Ask Dr. K: Germs on, in us affect our health

DEAR DOCTOR K: Do the germs that live on or in us affect our healths?

DEAR READER: Trillions of germs live in and on us, all of our lives. They live on our skin, in our mouth, in our digestive tract and elsewhere. Recent discoveries have greatly expanded our understanding of these germs and the effect they may have on our health.

Only a few years ago we thought that most of the germs that live on or in us were not affecting our health in any way. We thought they were just along for the ride.

In the past few years, though, new technologies for identifying the germs that live on or in us, and for determining their genes, have produced astonishing results. (A gene is a stretch of DNA that makes a particular protein. Proteins are the workhorses that cause each cell in the body to function correctly.)

We’ve always assumed that it was our genes – the genes inside each of our cells – that define how we function in health and that produce many of our diseases. Many scientists have assumed that once we understood all of our genes and how they worked, we would understand human health and disease.

We humans have more than 20,000 different genes. Recently, we’ve learned that the bacteria that live on and in us have 5 to 8 million genes. Do the math: The microbes on and in us have nearly 400 times more genes than we do! The genes of all those bacteria and other microbes are collectively called the “microbiome.” Genes of the microbiome make proteins that enter our bodies and affect our body chemistry.

Research is also incriminating our gut bacteria in a remarkable spectrum of different diseases. These include obesity, Type 2 diabetes, inflammatory bowel disease, colon cancer, heart disease, psoriasis, non-alcoholic fatty liver disease, asthma and even autism.

This field of research is still in its infancy. We don’t know yet how much effect our microbiome has on our health. But a growing number of scientists think it could be profound.