Interesting article about our immune systems/allergies

[Guest guest]

(ellen)

excerpts:

" We've developed a cleanlier lifestyle, and our bodies no longer need

to fight germs as much as they did in the past, " said Marc Mc, a

pediatric allergist at the University of Michigan Health System. " As a

result, the immune system has shifted away from fighting infection to

developing more allergic tendencies. "

" The natural immune system does not have as much to do as it did 50

years ago, because we've increased our efforts to protect our children

from dirt and germs, "

Full article:

Too Clean? Fight Against Germs Fuels Allergy Increase

Jeanna Bryner

LiveScience Staff Writer

LiveScience.comFri Sep 14, 10:45 AM ET

A dose of dirt could be the best medicine for preventing allergies in

kids who've never had them.

While avoiding excessive contact with germs can help prevent the

spread of infections, going overboard with cleanliness could be at

least partly responsible for an increase in allergies among children,

mounting research suggests.

" We've developed a cleanlier lifestyle, and our bodies no longer need

to fight germs as much as they did in the past, " said Marc Mc, a

pediatric allergist at the University of Michigan Health System. " As a

result, the immune system has shifted away from fighting infection to

developing more allergic tendencies. "

More than 50 percent of Americans ages 6 to 59 years are sensitive to

at least one allergen, according to a national survey conducted from

1988 to 1994 by the National Institutes of Health. That's two to five

times higher than rates found in a previous 1976 to 1980 survey.

Recent research has found evidence for the so-called hygiene

hypothesis, which explains how more sterile environments can lead to

higher rates of illness. For instance, scientists in Germany recently

found children exposed to farm animals (and the associated bacteria

and other microbes hiding out there) were about half as likely as

other children to develop the autoimmune illness Crohn's disease.

More animal helpers

Allergies are a reaction by the body's immune system to foreign, yet

generally innocuous, substances, including pollen, mold, animal

dander, dust and certain foods that it deems harmful. If your immune

system has never or rarely detected even the natural background level

of such substances, it can go haywire when contact does occur.

" Allergies are on the rise because our society has changed the way we

live, " Mc said, adding that " as a result, people with allergies

are having children with others who have allergies, which in turn

creates a natural increase in the prevalence of allergies in our society. "

In addition to exposure to farm animals, dogs and cats kept as pets

could also help children avoid developing allergies. A study published

in a 2002 issue of JAMA concluded that children living in a house with

two or more dogs or cats during their first year of life were much

less likely to develop allergic diseases compared with children raised

without pets.

" Epidemiology would suggest if there are 10 cats in the homes, [kids]

are less likely to develop allergies, " said Bruce Bochner, director of

the Division of Allergy and Clinical Immunology at s Hopkins

School of Medicine.

More research is needed, however, to pin down exactly what's going on.

Bochner said one flaw with these studies is that homes with

pet-allergic kids are not likely to have lots of pets.

The dirty truth

From the constant use of anti-bacterial soap for dish- and

hand-washing to air-tight seals around doors and windows, some modern

homes have become shrines to hygiene. Add vaccinations and antibiotics

to the mix and the body's immune system can get too much artificial

reprieve from nature.

" The natural immune system does not have as much to do as it did 50

years ago, because we've increased our efforts to protect our children

from dirt and germs, " Mc said in a statement released this month.

Plus, the atrophy of family size means children get exposed to fewer

germs than the more kid-filled homes of yesteryear. Families with

three or more children, a dynamic that was common decades ago, tend to

have fewer allergies as they are exposed to more bacteria- and

virus-harboring siblings, Mc said.

The battle against bugs doesn't have to come to an end, but finding a

balance between healthy living and clean living is a must, scientists

advise, although Bochner notes the jury is still out on the

over-exposure approach.

" We don't know at this point whether we should be exposing people to

lots of allergens at an early age and get them tolerant [or not], "

Bochner said in a telephone interview. " All we really know is once you

become allergic, since exposure triggers symptoms, the best way to

deal with that is to reduce your exposure. "

Mc says we've gone too far though with germ-avoidance.