Kate Halim
In reality, there are more than 300 blood types, but they all fall into one of four key groups — type A, B, AB or O, collectively known as ABO.
Your parents each pass down their blood type genes and the mix determines your type. So, a type O mum and a type B dad could have a type O or B child, whereas a type O mum and dad could only have a type O child.
Your blood group is determined by genes that you inherit from your parents. It depends on substances in your blood: antigens are proteins found on the surface of red blood cells that cause antibodies to be produced.
According to Dr. Alex Nwobi, what makes the four types different from each other is a molecule known as an antigen that attaches to the outside of your red blood cells.
“If you imagine a red cell as a doughnut, think of these molecules as the sprinkles and trimmings on the doughnut. These antigens are also the reason why blood type might play a role in your health.”
Nwobi noted that they are not all shaped the same way, they contain different sugars and they can alter how the blood behaves and t his is what impacts your risk of disease.
According to researchers from the University Medical Center Groningen in the Netherlands, people with types A, B or AB are 9 per cent more likely to have heart attacks than those with type O.
One reason for this, according to Dr Ellen Maxwell from Melbourne Pathology, could be the way the antigens influence a substance called von Willebrand factor, which causes blood to clot.
“Levels of this are 20-30 per cent lower in people with type O, meaning their blood is simply less sticky compared to non-O individuals,” Maxwell explains.
‘Sticky’ blood is also thought to be why risk of stroke is higher in A, B or AB types — and why men with these types are also more likely to experience erectile dysfunction because the thicker blood may not reach the genitals as effectively as thinner blood.
The antigens might also have an impact on the diseases you’re most at risk of, or how severe they are if you get them. Malaria, for example, is less harmful for people with type O blood.
“The malaria parasite makes a kind of glue that sticks to the type A antigen, causing cells to clump and leading to severe illness. Type O blood doesn’t form these clumps, so infected people don’t get so ill, explains Dr. Nwobi.”
Malaria isn’t the only infection that’s been linked to your blood type. Recent research at the University of Wollongong School of Biological Sciences found that streptococcal infection which can lead to everything from a mild sore throat to a serious blood infection is more likely to attach to type O blood cells.
“The sugars found on O cells are put together in a different way to those found on A and B cells, and we think this makes it easier for the bacteria to hold onto the cells,” says the report.”
Dr. Nwobi advises that if you are a type AB, you might want to keep a particularly close eye on your blood pressure and cholesterol, which are known risk factors for heart disease. Of course, in order to do any of this, you first need to know what your blood type is.
The ABO system
Under this system, your blood may belong to one of four groups:
A – you have A antigens on your red blood cells and anti-B antibodies which are antibodies that attack B antigens.
B – You have B antigens and anti-A antibodies.
AB – You have A and B antigens and no anti-A or anti-B antibodies.
O – You have no antigens, but both anti-A and anti-B antibodies.
The Rh system
Nwobi said that red blood cells can also have another antigen called the Rhesus factor (Rh factor).
“Your blood can either be RhD positive which is also called rhesus positive, this means the antigen is present or RhD negative also called rhesus negative which means the antigen is not present.”
Your blood type is determined by your ABO group and your RhD group. For example, if your blood is group O and RhD positive, your blood group is O positive.
The subtle differences
It is these microscopic substances on the surface of your blood cells that interact with your immune system to either elevate or decrease your risks for several common diseases.
What this means is that depending on your blood type—A, B, AB, or O—you could be more likely to get cancer, ulcers, heart disease or even have memory issues.
Type-A
In general, people with type-A blood are 20 % more susceptible to stomach cancer especially if they drink and smoke than Types B and O. There is a higher incidence of gastric cancer in blood type A population than in people with other blood types.
Type-B
People in this group tend to be more prone to pancreatic cancer. They are more susceptible to memory issues, as well as dementia and Alzheimer’s disease in later years. They also tend to get more ulcers and infections.
The good news is that people with this blood type typically have a higher metabolism than other blood types. Type-B people can build muscle faster and easier and as such, get better results from exercise.
Type-O
People in this group tend to have a lower risk of heart disease. They are 37% less likely to develop pancreatic cancer. This blood group also has a lower risk of heart attack and stomach cancer than the other groups.
People with this blood type are less likely to develop pancreatic cancer. Type-O men are prone to obesity while women who are type-O tend to have lower fertility levels.
Type-AB
People with the AB blood type are 23% more likely to develop heart disease. They have a greater risk for cognitive issues.
Pregnant women with Type-AB have a higher risk of developing high blood pressure known as preeclampsia.
People with type AB blood are 82% more likely to experience difficulties with memory recall.
Blood Type AB individuals share the benefits and challenges that both Blood Type A and Blood Type B individuals may face.