Hygiene Hypothesis

  • Food allergies linked to hygiene hypothesis? ‘If fewer allergies is more infection, no parent would expose their child to more infection'

    Posted: January 4th, 2012 - 6:04am by Doug Powell

    People from well-educated families are almost twice as likely to suffer from some dangerous food allergies as others — possibly because their bodies’ natural defences have been lowered by rigorous hygiene and infection control, suggests a new Canadian study.

    The research from McGill University also found that immigrants were about half as likely to be afflicted by the allergies, perhaps reflecting differences in diet and environment between their countries of origin and Canada.

    The study, just published in the Journal of Allergy, was meant to address an enduring medical mystery: Why have so many people in certain industrialized countries developed violent reactions to peanuts, shellfish and other foods in recent decades?

    The link to higher education may be explained by what is called the hygiene hypothesis, the unproven idea that smaller families, cleaner homes, more use of antibiotics to treat infections and vaccines to prevent them have curbed development of the immune system, said Dr. Moshe Ben-Shoshan, who led the research. That in turn could make some people more susceptible to allergy.

    If the hypothesis does actually explain some food reactions, though, parents may not be able to do much about it, admitted the allergist at Montreal Children’s Hospital. The benefits of such health products as antibiotics and vaccines easily outweigh the risk of children developing serious allergies, said Dr. Ben-Shoshan.
    “We can’t suggest we become dirtier and expose our children to more bacteria,” he said. “If the price of having fewer allergies is more infection, I don’t know any parent who would expose their child to more infection.”

    The study’s findings are far from conclusive but they, and the hygiene hypothesis as an explanation, seem plausible, said Dr. Stuart Carr, president of the Canadian Society of Allergy and Clinical Immunology. He also cautioned, however, that translating the knowledge into preventive action would be complicated.

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    Allergies  |  1 Comment
    Allergy, Education, Food, Hygiene Hypothesis
  • Local food is not inherently safer food

    Posted: August 6th, 2009 - 6:37am by Doug Powell

    The idea that food grown and consumed locally is somehow safer than other food, either because it contacts fewer hands or any outbreaks would be contained, is the product of wishful thinking.

    Barry Estabrook of Gourmet magazine is the latest to invoke the local is pure fantasy, writing,

    “There is no doubt that our food-safety system is broken. But with the vast majority of disease outbreaks coming from industrial-scale operations, legislators should have fixed the problems there instead of targeting small, local businesses that were never part of the problem in the first place.”

    As soon as someone says there’s “no doubt” I am filled with doubt about the quality of the statement that is about to follow.

    Foodborne illness is vastly underreported -- it's known as the burden of reporting foodborne illness. Someone has to get sick enough to go to a doctor, go to a doctor that is bright enough to order the right test, live in a state that has the known foodborne illnesses as a reportable disease, and then it gets registered by the feds. For every known case of foodborne illness, there are 10 -300 other cases, depending on the severity of the bug.??????

    Most foodborne illness is never detected. It’s almost never the last meal someone ate, or whatever other mythologies are out there. A stool sample linked with some epidemiology or food testing is required to make associations with specific foods. ??????Newsweek has an excellent article this week about the U.S. Centers for Disease Control and its Disease Detective Camp, where teenagers learn how to form a hypothesis about a disease outbreak and conduct an investigation. The key lies only partly in state-of-the-art technology. At least half the challenge is figuring out the right questions to ask. Who has contracted the disease? Where have they been? Why were they exposed to this pathogen?

    Maybe the vast majority of foodborne outbreaks come from industrial-scale operations because the vast majority of food and meals is consumed from industrial-scale operations. To accurately compare local and other food, a database would have to somehow be constructed so that a comparison of illnesses on a per capita meal or even ingredient basis could be made. ???

     

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    Food Safety Policy, Raw Food  |  2 Comments
    Cdc, Disease Detective Camp, Hygiene Hypothesis, Industrial, Local, Questions
  • CHUCK DODD: Eating dirt can be bad for you

    Posted: January 29th, 2009 - 10:17am by Doug Powell

    New York Times journalist Jane Brody suggests that eating dirt is an instinctive behavior in humans. In her article, Eating dirt can be good for you - just ask babies, she interviewed researchers who think people should eat dirt in order to stimulate their immune system.  Brody says that immune system disorders such as asthma and allergies have risen significantly in the United States. 

