E. coli, short for Escherichia coli, is a type of bacteria that can mess with your gut or urinary tract. Depending on the strain, it might cause diarrhea or that awful burning feeling when you pee. While some E. coli strains are actually helpful for digestion, others, especially the kind lurking in contaminated food, drinks, or surfaces that might have a touch of poop, can cause infections.
Certain groups of people–like infants, older adults, or those with conditions like diabetes or weakened immune systems–are more likely to get sick from E. coli. Interestingly, your blood type might also play a role in how sick you get.
This doesn’t mean that people with a certain blood type are bad at washing their hands or hang out in places littered with poop. But if you catch a specific strain of E. coli, people with the A blood type are more likely to end up with diarrhea, according to a 2018 study in the Journal of Clinical Investigation. Why? This strain produces a protein that’s extra clingy to cells in people with blood type A. It sticks to the gut lining, making it easier for the bacteria to cause more severe symptoms.
What makes blood types different?
Blood might look the same to the naked eye, but on a cellular level, it’s actually quite different depending on your blood type. Your red blood cells have specific proteins called antigens on their surface. If you’re blood type A or B, your red blood cells have the A or B antigen. People with AB blood have both A and B antigens, but no antibodies in their plasma. On the flip side, people with O blood type don’t have A or B antigens on their red blood cells, but they do have both A and B antibodies in their plasma. The “+” or “-” in your blood type refers to the Rhesus (Rh) factor.
These antigens and antibodies aren’t just about blood compatibility—they also affect how your immune system responds to bacteria. A 2015 review in Clinical Microbiology Reviews explains that specific antibodies can recognize and destroy certain bacteria. However, some blood types are more vulnerable to particular bacterial strains. For example, Enterotoxigenic E. coli (a strain of E. coli that causes diarrhea) produces toxins and proteins that help it stick to cells in your gut. These toxins are more likely to bind to people with A or AB blood types.
Other ways your blood type can affect your health
Your blood type doesn’t just affect your risk of infection. Certain blood types are also linked to specific conditions like heart disease. While factors such as cholesterol, blood pressure, and smoking status play a role, the ABO gene can also increase your risk. The ABO gene is present in people with A, B, or AB blood types. According to Penn Medicine, people with these blood types who live in highly polluted areas are at a greater risk for heart disease compared to those with the O blood type.
Although people with A blood type have a higher risk of developing diarrhea from Enterotoxigenic E. coli, a 2021 review in Biochemistry Research International also found that type A blood is linked to smallpox and infections from Pseudomonas aeruginosa. Those with B blood type might be at a higher risk for gonorrhea, tuberculosis, strep, and salmonella. Infections like salmonella, smallpox, and E. coli are also more common in people with AB blood type. Meanwhile, type O blood, the most common blood type, is associated with an increased risk of mumps, tuberculosis, and cholera.