
John A. McDougall, MD, is the founder and medical director of the nationally renowned McDougall Program, a ten-day, residential program located at a luxury resort in Santa Rosa, CA. Dr McDougall has cared for thousands of patients over almost three decades of medical practice and has run a highly successful live-in program for more than 20 years.
Dr McDougall is the author of several national bestsellers including: The McDougall Plan: 12 Days to Dynamic Health, McDougall's Medicine: A Challenging Second Opinion, The McDougall Program for Maximum Weight Loss, The New McDougall Cookbook, The McDougall Program for Women, and his latest ground breaking book, The McDougall Program for a Healthy Heart.
A graduate of Michigan State University's College of Human Medicine, he performed his internship at Queen's Medical Center in Honolulu, Hawaii, and his medical residency at the University of Hawaii. He is certified as an internist by the Board of Internal Medicine and the National Board of Medical Examiners.
To make it easier for people to eat well on the go, Dr McDougall co-founded Dr. McDougall's Right Foods Inc., a producer of high quality vegetarian cuisine. The convenience meals are consistent with his health-supporting guidelines of 10% or less calories from fat, strictly vegetarian so there's no cholesterol, and no added oils.
Visit Dr McDougall’s website for details of how to order his books and DVDs.