The Immune Disease Epidemic and the Hygiene Hypothesis

Once upon a time, there were no doctors.  Women had as many kids as they could because many of the kids would die.  The women often died too.  All children were born vaginally and breastfed.  No one had toilets, feces got into the water supply and caused illness and death.  Children were exposed to parasites through feces they would step in.  Eventually new knowledge and technology such as the invention of the microscope changed that.  Sanitation and toilets became standard.  Pasteur did experiments that proved germs existed, and he discovered ways to protect people.  People started living longer, vaccines and antibiotics were invented, C-sections became a valid option.  Handwashing was discovered to save women who were giving birth in hospitals.  Soon, children started receiving vaccinations and child mortality dropped.  The polio vaccine saved many children from paralysis.  Antibiotics became routine for childhood and prenatal infections.  Our microbiome was drastically affected by these changes.

Babies are born sterile and get their gut flora from mom’s vagina.  Then gut flora is selectively built up by prebiotics and antibacterial substances in breastmilk.  When a woman’s vaginal flora is disrupted, it makes her more vulnerable to STD’s that can hurt her or her baby.  If she is given antibiotics to kill the bad organisms, the normal flora may not be re-established.  Some women are given antibiotics for things such as group B strep right before delivery.  Or the mom might need a C-section.  Many babies miss their first taste (literally) of good healthy microbes from mom’s vagina.  If the baby is not breastfed, it misses out on that chance to develop a normal gut flora.  Breastfed and formula fed babies have 2 different types of flora.

We have clean water and toilets.  Dirt is viewed as a horrific thing.  Many children grown up in urban areas with little greenspace.  The little greenspace left is sprayed with herb/pest-icides, and marked with a sign stating “keep off the grass”.  This has bad results not only for our immune systems but also for learning.  Children need to play outside.

Probiotics are known to help immunity, they can reduce the rate of developing allergies and the chances of getting a cold.  This is now a big business, and we haven’t even reached the tip of the iceberg.  The human microbiome project is categorizing all the organisms that live in the human body.  When/if they categorize the ones that live in our intestines, we will have much better quality probiotics than the ones we have now.

It’s not just bacteria that are important to our immune system.  We used to have lots of exposure to parasites.  Fighting parasites was a high priority to our immune system.  And the parasites evolved along with us.  The ones that are adapted to living inside humans have various strategies for evading our immune system.  Soil transmitted helminths (worms) live in the intestines.  The body’s defense against parasites is allergy and inflammation, so these worms release chemicals that selectively turn off parts of our immune system.  If they turned off the whole thing, we would die, and so would the worms.

Helminths are being studied as a “new therapy” for immune conditions such as autoimmune disease and allergy.  The more I read about them, the more I think that this is a beautiful idea.  Two types in particular are very attractive probiotics.  Human hookworms, a type called Necator americanus; and whipworms, called Trichuris Trichiura (human version) and Trichuris Suis (pig version [TSO for short]).  They cause few symptoms when controlled doses are given, and they stay active in the body for a long time, up to several years for human whipworm and hookworm.  It’s like taking a steroid without the side effects.  Maybe children should be given these in controlled doses to mimic the natural exposure they would get if we didn’t have sanitation.  Especially in families at high risk of allergy and autoimmune disease.  An ounce of prevention.

These soil transmitted helminths are still common in the third world.  According to the CDC, 500-700 million people are infected with each (hookworm and whipworm).  The major problems they cause are anemia leading to developmental delays if the infected children are malnourished.  Diarrhea is another symptoms of heavy infection.  Children who are given medication to kill their worms often develop allergies.  Even pregnant women who are de-wormed during pregnancy have a higher chance of having allergic kids.  I think that helminth deficiency is probably behind the huge increase in allergy, autoimmune disease, and autism.  In fact, TSO has helped an autistic young man, and sparked a clinical trial.

Scientists started to notice that allergies and autoimmune disease are basically non-existant in countries where people still have worms.  Researchers began experimenting with replacing the worms in people with inflammatory bowel disease.  The worms cured many of the people and were safer and had fewer side effects than the drugs people were taking.  Helminths have been shown to help Crohn’s disease, ulcerative colitis, allergies, asthma, and MS.  There are active clinical trials using helminth therapy for celiac disease, peanut allergy, autism, and MS.

I hypothesize that helminth replacement would help in eosinophilic esophagitis and EGID’s.  For one thing, the eosinophilic response is designed to fight off parasites, whether in the skin, lungs, or GI tract.  There are corresponding allergic diseases where you see eosinophils in the skin (eczema), lungs (asthma), and GI tract (EGID’s).  Hookworms release chemicals that block eosinophils from getting into tissue.  Whipworms also release chemicals that reduce intestinal and brain inflammation.  Both of these worms cause the creation of Treg cells.  Because hookworms can block eosinophils from getting into tissue, they have the potential to cure EGID’s.  In fact, the reason that rates of EGID’s are increasing could be due to altered gut bacteria and helminth deficiency.  Another interesting point is that people get eosinophilic gastroenteritis when infected with certain non-human parasites, but not when infected certain human parasites, showing that the human parasites can inhibit EGID’s.

If excessive hygiene is the cause of the epidemic of immune disease in civilized countries, what then is the solution?  For a start, reducing antibiotic use.  They should be a tightly controlled substance, reserved for only the most extreme cases.  The super-bug epidemic plus the immune epidemic is plenty to say that we need to stop giving out antibiotics like candy.  We should continue to study the types of gut bacteria and type them so we can make better probiotics that resemble real gut bacteria, not just a few strains like in yogurt.  Limit vaccines to the most dangerous bugs, not offer new vaccines out of the convenience of not getting sick (cough chickenpox), and make existing vaccines safer by eliminating additives not related to the vaccines.  We should eat real food, and ban pesticides, hormones, antibiotics, and xenobiotics in our food and water supply.  We should find a way for children to be exposed to low doses of intestinal parasites, without giving up the benefits of toilets and sanitation.  We should ban antibacterial chemicals in household products and hospitals and just use 10% bleach or diluted vinegar for our cleaning needs.  We should ban germfearmongering advertisements from cleaning companies (cough Lysol).  Mothers should be given a paid year off after the birth of each child so they can breastfeed them for a full year.  Baby formula companies should not be allowed to advertise, and formula should also be restricted to prescription only.  Human milk banks should be started.  There should be free childcare and sick childcare available so mothers would not be tempted to get antibiotics for their kids to prevent being penalized for their sick kids.  Drug companies should not be allowed to advertise, period.  The US healthcare system should be revamped to promote wellness instead of procedures and medications.  I know these ideas are radical, but if the capitalists only knew how much money these rules would save us, they would be all over them.  Health and wealth for all.

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