Amanda Rankin explores the so called 'hygiene hypothesis', the idea that the huge increase in asthma and allergies generally has its origins in our domestic obsession with cleanliness.

Home sweet home. As a mother of two young children, that’s where I spend most of my time, and much of that time is spent cleaning, tidying and washing in an attempt to keep dirt at bay and my home and children in a reasonably clean state. But how sweet is my home really, and how safe is it for my children’s health?:

Recent and not so recent research is revealing that keeping our homes hygienically clean and protecting our children from contact with dirt, disease and animals is responsible for the massive increase of immunological diseases such as asthma. The so-called ‘hygiene hypothesis’ proposes that this lack of exposure to bacteria, domestic animals, childhood diseases and good old dirt in the first years of life adversely affects the developing immune system. According to scientists, exposure to organisms in the natural environment stimulates healthy immune responses and helps develop a non-allergic system. Good hygiene means the immune system has got nothing to work on - so it starts to overreact to harmless substances like pollen, animal dander and dust.

The result can be asthma, and in Australia alone over two million people suffer. Approximately 15 per cent of children are currently diagnosed with asthma, which equates to one in six children under the age of 14. Some studies put the figure at one in four children, but whatever the number, this debilitating, life threatening disease has doubled in the last two decades in urban areas. In fact, asthma is one of the most common reasons for hospital admissions in children and 397 people died due to asthma in Australia in 2002.

Asthma is undisputedly a disease of Western society, but can it blamed squarely on our obsession with hygiene? Could all that hand washing and floor mopping actually be making us sick? That’s exciting news for people who hate cleaning, but unfortunately the cause of asthma is not that simple. According to the medical profession, it is more likely a combination of environmental factors, genetics, lifestyle and diet. It could be said it is a disease of urban living and separation from nature.

Leading asthma physician Professor Christine Jenkins agrees that the 'hygiene hypothesis’ could certainly be contributing to the increase in asthma, but says it is just one of many factors. “While we do think hygiene and allergy are an important aspect, we do think obesity and lack of physical activity also play a role,” she explains. “We think it is very multi-factorial and that there will never be a single unifying hypothesis.”

Jenkins is head of the Asthma Group at the Woolcock Institute of Medical Research in Sydney and her recently published book Know Your Asthma is a handbook for asthma management, aimed at helping individuals and families live with this insidious disease. Asthma, Jenkins says, may turn out to be more than one disease and is particularly difficult to diagnose in children. Recurring respiratory problems and wheezing do not automatically mean a child is asthmatic and scientists are now saying respiratory infections in early life are beneficial to the immune system. “Early life respiratory infections have an important role in stimulating the maturing immune system into healthy Type 1 immune responses and reduce the likelihood of persistent Type 2 allergic responses,” states Jenkins.

She says while the reasons for the increased incidence of asthma may be hard to pinpoint there is much a new mother can do to reduce the chance of her child developing asthma, starting prenatally. Not smoking is the most scientifically proven first step, and that includes avoiding passive smoking while pregnant. Children of smokers are inclined to have smaller lungs, more respiratory problems, viral bronchiolitis and wheezing episodes.

Once her baby is born, the best thing a new mum can do is breastfeed, breastfeed and nothing else for at least six months. Extensive studies on bottle-fed children found that 25 per cent were more likely to be diagnosed with an allergy than children who received only breast milk during the early months. The total duration of exclusive breastfeeding was less important, although longer breastfeeding was associated with fewer allergies and asthma.

“There is a little bit of evidence that children introduced to solid foods under the age of six months may be more likely to get asthma but it is early days in that area,” continues Jenkins. “But breastfeeding for the first six months of life is protective against early respiratory tract infections and wheezing illnesses up to the age of three. After the age of three, there is no persuasive evidence that breastfeeding has a beneficial effect.”

While you might not be comfortable with the idea of throwing your newborn in with the chickens, co-existing with animals does protect a child from developing allergies in the first years of life. Epidemiological studies carried out in Europe showed that children in close contact with cows and pigs were less likely to develop asthma than urban children because the bacterial endotoxins that animals secrete help stimulate normal immune responses. Other research shows that infants who attend daycare under the age of one suffer fewer allergies, as do children with older siblings, all factors that marry well with the ‘hygiene hypothesis’. All those grubby hands, runny noses and sharing of germs might make us parents cringe, but nature apparently knows best.

In urban environments, people spend over 80 per cent of their time indoors and, in contrast, the closest most of us get to chickens is the fast food variety. Research is suggesting that the air inside our homes is increasingly poisonous due to the sheer number of chemicals we come into contact with - not just in cleaning products, but in the synthetic materials used in carpets, wood products, paints and furniture and the use of reverse cycle air conditioning recirculating the indoor air.

