Scientists Highlight the Blood Group Associated With a Greater Likelihood of Stomach Cancer

For decades, researchers have explored whether blood type may influence the risk of certain diseases. One area that continues to attract scientific attention is the possible connection between ABO blood groups and stomach cancer.

Several studies suggest that people with certain blood types — especially blood group A — may have a slightly higher likelihood of developing stomach cancer compared to other groups. However, experts emphasize that blood type alone does not determine whether someone will develop the disease.

Here’s what scientists currently know about the possible link.

What Is Stomach Cancer?

Stomach cancer, also called gastric cancer, develops when abnormal cells grow in the lining of the stomach.

It is one of the most common cancers worldwide, although rates vary greatly between countries.

Symptoms may include:

• Persistent stomach pain
• Bloating
• Loss of appetite
• Nausea
• Unexplained weight loss
• Feeling full quickly
• Indigestion that does not improve

In many cases, symptoms may not appear until the disease becomes more advanced.

Which Blood Group Has Been Linked to Higher Risk?

Research over many years has found that people with blood type A may have a somewhat increased risk of stomach cancer compared to people with blood type O.

Scientists first noticed this possible association decades ago, and later studies continued investigating the connection.

Some researchers believe this may be related to:

• Immune system differences
• Inflammation patterns
• Interactions with bacteria such as Helicobacter pylori (H. pylori)

However, the exact reason is still not fully understood.

The Role of Helicobacter pylori

One major factor in stomach cancer risk is infection with Helicobacter pylori, a bacterium that can damage the stomach lining over time.

H. pylori infection is very common worldwide and is considered one of the strongest known risk factors for gastric cancer.

Some studies suggest that blood group A may influence how the body responds to this bacterium, though more research is needed.

Not everyone infected with H. pylori develops stomach cancer, but long-term infection may increase inflammation and damage inside the stomach.

Blood Type Is Only One Small Factor

Experts stress that blood type alone is not enough to predict cancer risk.

Many other factors play a much larger role, including:

• Smoking
• Heavy alcohol consumption
• Diet high in salty or processed foods
• Family history
• Obesity
• Chronic stomach inflammation
• H. pylori infection

In fact, many people with blood type A never develop stomach cancer, while people with other blood types can still get the disease.

Common Symptoms That Should Not Be Ignored

Doctors recommend seeking medical attention if symptoms persist, especially:

• Ongoing stomach pain
• Frequent indigestion
• Difficulty swallowing
• Vomiting blood
• Black stools
• Sudden weight loss
• Persistent nausea

Early detection may improve treatment outcomes.

Can Stomach Cancer Be Prevented?

While no method guarantees prevention, experts say several lifestyle habits may help reduce risk:

Eat a Balanced Diet

A diet rich in:

• Fruits
• Vegetables
• Whole grains

may help support stomach health.

Reducing heavily processed, smoked, and salty foods may also help.

Avoid Smoking

Smoking significantly increases the risk of many cancers, including stomach cancer.

Limit Excessive Alcohol

Heavy alcohol use may irritate and damage the stomach lining over time.

Treat H. pylori Infection

Doctors can diagnose H. pylori through breath, stool, or blood tests.

If detected, antibiotics are commonly used to treat the infection.

What Scientists Still Don’t Know

Although the link between blood type A and stomach cancer has appeared in multiple studies, researchers continue investigating:

• Why the association exists
• Whether genetics play a larger role
• How bacteria and immunity interact with blood groups

Scientists caution that risk associations do not mean certainty.

Final Thoughts

Research suggests that blood group A may be associated with a slightly greater likelihood of stomach cancer, but blood type is only one piece of a much larger picture.

Lifestyle, infections, genetics, and environmental factors all contribute to overall cancer risk.

Rather than focusing only on blood type, experts recommend paying attention to symptoms, maintaining healthy habits, and seeking medical advice when digestive problems persist.

Sources

• National Cancer Institute
• World Health Organization (WHO) – Cancer
• American Cancer Society – Stomach Cancer
• Mayo Clinic – Stomach Cancer Symptoms and Causes