Parents can HALVE their baby's risk of asthma if they avoid exposing them to house dust, nuts, eggs and dairy products
Findings contradict the 'hygiene hypothesis' that exposure to allergens and germs boosts immunity 11% of children protected from allergens such as nuts and dairy products developed asthmaCompared to 27% of those exposed to the allergens

Emma Innes


16:56 GMT, 21 March 2013



16:56 GMT, 21 March 2013

Protecting babies from highly allergenic foods and dust mites in their first year of life can prevent the development of asthma during childhood, a new study has discovered.

Researchers found that a child's risk of developing the condition is reduced by more than half if their contact with common triggers of allergy

The new research contradicts the so
called ‘hygiene hypothesis’ – the theory that being exposed to allergens
at a young age reduces a child’s risk of developing asthma and

Professor Hasan Arshad, a consultant in allergy at Southampton General Hospital, conducted the 23-year study.

Protecting babies from highly allergenic foods and dust mites can actually prevent the development of asthma during childhood

Protecting babies from highly allergenic foods and dust mites can actually prevent the development of asthma during childhood

He said: ‘Although genetic links are
arguably the most significant risk factor for asthma in children,
environmental factors are the other critical component.

‘Although this was a small study, we have found that the risk of developing asthma at some point during childhood is reduced by more than 50 per cent if we introduce control of a child's environment.’

Researchers assessed 120 patients with a family history of allergies.

The children were recruited at birth 23 years ago to find out whether or not breastfeeding mothers who avoided dairy products, eggs, soya, fish and nuts, while also using vinyl mattress covers and pesticides to kill dust mites, had a lower risk of seeing their children develop asthma.

They performed follow-up tests when the children were two, three, four, eight and 18 and found that while only 11 per cent of those in the prevention group had developed asthma by age 18, more than a quarter of those who were naturally exposed to substances linked to allergic reactions had the condition.

Mr Arshad said: ‘By introducing a combined dietary and environmental avoidance strategy during the first year of life, we believe the onset of asthma can be prevented in the early years and throughout childhood up to the age of 18.

The new research contradicts the so called 'hygiene hypothesis'

The new research contradicts the so called 'hygiene hypothesis'

‘Our finding of a significant reduction in asthma using the dual intervention of dust mite avoidance and diet modification is unique in terms of the comprehensive nature of the regime, the length of follow-up and the size of the effect observed.’

The research, published in the journal Thorax, and funded by the National Institute for Health Research (NIHR), is the first study to show a persistent and significant reduction in asthma throughout childhood.

Mr Arshad, who is also chair of allergy and immunology at the University of Southampton, and is based at the NIHR Southampton Respiratory Biomedical Research Unit, said there was now an urgent need to replicate the findings in a large multi-centre study.

Asthma is an increasingly widespread problem in the UK with one in 11 children currently receiving treatment for the condition.

A recent study by the Harvard Medical School revealed contradictory information to that found by the researchers at Southampton General Hospital – it showed that dirt and germs can protect against disease – and that our indoor-based, ultra-clean lifestyles are bad for our health.

It supported the idea that without exposure to dirt and germs early in life, the immune system does not learn how to control its reaction to everyday invaders such as dust and pollen.

This can lead to it miss-firing later in life, leading to allergies and other illnesses.

The evidence came from researchers who studied germ-free mice, bred in a bubble, kept in sterile cages and fed sterile food.

The lungs and bowels of the germ-free mice contained extra-large numbers of a type of immune cell blamed for asthma and bowel problems.

And when the germ-free mice developed asthma or bowel condition colitis, it was much more severe than usual, the journal Science reported.