20 Amazing Facts About Your Blood Type

Memorizing your blood type is critical for all sorts of reasons, from knowing who you can accept blood transfusions from to who you can donate your blood to. Not to mention the role it plays in your likelihood of contracting COVID-19. And now, as doctors and scientists do increasingly more research on how a person's blood type can affect their health, there's even more of an incentive to pay attention to whether you're A, B, AB, or O—and whether you're positive or negative, too.

For example, recent studies have found that a person's blood type can mean anything from an increased risk of depression to a higher likelihood of developing diabetes. Curious about what your own blood type means? Keep reading to find out. And for more incredible information about your body, check out 23 Facts About Your Brain That Will Blow Your Mind.

Although people with type O blood are more susceptible to bites, they can thank their genetics for one thing: protection against malaria. Oddly enough, scientists have found that folks with type O blood seldom die from malaria, seeing as the RIFIN protein—the protein that causes malaria—is less able to bond to type O blood cells and therefore cannot do as much damage.

If you have type O blood, then your heart is in luck: According to research presented at the 2017 World Congress on Acute Heart Failure, individuals with this blood type are less likely to suffer a heart attack or stroke. The bad news? Individuals who are type A, type B, or type AB—in other words, some 63 percent of the overall population—have a 9 percent increased risk of both coronary and cardiovascular events. And for more things you can do prevent a serious medical condition, check out 30 Crucial Ways to Lower Your Heart Attack Risk.

Stomach cancer and type A blood seem to go hand in hand. That's according to a 2015 study published in the journal Cancer Epidemiology, which found that people with type A blood were 38 percent more likely to develop stomach cancer than those with type O blood. And for more things you should know about your abdomen, check out This Is Everything Your Stomach Is Trying to Tell You About Your Health.

Though non-A blood types are relatively less likely to get stomach cancer, they still have to worry about pancreatic cancer. In the same 2015 study, researchers found that all non-O blood types were at a higher risk of pancreatic cancer, and subjects with type B blood were 59 percent more likely to come down with the cancer. And for more on the symptoms of this particular condition, check out 13 Warning Signs Your Pancreas Is Trying to Tell You Something's Wrong.

If your blood type is AB, then you'll want to keep a close watch on your cognitive health. One 2014 study published in the journal Neurology analyzed the relationship between blood type and brain health and found that people with type AB blood had an 82 percent higher risk of cognitive impairment. And for more on protecting yourself from cognitive issues down the road, check out 40 Habits to Reduce Your Risk of Dementia After 40.ae0fcc31ae342fd3a1346ebb1f342fcb

The minority of the population who is Rh negative is at a higher risk of certain mental health issues. A 2015 study of more than 3,000 subjects published in the journal PLoS One found that "Rh negative men more often reported certain mental health disorders including panic disorders, antisocial personality disorders, and attention deficits."

In addition to mental health issues, people with Rh-negative blood types are also more prone to developing allergies. In the same PLoS One study, researchers found that subjects with Rh-negative blood were slightly more likely to have skin allergies. And for more helpful information delivered straight to your inbox, sign up for our daily newsletter.

Whether or not you're Rh positive or Rh negative could have an impact on your pregnancy. According to the American College of Obstetricians and Gynecologists, problems can occur when a woman is Rh negative and her fetus is Rh positive, as this can result in something called Rh incompatibility.

"If the blood of an Rh-positive fetus gets into the bloodstream of an Rh-negative woman, her body will understand it is not her blood and will fight it by making anti-Rh antibodies," the organization explains. "These antibodies can cross the placenta and try to destroy the fetus's blood. This reaction can lead to serious health problems and even death in a fetus or newborn."

While type O is the most common blood type overall, it's especially prevalent in the Latino-American community. According to the American Red Cross, approximately 53 percent of Latino-Americans are type O+ and 4 percent are type O-.

That statistic about the Latino-American community makes sense, seeing as negative blood types—whether type A, type B, type AB, or type O—are few and far between. In fact, according to the Oklahoma Blood Institute, only about 18 percent of the total U.S. population has a negative blood type.

