The Risks and Benefits of Taking Low-Dose Aspirin

Salicylic acid, the active ingredient in aspirin, has been used for thousands of years as an anti-inflammatory painkiller in the form of willow tree bark extract, which Hippocrates used to “treat fever and to alleviate pain during childbirth.” It became trademarked as a drug named Aspirin™ in 1899 and, to this day, “remains the most commonly used drug in the world.” One reason for its on-going popularity, despite the availability of better painkillers now, is that aspirin also acts as a blood thinner. Millions of people take aspirin on a daily basis to treat or prevent heart disease, which I explore in my video, Should We All Take Aspirin to Prevent Heart Disease?.

It all started in 1953 with the publication of the landmark study “Length of life and cause of death in rheumatoid arthritis” in the New England Journal of Medicine. The paper began with the sentence: “It has often been said that the way to live a long life is to acquire rheumatism.” The researchers found fewer deaths than expected from accidents, which could be explained by the fact that people with rheumatoid arthritis likely aren’t skiing or engaging in other potentially risky activity, but they also found significantly fewer deaths from heart attacks. Why would this be? Perhaps all the aspirin the subjects were taking for their joints was thinning their blood and preventing clots from forming in their coronary arteries in their heart. To find out, in the 1960s, there were calls to study whether aspirin would help those at risk for blood clots, and we got our wish in the 1970s: studies suggesting regular aspirin intake protects against heart attacks.

Today, the official recommendation is that low-dose aspirin is recommended for all patients with heart disease, but, in the general population (that is, for those without a known history of heart disease or stroke) daily aspirin is only recommended “when the potential cardiovascular [heart] disease benefit outweigh the risk of gastrointestinal bleeding.”

The bleeding complications associated with aspirin use may be considered an underestimated hazard in clinical medical practice. For those who have already had a heart attack, the risk-benefit analysis is clear. If we took 10,000 patients, daily low-dose aspirin use would be expected to prevent approximately 250 “major vascular events,” such as heart attacks, strokes, or, the most major event of all, death. However, that same aspirin “would be expected to cause approximately 40 major extracranial bleeding events,” meaning bleeding so severe you have to be hospitalized. Thus, the net benefit of aspirin for secondary prevention—for example, preventing your second heart attack—“would substantially exceed the bleeding hazard. For every 6 major vascular events prevented, approximately 1 major bleeding event would occur; therefore, the value of aspirin for secondary prevention is not disputed.”

If we instead took 10,000 patients who hadn’t ever had a heart attack or stroke and tried to use aspirin to prevent clots in the first place, that is, for so-called primary prevention, daily low-dose aspirin would only “be expected to prevent 7 major vascular events and cause 1 hemorrhagic stroke [bleeding within the brain] and 3 major extracranial bleeding events.” So, the benefits are approximately only 2 to 1, which is a little too close for comfort. This is why the new European guidelines do not recommend aspirin for the general population, especially given the additional risk of aspirin causing smaller bleeds within the brain as well.

If only there were a safe, simple solution free of side effects…and there is! Drs. Ornish and Esselstyn proved that even advanced, crippling heart disease could not only be prevented and treated, but also reversed, with a plant-based diet centered around grains, beans, vegetables, and fruits, with nuts and seeds treated as condiments, and without oils, dairy, or meat (including poultry and fish).

Long-time director of the longest-running epidemiological study in the world, the famous Framingham Heart Study, “Dr. William Castelli was asked what he would do to reverse the CAD [coronary artery disease] epidemic if he were omnipotent. His answer: ‘Have the public eat the diet of the rural Chinese as described by Dr. T. Colin Campbell…’” In other words, as he , “‘If Americans adopted a vegetarian diet, the whole thing would disappear,’ Castelli says of the heart disease epidemic.”

Dr. Esselstyn clarified that we’re not just talking about vegetarianism. “This new paradigm” of heart disease reversal means “exclusively plant-based nutrition.”


Did you know preventing heart disease and stroke aren’t the only benefits of an aspirin a day? A daily aspirin may also decrease the risk of certain cancers. In that case, should we take an aspirin a day after all? See Should We All Take Aspirin to Prevent Cancer? and Plants with Aspirin Aspirations.

