Dear Autumn,

Stomachaches happen for lots of reasons, but they can often be traced back to tiny invaders in the human body: germs.

That’s what I learned from my friends Lisa Woodard and Brenda Bray, pharmacy researchers at Washington State University. Germs like viruses and bacteria are so small you’d need a microscope to see them. Still, they can cause big trouble.

drU-in-worksThere are about 320,000 different types of viruses that affect mammals. Some scientists have estimated there are nearly 10 million more viruses on Earth than there are stars in the known universe. Some viruses will hijack the living cells in humans, animals, and plants to help the virus population grow. That can make the host sick.

Bacteria, on the other hand, don’t need a host, and they too are everywhere. There are about ten times as many bacterial cells in and on our bodies as there are human cells. Some of these bacteria cause stomachaches.

But wait. Not all bacteria are so bad. Certain bacteria that live in the stomach make so many copies of themselves they don’t leave much room for bad germs to grow. Other bacteria help digest your food.

However, every once in a while, when you feel a stomachache coming on, it’s likely certain trouble-making germs have found their way into your system. They can travel on our hands from one human to another or fly through the air, particularly when we sneeze and cough. Our friends at MythBusters found that sneezes can send snot up to 17 feet at a top speed of almost 40 mph.

The best way to protect yourself from germs is to wash your hands after using the bathroom, playing with pets, and before eating, Bray and Woodard explained. And sneeze or cough into a tissue or the inside of your elbow.

“Stomachaches aren’t much fun,” Woodard adds. “But like many physical symptoms our body experiences, they are often a response that our bodies make to help and protect us.”

When germs infect the stomach or intestines, they can cause inflammation and irritation. We call it the stomach flu. Things can get quite gassy, queasy, and gross pretty fast.

The body knows it needs to get rid of the invaders. I bet you could think of one or two ways the germs make an exit.

Sometimes stomachaches happen because we’ve eaten contaminated food or water. Other times the ache starts in the brain when we are stressed or nervous.

Some people might get bellyaches from allergies or because they are sensitive to certain foods. Milk, for example. Some humans can’t break down sugars in milk, so it makes their stomach hurt.

We cats sometimes have the same problem, even though we have a reputation for enjoying milk. Thankfully for humans, scientists have created medication that can help people digest dairy products without the stomachache.

So next time you wake up with an ache in your gut, you’ll know that it’s probably some tiny, troublemaking germs doing their jobs. In the meantime, thank the good germs and health care experts who work hard to help you get better and stay well.

Dr. Universe