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2015-11-20 07:21:19
We take long showers, change clothes every day and wash our hands regularly. Is
this doing us more harm than good?
What s your routine? Do you shower every morning, or skip a few days? Do you
change the bedsheets weekly, or only when they get smelly? How about your
towels: New ones like clockwork every Saturday, or do you wait until they
are, well, just that a touch on the manky side?
We live in an age of cleanliness. Our soaps are antibacterial. Our household
cleaners promise to kill 99.9% of germs. Microbes are bad, plain and simple.
But at the same time, some scientists also tell us that being too clean is also
wrong, because it might help cause asthma and allergies. So is there a balance
between keeping obsessively clean and learning to live with the bacteria all
around us?
Not all of our body has to be washed as stringently as our hands (Credit: Getty
Images)
We have known since the late 19th Century and the discoveries of German
physician Robert Koch that certain bacteria cause specific diseases. Since
then, sanitation and cleanliness have dramatically improved our health.
Yet not all microbes are bad. Yes, there are bacteria that cause unpleasant or
even deadly diseases, but lots of them are extremely useful and beneficial to
our health. They make vitamins in our gut, coat our skin to protect us from
harmful microbes, and help us digest food. Outside of our bodies, they
decompose organic waste, make half the world's oxygen and fix nitrogen levels
in the air helping make the Earth the life-supporting planet it is. Today,
many scientists argue that people have become too clean for their own good.
We need contact with the microbial biodiversity from the environment Graham
Rook, University College London
In 1989, the British epidemiologist David Strachan was the first to suggest
that the exposure to infections during childhood would provide a good defence
against allergies in later life. It s an idea known as Hygiene Hypothesis .
An allergy is, in fact, our immune system going haywire, by perceiving a
harmless substance as a major attack. Our bodies, says Dorothy Matthews,
biologist at Russell Sage College in Troy, New York, may overreact to
beneficial microbes, because our immune systems have forgotten how to live with
them.
For this reason, we may have to understand how microbiota the microorganisms
living on and in our body can help us. It is essential to pass on the
maternal microbiota symbiotic harmless organisms in the gut, skin and
elsewhere and we need contact with the microbial biodiversity from the
environment, says Graham Rook, an epidemiologist at University College London.
Weeding out pathogens
Take a baby s dummy that s fallen to the floor. It s better for the mother to
suck it clean rather than provide a new sterile one, he says, because this has
been shown to accelerate development of the infant's microbiota, and reduces
allergies. One could arguably describe it as exposure therapy, starting with
food. Eat a varied diet, preferably with farm produce, says Rook. It s also
better to exercise in nature, not a gym. And while we might think dogs are
dirty, they also help most of us to increase microbial biodiversity and reduce
allergies.
In a way, the immune system is like a farmer. It makes sure that our bodies
have the microbes that are important for our development, physiology,
metabolism, even brain functions, while at the same time doing plenty of
weeding, getting rid of the microbes that contain pathogens. No wonder that a
lack of diversity in our microbiota is associated with a huge range of
illnesses. Having said that, there is still no convincing proof that the lack
of a specific type of microbe can cause a particular disease. This might well
come one day, says Rook, but the problem is technically and statistically
enormously complex.
Some scientists believe our lack of contact with bacteria may be behind a rise
in allergies and asthma (Credit: Getty Images)
Others agree. The microbiome has been linked to immunity, autism, allergy,
autoimmunity, mood, and the development of our central nervous system, says
Mary Ruebush, microbiologist and instructor at Becker Professional Education
School. And this exposure therapy begins the moment we are born children who
are delivered vaginally have much lower rates of allergy than those delivered
via caesarean, possibly because of this early exposure to the mother s normal
vaginal flora, she adds.
Our exposure to good microbes early in life can be an enormous benefit to our
health, explains Rook. For instance, early exposure to microbes in our gut
activates some immune cells in such a way that as we get older, they do not
over-respond to microorganisms. Rook calls these microbes our old friends .
And we are missing their friendship, because extreme cleanliness means that
often we don t come in contact with microbes in the same way that our ancestors
did.
Overall obsessive washing disrupts the normal flora which keep you healthy by
competing with harmful organisms
This presents something of a conundrum for people hoping to live healthier
lives. How can we avoid disease from the bad bacteria, while still fostering
the good bacteria? Rook certainly wouldn t advocate skipping the essentials,
such as washing your hands. Scientists consider dirty hands as one of the most
likely reasons why infections are passed between us. Getting your hands clean
is not just a question of how long you wash them, but how well . You have to
apply soap and water, rub all surfaces of the hands thoroughly for at least 15
seconds, then rinse under running water and then dry them, say the experts. The
rubbing with soap detaches the germs from your skin, while the rinsing takes
them off the hands.
But not all of our body has to be washed so stringently. Overall obsessive
washing disrupts the normal flora which keep you healthy by competing with
harmful organisms , says Ruebush. Operating your immune system in an
environment of sterility is like a sensory deprivation for the brain.
