Germs bite the dust

Don't dismiss dirt, say health researchers, because it helps us stay healthy.

At construction sites across the country, small children tumble about while their young parents, the labourers, can keep an eye on them. The toddlers seem to be happy playing outdoors, at an age when middle-class parents keep their offspring safely indoors and away from dirt and danger.

But dirt is not always dangerous. Studies in the last decade indicate that dirt may be good for us. In 2000, a study on Italian air force cadets showed that those who were, as children, exposed to dirt through their mouths were less likely to have respiratory allergies as adults.

In the developed world, allergies and autoimmune disorders (multiple sclerosis, type I diabetes, celiac disease and others) are on the rise. It’s no coincidence, say researchers, that since the 19th century health authorities have concentrated on making the human environment and food as clean and germ-free as possible. Many lives have been saved, but there has also been a cost. That cost has been borne by our immune systems, which don’t get the exposure that trains them to respond effectively and proportionately. Sometimes they overreact, or turn on healthy tissue.

The key, say researchers, is dirt encountered through the mouth. Small children’s instinct to taste everything may confer an evolutionary advantage. Worms, for instance, enter the body this way. You may shudder, but worms and humans long ago evolved to live with each other. Most worms cause no harm, and some actually help the immune system in ways that are still not well understood. And, mysteriously, a 2007 study in the UK found that dirt can also make us happier — because of a soil bacterium which boosts levels of the “happy” chemical serotonin.

But we can’t discard generations of clean thinking and toss our children into the dirt. So some researchers are thinking about vaccines or other measures that help train the immune system like dirt does.

Mumbaikar Lucano Alvares and his Mexican wife Isa chose to not over-protect their son Orson, now two years old. “A lot of his first year was spent on a farm on the outskirts of Pune,” says Alvares. “It was an organic farm, with rice and cattle. Orson was crawling all over the place.” Now, Alvares says proudly, “He has admirable immunity.

He hardly ever falls sick. Colds and fevers never last more than two-three days. It’s clear to see that he’s much healthier than others his age.” Even allowing for parental exaggeration, that bodes well for Orson’s future.