For more on preventing, arresting, and reversing heart disease, see:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Cancer-Causing Caramel Color

Caramel coloring may be the most widely consumed food coloring in the world.  Unfortunately, its manufacture can sometimes lead to the formation of a carcinogen called methylimidazole, which was identified as a cancer-causing chemical in 2007. For the purposes of its Proposition 65 labeling law, California set a daily limit at 29 micrograms a day. So, how much cancer might caramel-colored soft drinks be causing? We didn’t know…until now… My video Which has more Caramel Coloring Carcinogens: Coke or Pepsi? explores these questions and more.

Researchers tested 110 soft drink samples off store shelves in California and around the New York metropolitan area, including Connecticut and New Jersey. None of the carcinogen was found in Sprite, which is what you’d expect since Sprite isn’t caramel-colored brown. Among sodas that are, the highest levels were found in a Goya brand soda, while the lowest levels were in Coke products, which were about 20 times less than Pepsi products. Interestingly, California Pepsi was significantly less carcinogenic than New York Pepsi. “This supports the notion that [labeling laws like] Proposition 65…can incentivize manufacturers to reduce foodborne chemical risks…” To protect consumers around the rest of the country, federal regulations could be a valuable approach to reducing excess cancer risk—but how much cancer are we talking about?

Johns Hopkins researchers calculated the cancer burden, an estimate of the number of lifetime excess cancer cases associated with the consumption of the various beverages. So, at the average U.S. soda intake, with the average levels of carcinogens found, Pepsi may be causing thousands of cancer cases, especially non-California Pepsi products, which appear to be causing 20 times more cancer than Coke. Of course, there’s no need for any of them to have any these carcinogens at all “as caramel colorings serve only a cosmetic purpose [and] could be omitted from foods and beverages…” But we don’t have to wait for government regulation or corporate social responsibility; we can exercise personal responsibility and just stop drinking soda altogether.

Cutting out soda may reduce our risk of becoming obese and getting diabetes, getting fatty liver disease, suffering hip fractures, developing rheumatoid arthritis, developing chronic kidney disease, and maybe developing gout, as well.

In children, daily soda consumption may increase the odds of asthma five-fold and increase the risk of premature puberty in girls, raising the likelihood they start getting their periods before age 11 by as much as 47 percent.

If we look at the back of people’s eyes, we can measure the caliber of the arteries in their retina, and the narrower they are, the higher the risk of high blood pressure, diabetes, and heart disease. Researchers performed these kinds of measurements on thousands of 12-year-olds and asked them about their soda drinking habits. Their findings? Children who consume soft drinks daily have significantly narrower arteries. “The message to patients can no longer remain the simplistic mantra ‘eat less, exercise more.’” It matters what you eat. “[S]pecific dietary advice should be to significantly reduce the consumption of processed food and added sugar and to eat more whole foods.”


Prop 65 is lambasted by vested interests, but, as I mentioned, it may push manufacturers to make their products less carcinogenic. Other Prop 65 videos include:

For more background on caramel coloring, see my video Is Caramel Color Carcinogenic?.

There are other soda additives that are potentially toxic, too. See my three-part series on phosphates:

Other coloring agents are less than healthy. For more on this, see Artificial Food Colors and ADHD and Seeing Red No. 3: Coloring to Dye For.

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

The Best Diet for Rheumatoid Arthritis

Rheumatoid arthritis is a chronic systemic autoimmune disease affecting millions. It is characterized by persistent pain, stiffness, and progressive joint destruction leading to crippling deformities, particularly in the hands and feet. What can we do to prevent and treat it?

In my video Why Do Plant-Based Diets Help Rheumatoid Arthritis?, I show a famous 13-month randomized controlled trial of plant-based diets for rheumatoid arthritis where patients were put on a vegan diet for three and a half months and then switched to an egg-free lactovegetarian diet for the remainder of the study. Compared to the control group (who didn’t change their diet at all), the plant-based group experienced significant improvements starting within weeks. Their morning stiffness improved within the first month, cutting the number of hours they suffered from joint stiffness in half. Their pain level dropped from 5 out of 10 down to less than 3 out of 10. Disability levels dropped, and subjects reported feeling better; they had greater grip strength, fewer tender joints, less tenderness per joint, and less swelling. They also had a drop in inflammatory markers in their blood, such as sedimentation rate, C-reactive protein, and white blood cell count. As a bonus, they lost about 13 pounds and kept most of that weight off throughout the year.