Eventually, it goes insane, thus the increased amount of allergy and
autoimmunity associated with persons who try too hard to avoid all exposure to
anything in their environment, she says. A long shower every day may not be
advisable, as it removes the good bacteria from our skin. But you should wash
around your genitals and anywhere you sweat a lot. And you should change your
underwear every day.
Some of the helpful bacteria on our skin helps protect us from more harmful
bugs (Credit: Science Photo Library)
Around the house, the solution for fighting the wrong kind of bacteria is not
excessive cleaning, but timely cleaning. Good hygiene is not a once-a-week,
deep-down clean, it needs to be an ongoing part of our daily lives, where
hygiene measures are targeted where and when necessary," says Sally Bloomfield,
of the London School of Hygiene and Tropical Medicine, and chair of the
International Scientific Forum on Home Hygiene.
Take chopping boards in the kitchen. If you cut your greens, it s ok to wait
until after dinner to do the washing up. Not so if you ve chopped raw fish or
meat. Instant action is required, or you could put your family at risk of
infection.
After all, it s well established that about 70% of all chicken are contaminated
with Campylobacter, a bacterium which can cause food poisoning and will happily
multiply on your chopping board.
Damp dangers
Hospital studies show bedlinen and towels can easily spread viruses and germs,
but our homes are not quite the high-risk environment that will breed the next
superbug. But fluffy wet towels can be a problem.
There is no scientific data which could allow us to explicitly state how often
we should change bed linen, towels etc, says Bloomfield, but there is enough
data to say that they can be an infection risk in the home. She recommends to
change bedlinen and towels about once a week, and warns strongly against
sharing hand towels and other personal care items.
If you chop meat on a chopping board you should wash it right away (Credit:
Science Photo Library)
Warm damp cloths are a particular haven for nasty bugs, says Bloomfield. That s
why cloths in both the kitchen and bathroom should ideally be discarded and
washed after every use. Failing that, at least rinse them well immediately
after use and dry them, recommends Bloomfield. Tea towels, meanwhile, are
ideal for drying dishes, if you are keen to spread your germs to all the
glasses and plates in your cupboard. Regular, even daily swaps are highly
recommended. And laundry of towels and linen should be done at 60C (140F) to
beat the bugs, or with oxygen-based bleaching agents in the washing powder if
it s done at lower temperatures.
When it comes to bathrooms, it doesn t help, of course, that all-too-few people
close the toilet lid when flushing. If you can t be bothered, remember that an
open lid is a gateway for all the bacteria inside to spread and multiply.
Let your children play in places where they have contact with soil and
vegetation, which are rich in beneficial microbes Ilkka Hanski
Pyjamas are another weak point in many people s personal hygiene. Some surveys
suggest that many make the smell test before putting them in the wash. Change
them at least once a week, say the experts. Ultimately, it s all about getting
on top of the critical [infection] control points, says Bloomfield.
The overall message, then, is not that we should return to living in squalor as
to try to embrace good bacteria; we need to be just as vigilant without our
homes to keep them free from germs. Instead, Ilkka Hanski, a biologist at the
University of Helsinki in Finland, says, it s important to get out of the house
and spend time in woodlands and forests. Let your children play in places
where they have contact with soil and vegetation, which are rich in beneficial
microbes, he says. If you have a house, don t maintain a lawn, let native
plants take over and grow taller. Cut them once or twice a year.
Strength after sickness
Studies show the benefits. Children who grew up in an environment that was not
obsessively clean have lower rates of allergy and asthma. And certain bacteria
also actively protect us from bowel disease and even some types of anxiety and
depression.
A healthier life, it seems, can be boosted by exposure to farm animals and
harmless but vital microorganisms in dirt, food, and water. Microbial exposure
is important for promoting the development of effective regulatory pathways
that keep inflammation under control, says Thom McDade, a biological
anthropologist Northwestern University in Evanston, Illinois.
If the hygiene hypothesis is correct, it may explain the rapid rise of both
asthma and allergy cases during the past 20 years. Of course, there are other
explanations too, for example public health trends such as the widespread use
of purified water, the overuse of antibiotics, and of course changes in our
environment such as higher levels of pollution.
Living with a dog could help give your immune system a boost (Credit: Getty
Images)
It is likely that many factors that are part of the Western lifestyle are
involved. Antibiotics will disturb the beneficial microbes in our bodies and
thereby harm the immune responses, says Hanski. In contrast, he adds, studies
clearly show that vaccines are not harmful and play no role in the increase in
allergies.
On the plus side, says Ruebush, you can take heart in knowing that every time
you get a little sick, you get a little stronger. The message is not one that
most people want to hear: they want the quick pharmaceutical fix for the
slightest bit of discomfort. But every time you take the quick fix, you make
your body a little weaker. That s something to remember the next time you re
tempted to slather on the shower gel.