Tragically, children are often the first to suffer. With a large proportion of their time spent indoors, coupled with their mother’s possible obsession with keeping them clean, our infants are breathing in an immeasurable cocktail of chemicals in gaseous or particle form. An infant’s metabolic rate is much higher than an adult’s, so they are breathing more rapidly, and their immature immune system is also at risk, increasing the likelihood of the child developing allergic sensitivities.

There are approximately 250 chemicals present in the average urban household and the toxic effects are more than evident. Runny noses, itchy eyes, wheezing and headaches are not just an excuse to stop doing the housework! There is a pile of evidence that chemicals such as formaldehyde, ammonia and chlorine are connected to respiratory problems, allergies and even cancer. The toxicity of cleaning products is nothing new and it is not just the ones used in the home. Shampoos, conditioners, body washes, soaps, moisturisers and cosmetics are all full of these chemicals and very few people seem to want to make much of a fuss about it.

I am one of the luckier mothers who read Dr Peter Dingle’s books Sick Homes: Parts 1 & 2, before I had children and changed my ways quick smart. Not that I was a huge fan of cleaning in the first place! But Dingle’s many years of research into the toxic chemicals that permeate every corner of our homes was all I needed to dump those poisons in the bin. I also found out about locally produced, completely safe products that wouldn’t harm my health or my children.

I now use microfibre technology, occasionally Bicarbonate of Soda, and a few essential oils like Tea Tree and Lavender to provide some nice smells. My washing detergents are all reputable, environmentally sound products, including the ones I use on my family’s skin and hair. Are we a dirty family? I don’t think so, and I rest easy with the knowledge that I am protecting my precious children’s lungs and skin as much as I can, not to mention stopping them from poisoning themselves.

“The research is showing that the more chemicals you have in the home the higher the level of asthma, allergies, allergic reactions and skin complaints,” says Dingle, an environmental and nutritional toxicology expert and a leading researcher in Health and the Environment at Murdoch University in Perth. “We were able to show about eight years ago that healthy kids had respiratory problems in houses with slightly elevated levels of formaldehyde.”

Alas, a stroll down the supermarket aisle is all it takes to reveal that most people still equate cleanliness with chemicals, and don’t expect the government to do anything about it. While a small number of chemicals are regulated, cleaning products are generally open slather. The consumer has no idea what chemicals are contained in the product and the marketing is so seductive that the consumer can’t imagine that it is highly toxic. How could something that is ‘lemon fresh’ or ‘infused with eucalyptus’ be dangerous?

“The commercial stations are full of ads about dishcloths which are anti-bacterial, and everything has got to be antisepticised in some way for us to feel it is okay,” agrees Professor Jenkins, who recommends new mothers should not go overboard with cleanliness and sterilisation. “Now, that’s a load of baloney. Evolutionarily, we have developed to co-exist with micro-organisms.”

“We just have to go back to basics,” is Dingle’s answer to our increasing immunological health problems, “and one of them is moving away from toxic chemicals. There is no doubt about that whatsoever, and that means everywhere.”

Everywhere includes the chemicals in our food and the quality of our diet. According to research, asthma sufferers are likely to be deficient in selenium, zinc, and Vitamins C and E, and certain food colourings (102, 110,127) and preservatives (220-230) have been linked to asthma attacks. There has also been some research into the positive affects of supplementing with Omega-3 fatty acids (EFAs) while pregnant, but it is early days yet as to the impact on the incidence of asthma. EFAs that are found in cold water fish such as tuna, mackerel and salmon have an inflammatory mechanism and supplementation can reduce asthmatic wheezing in those already diagnosed as asthmatic.

“It is clear that we are all deficient in Omega-3s, but what is also very clear is that, historically, we were meant to have Omega-3s in our diet,” says Dingle. Just mention the three words ‘cod liver oil’ to your grandmother and watch them grimace at the memory of the daily dose. Luckily today, we have far less pungent capsules to do the job, but if you have the courage, two teaspoons of cod liver oil a day is recommended for long-term asthma control.

Vaccinations, antibiotics and better sanitation have almost eradicated the nasty diseases children came into contact with two centuries ago. A privileged child in a Western city will not die from the plague, typhoid, cholera, diphtheria, polio or small pox, and this is surely a good thing. But the consequence of being too protective, too hygienic may be immune system imbalances that result in a range of equally debilitating and fatal diseases.

Thirty years ago, the major childhood illnesses were chickenpox, measles and mumps. Today it is asthma, ADD and cancer. This might be the price we pay for progress, but don’t bother waiting around for cosmetics and cleaning products to be banned due to their health dangers. Throw out all those nasty bottles in your home, make a feminist statement and refuse to be part of the poisonous ‘beauty’ industry. Ensure your children eat lots of fruits, vegetables, and whole foods, and give them the most beautiful gift in life, good health.

Know Your Asthma is published by Vital Books and can be purchased directly from the publisher on 1300 303 944 RRP $39.95