From a heart attack to erectile dysfunction – how your blood type can affect your health
IT'S handed down from our parents and we all have one - but how does your blood type affect your health?
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.
We each come under one of these groups and, while type O is the most common in the UK, your blood group is determined by your genetics.
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.
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,” Professor Robert Flower, from the Australian Red Cross Blood Service, said.
These antigens are also the reason why blood type might play a role in your health.
They’re not all shaped the same way, they contain different sugars and they can alter how the blood behaves.
This is what impacts your risk of disease.
Heart attack and erectile dysfunction
According to researchers from the University Medical Center Groningen in the Netherlands, people with types A, B or AB are nine 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 our 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,” Ellen explains.
Sticky blood is also thought to be why risk of stroke is higher in A, B or AB types.
Men with these blood 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.
Strep infection
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,” Robert said.
“Type O blood doesn’t form these clumps, so infected people don’t get so ill.”
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 in Australia found that group A 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,” according to Dr Martina Sanderson-Smith, from the Illawarra Health and Medical Research Institute, who worked on the trial.
Tummy bugs and stomach ulcers
Other conditions that have been associated with blood type include cognitive decline, which is highest in AB, though experts aren’t yet sure why.
Stomach ulcers are higher in those with type O as they’re more prone to contracting the H. pylori bacteria that causes them.
Type Os are also more likely to catch the winter vomiting bug, norovirus.
Infertility
There are also some studies that suggest a link between blood type and fertility.
One study from Italy found that women with type B blood had the best chance of pregnancy, while research at Yale University in the US found that women with type O blood were most likely to have lower egg quality.
Do you need to worry?
The overwhelming answer on whether blood type science is a cause for concern is: proceed with caution.
The studies so far have been small and a correlation doesn’t always mean a direct link between two things.
“Generally, health conditions are multifactorial,” Ellen explained.
“Just one thing doesn’t determine if you’ll be affected.”
However, forewarned is forearmed.
So, for example, if you’re 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.
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