What does diet have to do with joint disease?

Rheumatoid arthritis is an autoimmune disease, in which our own body attacks the lining of our joints. There’s also a different autoimmune disease called rheumatic fever, in which our body attacks our heart. Why would it do that? It appears to be a matter of friendly fire.

Rheumatic fever is caused by strep throat, which is itself caused by a bacterium that has a protein that looks an awful lot like a protein in our heart. When our immune system attacks the strep bacteria, it also attacks our heart valves, triggering an autoimmune attack by “molecular mimicry.” The protein on the strep bacteria is mimicking a protein in our heart; so, our body gets confused and attacks both. That’s why it’s critical to treat strep throat early to prevent our heart from getting caught in the crossfire.

Researchers figured that rheumatoid arthritis might be triggered by an infection as well. A clue to where to start looking was the fact that women seem to get it three times more frequently than men. What type of infection do women get more than men? Urinary tract infections (UTIs). So, researchers started testing the urine of rheumatoid arthritis sufferers and, lo and behold, found a bacterium called Proteus mirabilis. Not enough to cause symptoms of a UTI, but enough to trigger an immune response. And indeed, there’s a molecule in the bacterium that looks an awful lot like one of the molecules in our joints.

The theory is that anti-Proteus antibodies against the bacterial molecule may inadvertently damage our own joint tissues, leading eventually to joint destruction. Therefore, interventions to remove this bacterium from the bodies of patients, with consequent reduction of antibodies against the organism, should lead to a decrease in inflammation.

As we saw in my video Avoiding Chicken to Avoid Bladder Infections, urinary tract infections originate from the fecal flora. The bacteria crawl up from the rectum into the bladder. How might we change the bugs in our colons? By changing our diet.

Some of the first studies published more than 20 years ago to fundamentally shift people’s gut flora were done using raw vegan diets, figuring that’s about as fundamental a shift from the standard Western diet as possible. Indeed, within days researchers could significantly change subjects’ gut flora. When researchers put rheumatoid arthritis sufferers on that kind of diet, they experienced relief, and the greatest improvements were linked to greatest changes in gut flora. The diet was considered so intolerable, though, that half the patients couldn’t take it and dropped out, perhaps because they were trying to feed people things like “buckwheat-beetroot cutlets” buttered with a spread made out of almonds and fermented cucumber juice.

Thankfully, regular vegetarian and vegan diets work too, changing the intestinal flora and improving rheumatoid arthritis. However, we didn’t specifically have confirmation that plant-based diets brought down anti-Proteus antibodies until 2014. Subjects that responded to the plant-based diet showed a significant drop in anti-Proteus mirabilis antibodies compared to the control group. Maybe it just dropped immune responses across the board? No, antibody levels against other bugs remained the same; so, the assumption is that the plant-based diet reduced urinary or gut levels of the bacteria.

A shift from an omnivorous to a vegetarian diet has a profound influence on the composition of urine as well. For example, those eating plant-based had higher levels of lignans in their urine. Up until now, it was thought that they only protected people from getting cancer, but we now know lignans can also have antimicrobial properties. Perhaps, they help clear Proteus mirabilis from the system. Either way, these data suggest a new type of therapy for the management of rheumatoid arthritis: anti-Proteus measures including plant-based diets.


I have to admit I had never even heard of Proteus mirabilis. That’s why I love doing work—I learn as much as you do!

I explored another unconventional theory as to why plant-based diets are so successful in treating inflammatory arthritis in Potassium and Autoimmune Disease.

There’s another foodborne bacteria implicated in human disease, the EXPEC in chicken leading to urinary tract infections—another game-changer: Avoiding Chicken To Avoid Bladder Infections.

I have a bunch of videos on gut flora—the microbiome. They include: 

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: Sally Plank / Flickr. This image has been modified.