An Aspirin-a-Day May Cause Anemia

December 2012, updated February 2015

Nearly 40 years ago, studies found that a single daily dose of aspirin could prevent death from heart attacks.  Due to those initial and subsequent studies, physicians have routinely recommended up to 325 milligrams of aspirin daily for people at elevated risk of heart attacks/high blood pressure.   Physicians are now recommending aspirin for a widening variety of medical conditions, including cardio- and cerebrovascular disease, vascular dementia[1], and cancer[2].

However, recent meta-analysis results have found that for individuals at low risk for cardiovascular disease, aspirin reduces heart attack risk while increasing the risk of major bleeding.[3]   That is because aspirin is an acetylsalicylic acid, and salicylates damage gastric walls and prolong bleeding.  

The American Heart Association recommends that individuals who are at risk for gastrointestinal bleeding or hemorrhagic stroke should not follow an aspirin regimen.[4]   People who have the greatest chance of bleeding are those who have ulcers or who have had a stroke caused by bleeding in the brain.[5]  The National Institute of Health reports that 15 million people in the U.S suffer from peptic ulcers and ulcerative colitis[6], and the Canada Digestive Health Foundation reports that Canada has the highest incidence of gastrointestinal ulcers in the world.[7] 

However, not all individuals taking aspirin have readily visible bleeding.  Using capsule endoscopy (a tiny camera inside a capsule), patients with unexplained iron-deficient anemia were evaluated and those taking uncoated low-dose aspirin were found to have significantly higher number of small bowel mucosal breaks than those taking low-dose aspirin plus anticoagulants (drugs that prevent blood from clotting like warfarin or heparin) or the control group who took no drugs.[8]  These mucosal breaks could be causing undetected bleeding, and subsequent anemia (i.e., low hemoglobin).  

In the absence of overt bleeding, the research is not conclusive that low-dose aspirin causes low hemoglobin among all adults, although it does indicate an association between low-dose aspirin and low hemoglobin among the elderly.  Among the elderly, anemia is associated with increased mortality, morbidity, falls and disability, and deterioration of cognitive functions; and iron deficiency is associated with declines in quality of life.[9]

To guard against iron deficiency or anemia, everyone should regularly consume foods rich in iron such as green leafy vegetables, liver, and beans.  If supplements are necessary, take supplements that contain iron chelated (i.e., bound with amino acids) to maximize bioavailability.*  Easy-to-digest supplements are those that contain fiber or cellulose (sometimes referred to as “controlled”, “timed” or “slow”).*  Fiber tablets will disintegrate or dissolve over a longer period which reduce gastrointestinal distress and increase absorption.*   Individuals taking aspirin regularly should beware, consult with their physician and have their hemoglobin levels tested periodically to ensure that they are not suffering from iron deficiency or anemia.  

*These statements have not been evaluated by the Food and Drug Administration.
This product is not intended to diagnose, treat, cure, or prevent any disease.

[1] Alzheimer’s Society, The Journal of Quality Research in Dementia, < >, accessed February 11, 2015

[2] Aspirin, Cancer and Heart Disease,  accessed February 11, 2015

[3] Raju NC and Elkelboom JW, “The aspirin controversy in primary prevention,” Current Opinion in Cardiology, September 2012: 499-507.

[4] American Heart Association, < > (accessed February 11, 2015)

[5] Salynn Boyles, “Aspirin Therapy for Heart Disease, Stroke Prevention Not for Everyone,”  < > (accessed December 14, 2012).

[6] Digestive Disease Statistics for the United States < - 03-14-2012> accessed December 14, 2012 > (accessed December 14, 2012).

[7] Statistics <> (accessed December 19, 2012).

[8] Ehrhard F, Nazeyrollas P, Brixi H, Heurgue-Berlot A, Thiefin G, “Proximal predominance of small bowel injury associated with uncoated low-dose aspirin therapy: a video capsule study in chronic users”, European Journal of Gastroenterology and Hepatology, November 25, 2013.

[9] Gasekell H, Derry S, Moore, RA, “Is there an association between low dose aspirin and anemia (without overt bleeding)?”, BMC Geriatrics September 2010