Help yourself -- eat a little dirt

March 01, 2013|By CHRIS COPLEY |

Americans live in a food paradise. Food is generally plentiful, cheap and made to be convenient.

And, despite the occasional food-poisoning event, the food supply is consistently safe to eat. Government food-safety regulations limit amounts of pesticides, microbial pathogens and other contaminants on produce and in manufactured products. Inspectors check on food producers, food manufacturers restaurants and others in the food chain.

But researchers are examining whether Americans' food-safety vigilance has a downside. Is our food too clean?

Go with your gut

Good nutrition is more than eating a balanced diet with plenty of vitamins, minerals, protein and healthful fats. Good nutrition is not just what you put in your mouth, according to Tammy Thornton, registered dietitian with Washington County Health Department. It's also about what happens in your body.

Specifically in your gut.

"The gut is this hollow tube which stretches from (our mouth and) the tip of our tongue to our rectum," she said. "When you look at all the things that happen in our gut, it should be looked at as its own organ. There's more going on in our gut than in many organs in our body."

Good gut health depends on several factors, Thornton said. But recently, researchers have issued surprising reports on the importance of bacteria to proper gut functioning.

"Living in our gut are trillions of bacteria and other microorganisms that are essential for our life," she said. "They influence our digestion, they influence how we use food for energy. Good, healthy bacteria help ward off unhealthy bacteria, which causes illness and harm in our body."

Microbes are bacteria, viruses, fungi and other one-celled creatures that colonize virtually every ecosystem on Earth. Certain species of microbes live in water, in air, on snow, in rock, in boiling-hot vents on the bottom of the ocean.

And microbes live in the human gut. Researchers call the human community of microbes the microbiome. It's a symbiotic relationship. We help each other. Humans give microbes a places to live and plenty of food, and microbes help humans by breaking down food into usable molecules.

But microbes also train the human immune system to fight pathogens.

It starts at birth

Some microbes are beneficial to humans, such as those that produce Earth's oxygen or break sugar molecules into fuel for the body.

Other microbes are dangerous to humans, and we have evolved defenses. When humans become infected with a pathogen, our immune system develops a cell that specifically targets that pathogen.

But we aren't born with a fully functioning immune system, according to Lita Proctor, program director of the Human Microbiome Project at the National Institutes of Health in Washington, D.C.

In a 2011 presentation at The National Academies in Washington, D.C., Proctor said humans inherit their genetic makeup — the hardware, so to speak, of the immune system — but must program the immune system by exposing it to microbes in the environment.

An infant is a microbe magnet, Proctor said. And the first exposure to bacteria comes from Mom.

"Infants acquire their initial microbes from their mother during normal vaginal birth," Proctor said. "Also, from mother's mouth and skin. It comes from the skin of anybody who is handling the child."

Exposure to pathogens, even mild infections such as the common cold, strengthens an immune system, Thornton said. Her family doctor urged her not to be overprotective with her children.

"My kids were diagnosed with allergies to dogs," she said. "The doc said, 'Truthfully, if you rid your son from contact with any allergen, he won't build up any immunities to it.'"

It sounds like a contradiction, but research supports the idea that for long-term healthy, our bodies must be exposed to germs and become infected.

The Hygiene Hypothesis

Dr. Elaine Ashby is a pharmacist and microbiology instructor at Hagerstown Community College. She has watched recent research into the role on human health of a person's microbiome.

She said there is a new proposal gaining traction among researchers: Americans' health is deteriorating because we're too clean. We avoid dirt too much.

"The Hygiene Hypothesis is a hypothesis that lack of exposure to pathogens increases the susceptibility to autoimmune disease," Ashby said.

Ashby emphasized that the Hygiene Hypothesis is not a proven fact, but it's an interesting area of study with some eye-opening results. In studies, people with gut-related health issues do report relief with exposure to bacteria and certain parasites generally considered unhealthy.

"They're tried introducing helminths (intestinal worms) to some people who have autoimmune disease, and they've found that it can reduce the number of attacks, or the problems they have with Crohn's disease or ulcerative colitis," she said. "So there is some evidence that some exposure may help reduce some disease."

Ashby, mother of two grown children, said the idea of living in a bacteria-free environment is virtually impossible. Microbes are everywhere, and most are not dangerous to humans at all.

"I cleaned my office before you came over, but even so, I know that there's plenty of bacteria here, even in a perfectly clean office," she said. "The idea of being exposed to bacteria — babies chew on everything. They're used to putting things in their mouth. We expose our body to all sorts of things."

The human body is a complex organism, Ashby said. And the Hygiene Hypothesis is just that: a proposal that might explain a health problem.

But this is a fact: Exposure to bacteria and disease germs makes immune system stronger.

So, to be healthy, is getting a little dirty better than strict sanitation?

"There is no simple answer," Ashby said. "We'll always be (asking), 'How much can I expose my kids to? Is it good to be clean or should I expose them to some dirt?' But if you never want to get sick again, you're better off getting sick in the first place."

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