    Although allergies do appear to be on the rise, the awareness of allergies, the ability to diagnose allergies, and the number of people at risk (the U.S. population) have also risen significantly. 

    The director of gastroenterology and hepatology at Tufts Medical Center in Boston, Dr. Joel Weinstock, said in the interview,

    "There are very few diseases that people get from worms. Humans have adapted to the presence of most of them. … Children should be allowed to go barefoot in the dirt, play in the dirt, and not have to wash their hands when they come in to eat…let kids have two dogs and a cat, which will expose them to intestinal worms that can promote a healthy immune system.”

    Dr. Weinstock, I’m sure glad you aren’t my doctor. 

    I agree that immune systems are naturally stimulated by various exposures to the environment, and that Americans use too many antibacterial products, but I question Dr. Weinstock’s knowledge of zoonotic diseases.  Intestinal parasites from animals that infect humans, since many are not adapted to humans, often leave the intestines and migrate through the body.  There are approximately 10,000 human cases of larva migrans in the U.S. each year.  Unfortunately, most of these cases are in children, and a few of these kids die.

    Eating dirt is an instinct?  Not for me.  Babies eat dirt because they don’t know better.  Some may think that bad behavior is an instinct, but calling bad behavior an instinct doesn’t excuse it.  Bad advice shouldn’t be excused either. 

    Dirt may have poop in it, so don’t eat it.


     

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    Baby, Chuck Dodd, Dirty, Eating Dirt, Hygiene, Hygiene Hypothesis, Kids, Reheating Leftovers
  • CRAIG ANDREW-KABILAFKAS: This article made me barf

    Posted: January 28th, 2009 - 9:08pm by Ben Chapman

    I'm usually immune to many of the crazy notions that appear in FSnet, but having been touched by the recent and tragic Pseudomonas aeruginosa-linked death of Brazilian model Mariana Bridi, reading  Eating dirt can be good for you - just ask babies  made me barf. Surely it's not too hard to understand that the evolutionary advantage Jane Brody references is Darwin's survival of the fittest.  This means that the weak do not survive, they die.  Yes, it is better for humanity in the long run, but are there really parents alive today that want to play Russian roulette with their infants? 

    Not me.

    I know that 99% of the food that my kids eat is not sterile.  If tested it in a food microbiology lab there will be a bacterial count, but hopefully no pathogens.  I know that my mouth has trillions of bacteria resident in it even though I brush and floss my teeth twice daily.  I know that the air is not sterile and that my nose connects to my throat.  Some of the bacteria filtered by my nostrils will make their way into my throat and stomach.  Same with my kids.  I want my kids to survive and thrive so I get them to practice good personal hygiene.  I teach them about understanding and avoiding risk.  I think that it is an instinctive behaviour for children to crawl, but I prevented my children from crawling on the road because they had no concept of the risk of being hit by a car.

    I also stopped them from putting dirt into their mouth.  They are still alive, strong and healthy today.  Bacteria don't have discretion.  Mariana Bridi was in her prime and yet could not withstand the attack of a potent and pathogenic invader.  All of our knowledge, technology, and intellectual effort could not defeat her Pseudomonas aeruginosa infection.  Is society better off for her passing? 

    Bridi's untimely death has affirmed my knowledge that survival of the fittest is still in play.  It can also serve to remind that we are not good judges of what is truly meant by "fittest".  Your child may look healthy and robust, but by exposing her to pathogens that are readily found in dirt and pet faeces you are conducting a life threatening experiment. You are playing Russian roulette with your child's life and that is not the way to ensure survival. 

    Practice good personal hygiene, good parenting and just hope that you and your family are fortunate enough to avoid the deadly, painful and destructive pathogenic bacteria that surround us.

    Craig is a food microbiologist working as a food safety consultant across the Australasian region.
     

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    Bridi, Hygiene, Hygiene Hypothesis, Mariana