Scientists sniffing out the Western allergy epidemic

allergens Allergens are all around us, but only some of us are sensitive to them

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One in three of us is allergic. From grass pollen to latex, peanuts to pets, allergies send 20,000 of people in England to hospital every year.

But generations before did not suffer from this epidemic, so what is it that's making us so allergic in our modern world?

Many theories have come and gone over the years, but now scientists think they may have discovered what's to blame - and BBC Two's Horizon has put this theory to the test.

Every one of us is covered head to toe with bacteria, and intriguingly scientists believe these microscopic bugs are the key to explaining why we are becoming more allergic.

Families under the microscope

The bacteria that cover our skin, line our mouths and fill our guts not only outnumber our own cells by about 10 to one but may play a vital role in training our immune systems. Changes to our lifestyles are influencing these microorganisms, and allergies are the consequence.

To see if this theory played out in the real world, Horizon put the lives of two allergic families under the microscope.

Joe with his family Joe with his mother Caroline, father Danny and sister Freya

In one of the families, eight-year-old Joe suffers from severe asthma, hay fever, eczema, and nut, pet and dust mite allergies.

In the other, four-year-old Morgan's list of allergies is seemingly endless. Along with severe eczema and hay fever, he is allergic to dairy products, nuts, soya, kiwi fruit, avocado, banana, latex, cats, dogs and horses.

Both families gamely agreed to provide bacterial swabs of their skin, guts and even their homes in the hope they might offer clues about why they suffer from allergies.

The most common allergies
  • pollen
  • house dust mites
  • mould
  • wasps and bees
  • pets such as cats and dogs
  • industrial and household chemicals
  • foods such as milk, nuts and eggs

The results were incredible. Like most of us in the Western world, the families had far fewer types of bacteria living in and on them when compared with people in traditional tribes in parts of the developing world. One hunter-gatherer community was found to not only have a higher diversity of bacteria, but only one in 1,500 suffered from an allergy - compared with one in three in the UK.

Life in the West appears to be changing our bacteria and susceptibility to allergy. But what is it about the Western lifestyle that is to blame?

There are likely to be many culprits, but a big factor could be how we are bringing up our children.

Today a quarter of babies in the UK are born by Caesarean section. That is a significant statistic in light of a Norwegian study that found Caesarean babies were 52% more likely to suffer from asthma than those born vaginally.

Threat from antibiotics

Scientists believe the bacteria that babies are exposed to in the birth canal somehow help protect them from allergies, and the rise in Caesarean births may be making children more allergic.

But the assault on their bacteria appears to continue as they grow up. Breast milk is now known to contain up to 900 species of bacteria, possibly explaining why exclusively breast-fed babies are less likely to suffer from allergies.

One of the greatest threats to allergy-protecting bacteria comes from antibiotics. These medicines, meant to protect us, often severely reduce our harmless friendly bacteria.

Researchers at King's College London and Guy's and St Thomas' NHS Foundation Trust, together with the University of Nottingham and Aberdeen Royal Infirmary, found that the use of antibiotics in early life may increase the risk of developing eczema by 40%.

There is no doubt that children today are being exposed to fewer bacteria than they were in the past, and they are suffering more allergies.

But it is not just the way our children are born that impacts their bacteria. How they are brought up also makes a difference.

girl walking the dog

As Horizon tracked the movements of the two families over 24 hours, it discovered that they spent on average 91% of their days indoors - a pattern reflected across the UK. As our lives become increasingly sedentary we miss out on the vast array of bacteria that lurk in our gardens and waft through the air.

So, arguably, the easiest thing for all of us to do to reduce our chances of becoming allergic is to go outside. Whether it is walking the dog or strolling to school, the evidence suggests that being outside and taking a good deep breath of fresh air is good for you.

'Old friends'

One study has even found that if you have more plants and flowers around your house you are not only more likely to have a diverse array of bacteria on your skin, you are also less likely to be allergic.

Professor Graham Rook, of University College London, calls these bacteria our "old friends", and has no doubt of their importance to our health.

He says: "In a way, this realisation that humans are in fact ecosystems and that we depend so much on these microorganisms is probably the most important advance in medicine in the last hundred years."

The discovery that "friendly" bacteria shape our immune systems is revolutionary, and as Horizon explores the latest research in this field it will make you reconsider everything from what you eat to how your body works.

If you want to find out more about what you can do to reduce you or your children's chances of becoming allergic watch Horizon - Allergies: Modern Life and Me, broadcast on BBC Two at 9pm on Wednesday, 27 August.


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  • rate this

    Comment number 457.

    Whilst the friendly bacteria angle sounds very plausible, I also suspect children born with more severe allergies didn't make it past early childhood in the past / in developing countries today. Natural selection comes into play as it's thought some allergies have a genetic component.

    We have no allergies in our household, could it be down to my hatred of cleaning, well it's my excuse!!!

  • rate this

    Comment number 445.

    I have worked in the asthma and allergy area of Pharma for many years and the best environment for a new born baby is to have a little sister or brother who gets dirty by playing outside and a dog. Getting out close to nature is really important. A study undertaken in Finland showed that asthma is almost non existent in its rural population and very high amongst the city population.

  • rate this

    Comment number 436.

    Lets see if we can put todays known allergies into a historic perspective:

    50 years ago some allergies (Hay fever) were known and a few received medication

    100 years ago the term allergy was not used but they were instead probably grouped together with many other illnessess and deceases being treated with no modern drugs or medicines

    200 years ago basic medicine was just starting.

  • rate this

    Comment number 370.

    Our vegetables, salads and fruits are too clean these days due to supermarket demands, yet they go off quickly once at home, even in the fridge in the dark.

    My mother used to boil or roast potatoes in their skins and never washed the greens and just topped and tailed the carrots before cooking.

    We are losing out on essential minerals to by eating hygienically washed vegetables and salads.

  • rate this

    Comment number 336.

    Having lived in a city / urban location for most of my life (now 62) I moved 9 years ago into the middle of the countryside.

    Hopeful for clean fresh air I was shocked to find that my breathing became impaired - on further investigation many locals explained that they suspected agricultural spraying was causing many different ailments.

    Something is very wrong!


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