Wondering who pioneered this science in the first place? In 1909, Austrian scientist Karl Landsteiner became the first person to properly identify the four main blood groups. It's thanks to his research that we now know which blood types to use (and which not to use) with patients in need of transfusions. In 1930, he was rewarded for his contributions when he was given the Nobel Prize for Physiology or Medicine.

One of the many things that can contribute to a woman's fertility is her blood type. At the Yale University Fertility Center in 2011, researchers analyzed subjects' levels of follicle-stimulating hormone (FSH) and found that women with type O blood were more likely to have higher FSH levels. The problem is that high levels of FSH are typically an indication of a diminished ovarian reserve, which means that a woman with type O blood might be less likely to get pregnant as she gets older.

Have you ever wondered what makes your blood type A, B, AB, or O? Turns out, it's all about the sugar.

The blood types are named after antigens that are found on the surface of your red blood cells. These antigens are simple chains of sugars, according to Stanford School of Medicine. "The A flavor makes the A sugar, and the B one makes the B sugar. It turns out that the O flavor doesn't make any sugar," according to Stanford. "Someone that's 'AO' will be type A, because the O flavor of the gene makes no sugar. This person only has the A sugar."

But what about the positive or negative element? Well, that's all about the Rhesus factor (or Rh factor). If you don't have the Rh factor, your blood is negative. If you do have it, your blood is positive.

Type O- blood is in extremely high demand at hospitals—not just because it's one of the rarest blood types, but also because it's the "universal donor." Because O- is Rh-negative, it can be given to people with both positive blood types and negative blood types. These folks can also donate to A, B, and AB blood types. Though a foreign antigen could cause the body to attack, there are no antigens present in type O blood, so there's nothing to attack.

If your blood type is AB+, then you're in luck. This blood type is known as the "universal recipient," seeing as people who have it running through their veins can receive blood from any type A, type B, type O, or type AB donor. Because type AB blood contains both A and B antigens, as well as the Rh factor, it can tolerate a transfusion from anyone on the ABO spectrum.

Though doctors and scientists aren't entirely sure what causes cancer, one thing that they do know is that people with type B blood are more likely to develop certain cancers. In fact, one 2012 study published in the World Journal of Gastroenterology found that type B blood individuals were about 50 percent more likely to be diagnosed with both esophageal and biliary cancers.

Type A, type B, and type AB blood types have been shown to have higher levels of the proteins von Willebrand factor and factor VIII, both of which contribute to clotting. In fact, a 2007 study published in the Journal of Thrombosis and Haemostasis found that people with type A, B, or AB blood were 31 percent more likely to develop venous thromboembolism, a condition in which a blood clot forms in the leg, groin, or arm and lodges itself in the lungs.

When French researchers analyzed data from some 82,000 women in 2015, they found that those with type A blood were 10 percent more likely to develop type 2 diabetes and those with type B blood were 21 percent more likely to develop the disease. The scientists hypothesize that a person's blood type may play a role in their gut microbe makeup, which could, in turn, affect metabolism and contribute to diabetes risk.

According to 2015 research published in the International Journal of Science, Spirituality, Business and Technology, "people [in Japan] strongly believe that the blood type influences one's personality, weaknesses, and strengths."

Per these beliefs, people with type A blood are calm and collected, artistic, and polite; people with type B blood are practical, goal-oriented, and strong-willed; people with type O blood are outgoing, energetic, and outspoken; and people with type AB blood tend to have characteristics on both sides of the spectrum.

Many factors contribute to whether or not you are a magnet for mosquitos, including your blood type. In one 2004 study published in the Journal of Medical Entomology, researchers found that one species of mosquito—Aedes albopictus—landed on 83 percent of subjects with type O blood and just 47 percent of subjects with type A blood. Scientists believe that mosquitos may be able to sense the sugars some people secrete through their skin based on their blood type.