Navigation Links
A Little Dirt May Be a Good Thing
Date:9/9/2011

By Dennis Thompson
HealthDay Reporter

FRIDAY, Sept. 9 (HealthDay News) -- Good hygiene has saved millions of lives, protecting people from countless bacterial and viral infections, according to the U.S. Centers for Disease Control and Prevention.

But there is growing concern that strict adherence to good hygiene, though a valuable means of protecting health, has left humans open to other forms of illness.

Proponents of the "hygiene hypothesis" believe that reduced exposure to bacteria, viruses and parasites have impaired the immune system's ability to properly respond to environmental challenges.

Researchers have identified the hygiene hypothesis as a possible cause or exacerbating factor in a number of illnesses and medical problems, said Dr. Graham A.W. Rook, a professor in the department of infection at the Centre for Clinical Microbiology at the University College London. These include:

  • Severe allergic reactions.
  • Gastrointestinal disorders, such as inflammatory bowel disease and Crohn's disease.
  • Autoimmune disorders, such as type 1 diabetes and multiple sclerosis.

"The evidence for all this is very, very powerful," Rook said. "It's very easy to show if you live on a farm or keep a dog, you're less likely to have these disorders. If you are the youngest child in a big family, you're less likely to have these disorders."

The hygiene hypothesis has its roots in the theory of evolution, he said.

"The bottom line is organisms that were present in mud, untreated water and feces were with us right from the start of humanity," Rook explained. Proponents of the hygiene hypothesis believe that the human body adapted to these organisms and began using them as a means of training the immune system.

"What has happened over the course of evolution is, because these bugs had to be tolerated, they came to activate the tolerance of the immune system," Rook said. "They are the police force that keeps the immune system from becoming trigger-happy. Basically, the immune system is now attacking things it shouldn't be attacking."

Dr. Mitchell H. Grayson, an associate professor of pediatrics at the Medical College of Wisconsin in Milwaukee, said that the hygiene hypothesis is most strongly linked to an increase in allergic diseases and asthma.

"It's thought to have something to do with the way your immune system develops and is programmed," Grayson said. Bacteria in the environment teach an immune response to allergens that is more moderate and less severe. "In the absence of these bacteria, the immune system is thought to become more prone to allergic disease," he said.

Rook said that other researchers have used the hygiene hypothesis to show that parasitic infections can aid in the treatment of such conditions as multiple sclerosis and Crohn's disease.

Argentinean researchers, for instance, have shown that the presence of intestinal parasites can moderate the progression of multiple sclerosis. Follow-up studies indicated that, when people were treated for their parasitic infection, they had a relapse of MS.

A research team at the University of Iowa found similar results related to Crohn's disease, showing that intestinal parasites helped regulate the autoimmune reaction that causes the intestinal disorder.

On the flip side, such revelations carry risks. Doctors are concerned that some might use the hygiene hypothesis as an excuse to abandon good hygiene, causing a surge in diseases such as dysentery and cholera.

"Public health and sanitation has been the single greatest improvement in our life expectancy," Grayson said. "I would not recommend living less cleanly."

On the other hand, tolerance of a little dirt here and there won't hurt.

"If your kids come back from the garden with a little mud on their hands, it's not a bad thing," Rook said. "They don't necessarily have to wash their hands before picking up a sandwich."

In general, though, it's wise to maintain good overall hygiene, he said, and wait for the scientists to figure all this out. Larger studies are underway to determine the exact mechanism by which bacteria and parasites are causing the immune system to moderate its response, Rook said.

"We need to figure out how to replace what is good from the microbiological environment while maintaining the advances of good hygiene so we can get the best of both worlds," Rook said.

More information

The U.S. National Institute of Allergy and Infectious Diseases has more on the role of microbes and bacteria in sickness and health.

SOURCES: Graham A.W. Rook, M.D., professor, department of infection, Centre for Clinical Microbiology, University College London, London, U.K.; Mitchell H. Grayson, M.D., associate professor, pediatrics, Medical College of Wisconsin, Milwaukee, Wis.


'/>"/>
Copyright©2010 ScoutNews,LLC.
All rights reserved  

Related medicine news :

1. As Venus Williams Bows Out of U.S. Open, Little-Known Disease Takes Center Court
2. A Little Exercise Goes a Long Way to Cut Disease, Death Risk
3. Even a Little Exercise Helps the Heart, Study Finds
4. Theres a Little Neanderthal in Most of Us
5. High School Kids Get Too Many Sugary Drinks, Too Little Exercise: CDC
6. Too Little Sleep in Preschool Years May Predict ADHD
7. Poll Finds Little Support for GOP Plan to Privatize Medicare
8. Bathroom Injuries a Little-Known Problem
9. Chiropractic manipulation results in little or no risk of chest injury
10. Little Evidence That Diet, Lifestyle Cuts Alzheimers Risk
11. Even a Little Exercise May Protect Against Colon Polyps
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
A Little Dirt May Be a Good Thing
(Date:5/24/2017)... ... May 24, 2017 , ... Last month, representatives ... hospital employees, and town officials to celebrate the grand opening of the 87,000 ... Rendina as part of its ongoing relationship with RWJBarnabas Health, New Jersey’s largest ...
(Date:5/24/2017)... ... May 24, 2017 , ... Dr. Alan I. Benvenisty, MD is dual board ... He is known for his distinguished expertise and experience in the diagnosis and treatment ... training in treating renovascular disease and aortic aneurysm . He is known for ...
(Date:5/24/2017)... ... May 24, 2017 , ... ... and interpretation, has received U.S. Food and Drug Administration (FDA) 510(k) clearance ... scalable and secure cloud platform for medical image management. At the core is ...
(Date:5/24/2017)... ... 2017 , ... Dr. Manju R. Kejriwal, a leading Ohio dentist, is now ... a referral. Dr. Kejriwal understands the emotional and financial toll traditional orthodontics can take ... Patients no longer need to feel the esthetic effects of wires and brackets when ...
(Date:5/24/2017)... ... May 24, 2017 , ... STATEMENT OPPOSING ... vehemently opposed to Donald Trump’s budget, “A New Foundation for American Greatness—President's Budget ... demonizes the poor, marginalizes underserved populations, undermines productivity, and destroys the social safety ...
Breaking Medicine News(10 mins):
(Date:5/15/2017)... , May 15, 2017 Enterin Inc., a ... and developing novel compounds to treat Parkinson,s disease (PD), ... study is a Phase 1/2a randomized, controlled, multicenter study involving ... It will enroll 50 patients over a 9-to-12-month period. The ... in 10 patients with PD. Participating sites include ...
(Date:5/11/2017)... , May 11, 2017  Thornhill Research ... has been awarded an $8,049,024 USD five-year, firm-fixed-priced, ... through the Canadian Commercial Corporation (CCC) ( ... Anesthesia Systems to administer general anesthesia to patients ... "The US Marine Corps have been ...
(Date:5/10/2017)... , May 10, 2017 Global Health Intelligence ... Latin America , published its 2017 ranking of ... is based on extensive data analysis from GHI,s hospitals ... hospitals database for the region. The GHI database covers 86% ... offering more than 130 data points for each institution in ...
Breaking Medicine Technology: