It takes all types; YOUR HEALTH.
FOR centuries, scientists believed blood types only mattered over transfusions.
Now research suggests your blood group could make you more prone to certain illnesses - and also protect you.
Different groups are determined by antigens, which are immune defence systems on the surface of red blood cells. Each one evolved to protect us against lethal diseases specific to a time and place, which is why different ethnic groups have a different ratio of blood types.
Here's how your blood group could affect your health
Blood type AB may increase your risk of cognitive problems, according to research from the journal Neurology. Specifically, older ABs were more likely to have difficulty learning or recalling lists of items.
Professor Mary Cushman, of the University of Vermont, says: "We know blood type AB is related to levels of certain clotting factors and to proteins in the blood. While this may help explain why type ABs are more likely to develop thinking problems later in life, the exact mechanisms aren't clear."
More bad news if you're blood type AB - your risk for gastric cancer is roughly 26% higher than if you had B or O. And if you're type A, your risk is 20% higher than type B or O.
According to a study by Gustaf Edgren, of Karolinska University Hospital in Sweden, a common bacteria in our gut called H. pylori may be to blame.
Those with blood type AB or A may have a heightened reaction to it that increases their cancer risk.
If you're type O, you may have an increased risk of ulcers - thanks again to H. pylori bacteria.
"This blood group somehow modifies the body's immunological response to the bacteria, but we don't know exactly how," says Gustaf.
Thank your lucky genes, type Os. Your blood may lower your risk for heart disease by up to 23%.
A Harvard School of Public Health study also shows that people with blood types AB and B were at the greatest risk. Certain groups have been linked to higher rates of inflammation, which could partly explain their connection to heart disease.
More good news for type Os: you're 37% less likely to develop pancreatic cancer, suggests the Journal of the National Cancer Institute. Once again, researchers point to the presence of the gut bacteria H. pylori for the higher disease rates among non-O blood types.
Stomach bugs and weight gain
Research shows Os are more vulnerable to norovirus, the potentially lethal vomiting and diarrhoea bug.
Also, men with type O might be more prone to piling on the pounds, say Danish researchers. They have found that type O men who are exposed routinely to pollution at work have a raised risk of obesity compared with other men.
A study by Copenhagen's Bispebjerg University Hospital says that the pollution sets off chronic inflammatory responses that can result in type O men becoming overweight.
Your blood group can affect the chances of conception. A US study of more than 560 women in fertility treatment found that those with type O were up to twice as likely to have a lower egg count and poorer egg quality. Group A women seemed better protected against their egg counts falling over time.
There are also fears that AB blood may treble the risk of suffering preeclampsia during pregnancy.
WHAT ARE THE MOST COMMON BLOOD GROUPS?
There are eight different blood groups:
O-positive: 38% of the population
O-negative: 7% of the population
A-positive: 34% of the population
A-negative: 6% of the population
B-positive: 9% of the population
B-negative: 2% of the population
AB-positive: 3% of the population
AB-negative: 1% of the population
Your particular blood group is dependent on your genes inherited from your parents. Around 86% of the UK population are rhesus positive and the most common blood group is O.
WHY IS BLOOD GROUP IMPORTANT?
Most of us usually find out our blood group if we need a blood transfusion.
This is because we can only accept certain blood groups and getting this wrong can be fatal.
For example, giving group B blood to someone with group O would have a massive rejection reaction. But there's good news for those with blood group AB positive, known as the 'universal recipient' type, because they can accept blood from any group. Those who are O negative can donate to any blood group, so it is known as the 'universal donor' type.
Blood group is especially important when pregnant, mainly because if you are a negative blood group you will need injections when pregnant to make sure that you don't reject the baby, who might have a rhesus positive blood group.
This is the main cause of mother/baby rejection which can be life threatening for the unborn child. However, this can also happen when mother and baby have the different blood groups A and O. This will be monitored throughout your pregnancy and treated as needed.
HOW CAN YOU FIND OUT YOUR BLOOD GROUP?
GPs won't routinely test your blood type for you as they say there's little medical benefit in knowing without a real cause for on Around concern. But if you are ever in need of a blood transfusion, doctors will determine your blood group before you're given a drop of blood.