We have known for decades that donating blood can offer protection against heart disease. A 1998 study of almost 3000 middle-aged men in Finland reported that blood donors had an 88% reduced risk of heart attack when compared with non-donors. Since that landmark study, recent research has revealed even more cardiovascular benefits of donating blood. Blood donors, for example, have been found to have lower total cholesterol and lower LDL-cholesterol than non-donors. In addition, a randomized, controlled trial found that patients who have metabolic syndrome (sometimes called pre-diabetes) can lower their blood pressure, improve blood sugar control, and reduce markers of cardiovascular risk by donating blood.
There are a few simple mechanisms that likely explain why donating blood reduces a person’s risk of heart attack. Most importantly, donating blood reduces blood viscosity—it reduces how thick and sticky the blood is. Hyperviscosity (thick and sticky blood) is a strong predictor of atherosclerosis and cardiovascular disease. Hyperviscosity not only drives the formation of plaques on arterial walls but also increases the chances that one of those plaques will rupture, releasing a clot that can cause a heart attack or stroke. In addition to reducing blood viscosity, donating blood also decreases the body’s iron stores, which can help to decrease oxidative stress and inflammation in the arteries.
Some people will benefit more from donating blood than others. Men and postmenopausal women will likely benefit more than menstruating women, who naturally lose blood on a monthly basis. Patients with metabolic syndrome or diabetes are also excellent candidates for donating blood because they are at particular risk for hyperviscosity and cardiovascular disease.
There are many ways to decrease your risk of heart disease. A healthy diet, exercise, and dietary supplements, such as fish oils, magnesium, and vitamin D, can all help. But if you qualify to donate blood, making it a habit can be an easy and altruistic way to further decrease your cardiovascular risk. The American Red Cross says they need as many as 41,000 blood donations every day to meet the demand for blood; every 2 seconds, another patient needs blood in the United States. Check the American Red Cross web site to find a convenient location to donate. You can start making a difference for those in need while decreasing your own cardiovascular risk.
References  Salonen JT, Tuomainen TP, Salonen R, Lakka TA, Nyyssönen K. Donation of blood is associated with reduced risk of myocardial infarction. The Kuopio Ischaemic Heart Disease Risk Factor Study. Am J Epidemiol. 1998;148(5):445-451.  Uche E, Adediran A, Damulak O, Adeyemo T, Akinbami A, Akanmu A. Lipid profile of regular blood donors. J Blood Med. 2013;439-42.  Houschyar KS, Lüdtke R, Dobos GJ, et al. Effects of phlebotomy-induced reduction of body iron stores on metabolic syndrome: results from a randomized clinical trial. BMC Med. 2012;1054.  Sloop G, Holsworth RE, Weidman JJ, St Cyr JA. The role of chronic hyperviscosity in vascular disease. Ther Adv Cardiovasc Dis. 2015;9(1):19-25.  Holsworth RE, Cho YI, Weidman JJ, Sloop GD, St Cyr JA. Cardiovascular benefits of phlebotomy: relationship to changes in hemorheological variables. Perfusion. 2014;29(2):102-116.  American Red Cross web site. http://www.redcrossblood.org/learn-about-blood/blood-facts-and-statistics.
About the Author: Dr. Gerard Guillory, MD is Board Certified in Internal Medicine and has published two books on Irritable Bowel Syndrome (IBS). In 1985, he opened The Care Group, PC. Today, his clinic is a Primary Care facility that is a hybrid of functional and traditional medicine treating patients with digestive disorders, autoimmune disease, and other conditions. You can learn more about Dr. Guillory here.