What’s the best way to clean a baby’s dummy? Give it a lick!

OUR instinct is to keep babies clean, to scold them if they pick up something dirty and shield them from other sick children — but could this be increasing their risk of cancer? a new study — the result of analysis of 30 years of data — suggests that a lack of exposure to bugs as a baby could be to blame for the rise in cases of acute lymphoblastic leukaemia (aLL), the most common form of childhood leukaemia.

The study’s author, Professor Mel Greaves, of the Institute of Cancer Research in London, said that an infection could trigger the cancer — but only in genetically-prone children who had a lack of microbial contact within the first year of their life.

In other words, the cancer seemed to strike mainly those who had a ‘clean’ infancy.

Having siblings or going to playgroups, thereby gaining more exposure to a host of microbes, seemed to be protective.

Work is now ongoing to develop a bacteria pill that could be given to children to protect them from cancer and a host of other conditions, from asthma to diabetes, that have been linked to a lack of exposure to bugs.

Which begs the question, are we keeping our children too clean?

The idea that being overly clean might be bad news emerged in the 1980s with the hygiene hypothesis — the suggestion that excess cleanliness underworks our immune system so that it overreacts to harmless substances such as pollen. It was argued that this was why rates of allergyrelated conditions have risen.

Now it is thought that it’s not hygiene that is making us ill but modern lifestyles, including our failure to spend time outside.

The argument is that we evolved to live alongside bugs commonly found in the air, water and on animals, and a lack of exposure to these ‘ old friends’ is causing inflammation and, ultimately, an increase in autoimmune disorders such as type 1 diabetes.

‘The immune system of vertebrates is like a computer, and when you’re born it has hardware and software but no data, so it can’t function until the data is put in it,’ says Professor Graham Rook, a medical microbiologist at University College London, who developed the ‘old friends’ theory.

‘The data comes from microbiota [microorganisms including fungi, bacteria and viruses] that you encounter. Typically this will be from your mum during vaginal delivery, then from your environment. These microbiota, he says, ‘are as much of an organ as your kidneys or liver’ — and without an adequate diversity of them, we become ill.

Being born by Caesarean, not being breastfed, being the firstborn (so no siblings about), antibiotics and a lack of fibre (a source of food for beneficial gut bacteria) all reduce contact with ‘ old friends’, adds Professor Rook.

‘But we’re not saying people need to be less hygienic,’ he stresses. ‘Years ago, people were dying through lack of good hygiene.’

Sally Bloomfield, a hygiene expert and honorary professor at the London School of Hygiene and Tropical Medicine, explains it’s targeted hygiene that is crucial. ‘So we need to worry not about whether something is dirty, but rather whether it is a risk that could make us ill.’

However, some elements of cleanliness are unnecessary for good health for most people, she says.

BLeaCHING sinks and drains is one. ‘ Most people do it to control odours, but when it comes to protecting against infection, if the microbes are down the plug-hole, they’re not likely to be a risk,’ says Professor Bloomfield.

People concentrate on cleaning toilets when they should be paying attention to areas that really matter, such as chopping boards, says Dr Lisa ackerley, deputy chairman of the International Scientific Forum On Home Hygiene. The trend towards antibacterial cleaning agents is also largely unnecessary, says Professor Mark Fielder, a medical microbiologist at Kingston University.

‘ We don’t have to have everything clinically clean the whole time,’ he says. ‘Soap and water is probably better.’

Professor Rook even advocates parents licking their baby’s dummy clean when it has fallen on the floor, rather than sterilising it. He says this may help with transmission of beneficial microbes, citing a study that has shown it can reduce the risk of children developing eczema.

The study found that children whose parents licked their dummies clean were less likely to have eczema at 18 months of age than those whose dummies were washed or sterilised.

One very simple way to improve our exposure to immune-boosting bugs is to get outside more.

‘about a third of the organisms in your gut produce spores that can persist in the environment for thousands of years,’ says Professor Rook. Therefore, where humans have been, ‘the environment is seeded with strains’. So if we go out, we can breathe in beneficial microbes dropped by our forefathers.

Yet there are times when we must all be scrupulously hygienic. During the preparation of food, for example, and everyone should wash their hands when coming in from outside, before eating and after touching pets.

‘People think that the message about hand-washing gets taken too far, but a few years ago a child died in this country after picking up the bacterial infection e. coli from something they picked up at the beach,’ says Professor Bloomfield.