Dirty little secrets

Right from our birth, ‘good’ germs help us survive in a nasty world

— You’re probably going to want to wash your hands after reading this. Cold and flu season has arrived — not as eagerly anticipated as deer season, but still a hunt of sorts, with germs in the cross hairs. To resist the flu, there’s a vaccine. For colds, the arsenal partly lies within our bodies. And evidence is sometimes as plain as the runny nose on a kid’s face. That snotty nose is a sign of a functioning body. That fluid has a job: flushing germs from the nose and sinuses. The impulse to wipe it is good. The impulse to stop it with a dose of antibiotics is not. “The reality is, kids are going to get sick, and most kids are going to do fine,” said Dr. Chad Rodgers, one of seven pediatricians at Little Rock Pediatric Clinic. “They’re going to have to develop their own immunity.” That’s why an antibiotic is neither needed nor useful with colds, which are caused by viruses, not bacteria, he said. If a child doesn’t have a fever and is still eating well, it’s all right to let nature take its course, he said. “The fact that the body is producing mucus means the body is intact and the body is fighting.” While it’s not pretty, mucus is a sign that things are working as they should, he said.

“Bacteria” might sound like a dirty word, because the germy, disease-causing ones get more press. But our bodies are full of hard-working, beneficial bacteria, too. And we’re only just beginning to understand their relationship to us.

The most comprehensive study of this to date is the Human Microbiome Project, a five-year effort involving 200 scientists from 80 institutions and funded by the National Institutes of Health. Findings were released earlier this year.

ECOSYSTEM ENCOUNTERS

The study looks at our bodies as a biome — an ecosystem — of microbes. Each of us carries trillions of bacteria, an estimated 2 to 5 pounds’ worth (which means for some of us, those bacteria collectively outweigh our brains).

Some produce substances we can’t. Many are involved in digestion. Some regulate appetite. Some help us build immunity. And the ranks of those workers are thinned, some of those jobs left unfilled, when antibiotics that rightly target the bad bacteria also wipe out the beneficial ones.

Rodgers cautions that hygiene can be taken to an unhealthy extreme. “There’s some research that we live in too sterile an environment, and that’s why we’re seeing more allergies and the immune system is not producing an immune response,” he said.

It’s an idea that has come to be called the hygiene hypothesis: “We have become too clean,” said Kevin Young, professor of microbiology and immunology at the University of Arkansas for Medical Sciences. And when children’s exposure to bacteria in the environment is reduced, they have become less able to handle exposure later and more prone to allergies and asthma.

Dr. T. Glenn Pait, a UAMS neurosurgeon, has been talking about antibiotics and germ resistance on his radio segments, Here’s to Your Health, broadcast on radio station KUARFM, 89.1.

“When bacteria become resistant to first-line treatments, the risk of complications and death is increased,” he said. “The failure of first-line antibiotics also means that doctors have to resort to less conventional medications, many of which are more costly and associated with serious side effects.”

A GOOD DEFENSE

“Our body has lots of defense mechanisms against germs,” Rodgers said. “We still would encourage good handwashing, but some people go overboard.

“If you’re doing so much bleaching that your hands are turning red, then you’re probably overdoing it.”

At the clinic, and across the country, doctors are documenting an increase not only in environmental allergies, but in food allergies too, he said.

The first few years of life are crucial for making the introductions that will help little bodies build robust immune systems, he said.

In developing a healthy immune system, it’s important for babies to meet and take in these natural microorganisms early on. And early means very early. We meet many germs as we enter the world — in the birth canal. “Our first interactions are probably the transfer of all these organisms,” Young said.

“We acquire these bacteria early on in our life for our immune system to mature,” and that’s why it’s important for children to be introduced to some germs. “It’s kind of like practice,” he said. “Your immune system practices and develops, and this is a really hot area of research, how this develops.”

DINNER AND A SHOW

The microbiome project harvested and studied microbes from numerous body sites of more than 200 healthy Americans. An interactive graphic on the Scientific American website offers a show and tell for what some of the bacteria look like, where they live, and what they do.

(At scientificamerican.com, search for “explore microbiome.”)

In the stomach, Helicobacter pylori can be the cause of some gastric ulcers, but it is now thought to also play a role in regulating appetite.

In the intestines, Bacteroides thetaiotaomicron loves eating carbohydrates, and good thing; otherwise we wouldn’t be able to digest oat bran fiber.

In our mouths, several bacteria work to keep yeast at bay.

And then there’s the bad boy in our guts, Escherichia coli.

Young, the UAMS microbiologist, is a bit of an evangelist for E. coli. “I like to say that I go around preaching the gospel that E. coli is your friend,” he said.

Each of us carry about 100 million copies of E. coli, he said. “That’s a minority of the bacteria that we have.”

Like other germs, E. coli arrives “probably from your mother, during birth,” he said. Babies delivered by Caesarean section probably receive it from hospital personnel.

One of E. coli’s jobs is making several vitamins, including vitamin K, “which we cannot make ourselves,” he said. Vitamin K, which is also found in leafy green vegetables, helps in blood coagulation.

Of the thousands of bacteria in our guts, only three perform another necessary job — producing a chemical called indole. Of the three, E. coli is the workhorse.

When we eat foods with the amino acid tryptophan, these bacteria turn it into indole, a substance that literally holds our guts together.

Imagine the epithelial cells lining your intestines. They come together in a junction, and there are gaps between the cells, where stuff can leak through. “The more indole you have, the tighter these junctions become,” he said, like a tightly woven cloth, keeping everything where it belongs.

Indole also helps to make mucus, which also helps to protect cells inside us, he explained. And research has shown that indole also has antifungal properties, “so it reduces the likelihood of your getting fungal infections.”

THE GOOD FIGHT

Taking antibiotics is necessary to fight some infections, but it fights the good germs too — like making them take a sick day from their jobs because their numbers are depleted.

To the question of whether we are overmedicating ourselves with unnecessary antibiotics, “The vast majority of microbiologists you would ask would say yes,” Young said, “mainly because we don’t know what we’re doing in many cases, and we’re just now learning that.”

“We don’t know what we’re doing to our normal flora,” he said. “It’s possible we’re creating the situation for organisms to become more resistant to those antibiotics.”

The same theory applies to overuse of topical antibiotic products. Pediatrician Rodgers advises resisting the antibacterial advertisements that seem to proliferate like campaign ads. Most, he said, “are just trying to get people to buy products that they don’t really need.”

Experiments have shown that, in terms of removing bacteria from the skin, there’s no difference between using plain soap and water and using antibacterial products, Young said.

So the products may be unnecessary, and there’s one way they’re “potentially bad,” he said.

The theory that exposure to germs is good for humans is supported by studies comparing people who grew up on farms and those who grew up in cities. The farm folk were less likely to have asthma and autoimmune diseases, he said. “Our immune system needs a little exercise, evidently.”

This sounds like good news for parents who aren’t fanatical about housekeeping.

“Maybe,” Young said. “It’s like Goldilocks. You don’t want to be too dirty or too clean; you want to be just right.”

Family, Pages 34 on 11/28/2012

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