Can you be too clean?

Those of us who were born in the grubbier days of no washing machines or showers have a secret conviction that we were healthier (if we didn’t die of diptheria or polio) than today’s more sanitary tots. In the ‘90s there was quite a swell of opinion that our immune systems were so unchallenged that they didn’t know how to rise to any emergency. With some reason, it’s pointed out that countless products such as toothpaste, soap, laundry detergents and even clothes now routinely include antibiotics in their manufacture. Not only does this build resistance to a quick antibiotic shot when we really need it, but it lulls our immune systems into torpor.

Scientists are beginning to treat that idea with new respect. They recognise now that the bacteria in our gut, collectively called our microbiome, is a very complex system in its own right. Each person’s microbiome is so individual that it is in close touch with his or her inique combination of inner and outer environments. A recent scientific paper said, ‘gut microbiota may even be considered as another vital human organ.’ That’s why antibiotics commonly cause diarrhoea – introducing such foreign ‘soldiers’ into a peaceable gut community causes warfare and deaths. No wonder long courses of treatment (including ‘chemo’ for cancer) leave you feeling so peelie-wallie. The really interesting thing, though, is that microbiomes are also affected by their outside environment, including things like house dust and the aerosol effect of flushing a toilet. Partial microbiome transplants have been found to work wonderfully well for people whose own internal system has been knocked out of kilter.

The most amazing thing, though, is that our gut bacteria can affect the way our brains work, and influence the way we think and feel. Transplanting gut microbiota from relaxed and adventurous mice into the guts of timid and anxious ones at once reduces their stress and makes them happier and more adventurous. Don’t all rush, now, but this could see Relate in the waste paper basket.

Some of the conditions that could be linked to the state of your gut bacteria include asthma (often linked with gastritis, surprise, surprise?) obesity, mood disorders, acne and a whole range of childhood disorders and ‘food fads’. James Greenblatt, a psychiatrist and clinical faculty member at Tufts Medical School, successfully treated a teenager with obsessive-compulsive disorder (OCD) by boosting her ‘good’ bacteria with high-powered probiotics. There’s a lot of interest in investigating the state of the gut bacteria in autistic children.

Meanwhile, it might be an idea to go out in the garden and get your hands dirty.