It is hard to know if the rash of headlines about allergy epidemics is real or hype. Over the past few weeks, anyone reading a variety of quality newspapers would have found themselves thoroughly perplexed.
Last week our news pages quoted a study from the National Research Centre for Environmental Health in Munich saying that children lessen their risk of being sensitive to allergens if they grow up with a dog. Professor Joachim Heinrich and colleagues found that children raised with a dog had fewer allergy markers, such as antibodies to pollen, house-dust mites, cat and dog dander and mould spores. He told the European Respiratory Journal that a dog's presence in early childhood encourages the immune system to develop less sensitivity to allergies such as asthma, eczema and hay fever.
But earlier reports from researchers at Portsmouth University claimed that the incidence of food hypersensitivity - which embraces allergy and intolerance - has not changed in the past 20 years. And they added that parents were too quick to put their children's gripes down to food allergies; people are worrying unduly.
On the letters page of The Times, however, a group of allergists and scientists claimed that we are “in the midst of an allergy epidemic, with about 20 million children and adult allergy sufferers in the UK”.
So what is the truth? There is an idea called the “Hygiene Theory”, or “Hygiene Hypothesis”, which considers whether modern life has become too clean; that in our increasingly sanitised, antibacterial and deodorised age, children's immune systems are not exposed to enough germs to develop normally. According to the market research firm Mintel, Britons spent £612 million on bathing products in 2005; in 2011, the estimated figure will be £709 million.
We have certainly declared war on germs, but has it come at a price? The incidence of certain illnesses - asthma, eczema and respiratory allergy and autoimmune diseases such as arthritis and multiple sclerosis - has soared. Britain now tops the asthma league in Europe. Scientists are still searching for a reason. One clue is that these illnesses afflict only the developed world; they are rare or non-existent in poorer, dirtier countries (where, admittedly, more harmful diseases such as cholera and typhoid are prevalent).
Source - Times