It’s a beverage that’s been brewed and consumed worldwide for thousands of years. What is this libation, you ask? Beer.

There are hundreds of reasons people drink beer, but new research shows that there may be at least one reason why you shouldn’t quaff it regularly.

A new study from Spain found that people with a particular combination of genes, microbes and pattern of beer consumption have an increased risk for developing gastric cancer. The unseen risk factors are found in people who have two copies of a gene variant that helps break down alcohol in the body. These folks also have a bacterium in their stomachs that is known to cause gastric cancers and ulcers, and a habit of having a few beers every day.

The study shows people who down at least two to three beers a day have a seventy-five percent increased risk of gastric cancer. But those who drink at least two to three beers with the right genetic predisposition and the bacterium living in their gut have a seven-hundred percent increased risk of gastric cancer.

People who drink wine and liquor didn’t show the same elevated gastric cancer risks.

Stomach cancer is the world’s second leading cause of cancer death behind lung cancer. But Americans tend to have lower rates of stomach cancer because many lack the bacterium that is a known cause of the disease.

Researchers say the study illustrates a classic gene-environment interaction. But the unfortunate thing about hidden risk factors is just that … they are indeed hidden.

These genetic culprits and the microbes are not likely to be found during any routine visit to the doctor.

But what people do know is how much beer they consume, and whether they have a family history of stomach cancer.

Those are issues people can discuss with their physicians.