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The Hygiene Hypothesis and Autoimmune Disorders (Alzheimer's)
Posted: Tuesday, December 4, 2012 9:49 PM
Joined: 4/24/2012
Posts: 484

I have pulled together supporting evidence for what may be a primary causal factor for Alzheimer's - the elimination of beneficial bacteria from our environment and subsequently our bodies. This "Hygiene Hypothesis," as it is known, is well accepted as contributing to many autoimmune-related disorders like allergies, asthma, inflamatory bowel disease, etc., but now Alzheimer's has also been linked to autoimmune dysfunction, and think rightly so. It makes sense with all that we know about the pathology of Alzheimer's: oxidative damage, inflamation, overactive immune response or lack of immune system function, microbes found in the AD brain, formation of placks (possibly to compensate for oxidative stress), regulation of metals (mercury, copper, aluminum, zinc), link to diabetes, and connections to nutritional deficiencies come to mind. It all ties in to the immune system. Look at the evidence below for the Hygiene Hypothesis and see if you agree that there may be a connection to Alzheimer's.


Mechanisms of Disease: the hygiene hypothesis revisited

  “In industrialized countries the incidence of diseases caused by immune dysregulation has risen. Epidemiologic studies initially suggested this was connected to a reduction in the incidence of infectious diseases; however, an association with defects in immunoregulation is now being recognized. Effector TH1 and TH2 cells are controlled by specialized subsets of regulatory T cells. Some pathogens can induce regulatory cells to evade immune elimination, but regulatory pathways are homeostatic and mainly triggered by harmless microorganisms…These organisms cause little, if any, harm, and have been part of human microecology for millennia; however, they are now less frequent or even absent in the human environment of westernized societies. Deficient exposure to these 'old friends' might explain the increase in immunodysregulatory disorders.” 



The ‘hygiene hypothesis’ for autoimmune and allergic diseases: an update

“According to the ‘hygiene hypothesis’, the decreasing incidence of infections in western countries and more recently in developing countries is at the origin of the increasing incidence of both autoimmune and allergic diseases…Underlying mechanisms are multiple and complex. They include decreased consumption of homeostatic factors and immunoregulation, involving various regulatory T cell subsets and Toll-like receptor stimulation. These mechanisms could originate, to some extent, from changes in microbiota caused by changes in lifestyle, particularly in inflammatory bowel diseases. Taken together, these data open new therapeutic perspectives in the prevention of autoimmune and allergic diseases.” 


Modulating immune responses with probiotic bacteria

“For many years, probiotic bacteria have been known to confer health benefits to the consumer. One possible mechanism for this may be the ability of probiotic bacteria to modulate immune responses. Oral administration of Lactobacillus casei strain Shirota (LcS) has been found to enhance innate immunity by stimulating the activity of splenic NK cells.” 



This next interesting report was in the news today:

Dichlorophenol-containing pesticides and allergies: results from the US National Health and Nutrition Examination Survey

“High urine levels of dichlorophenols are associated with the presence of sensitization to foods in a US population. Excessive use of dichlorophenols may contribute to the increasing incidence of food allergies in westernized societies.” 


Posted: Wednesday, December 5, 2012 10:10 AM
Joined: 12/20/2011
Posts: 217


Serenoa, thanks.


The potential helpfulness of probiotic supplements is very interesting.


And below is an article I just noticed this morning.  It's about 2 new projects to try to discover how different kinds of intestinal microflora affect our health, and how diet and lifestyle may be able to modify them.




Tapping citizen-scientists for a novel gut check



By LAURAN NEERGAARD | Associated Press



WASHINGTON (AP) — The bacterial zoo inside your gut could look very different if you're a vegetarian or an Atkins dieter, a couch potato or an athlete, fat or thin.



Now for a fee — $69 and up — and a stool sample, the curious can find out just what's living in their intestines and take part in one of the hottest new fields in science.



Wait a minute: How many average Joes really want to pay for the privilege of mailing such, er, intimate samples to scientists?



A lot, hope the researchers running two novel citizen-science projects.



One, the American Gut Project, aims to enroll 10,000 people — and a bunch of their dogs and cats too — from around the country. The other, uBiome, separately aims to enroll nearly 2,000 people from anywhere in the world.



"We're finally enabling people to realize the power and value of bacteria in our lives," said microbiologist Jack Gilbert of the University of Chicago and Argonne National Laboratory. He's one of a team of well-known scientists involved with the American Gut Project.



Don't be squeamish: Yes, we share our bodies with trillions of microbes, living communities called microbiomes. Many of the bugs, especially those in the intestinal tract, play indispensable roles in keeping us healthy, from good digestion to a robust immune system.



But which combinations of bacteria seem to keep us healthy? Which ones might encourage problems like obesity, diabetes or irritable bowel syndrome?



And do diet and lifestyle affect those microbes in ways that we might control someday?...



Much more here: 







Lane Simonian
Posted: Wednesday, December 5, 2012 1:16 PM
Joined: 12/12/2011
Posts: 5140

Thank you Serenoa for this information and onward, too.  Probiotics may also limit stress responses in the brain and if this is the case it might be helpful for brain function. 

Posted: Wednesday, December 5, 2012 2:07 PM
Joined: 12/20/2011
Posts: 217

Thanks, Lane.


Here's something else interesting:




Can taking probiotics improve your mental health?



... several neurochemicals (normally produced by the brain) that are also produced by various probiotics in the gut:


Lactobacillus, Bifidobacterium    ---   GABA

Escherichia, Bacillus, Saccharomyces    ---   Norepinephrine

Candida, Streptococcus, Escherichia, Enterococcus    ---   Serotonin

Bacillus, Serratia    ---   Dopamine

Lactobacillus    ---   Acetylcholine



More here: 



Posted: Wednesday, December 5, 2012 7:43 PM
Joined: 4/24/2012
Posts: 484

This is all good information. I thank both of you very much. I'm going to keep going down this road looking for more clues and trying to make connections. Like aromatherapy, this is something I can try not only on my mom but on me too! And it doesn't cost $1,000 a treatment like the Leukine.


I liked the epidemiology associated with the copper theory we discussed a while back (use of copper in western industrialized countries causing AD), but was unconvinced that copper was the causal agent. This hygiene hypothesis seems much more plausible.


Remember the research on blood factors affecting AD:? young blood in old mice improving mental function, as well as the anecdotal account of the blood transfusion improving AD. It seems likely that blood composition is closely related to activity in the gut.


If this is a cause of AD, it still has to be combined with some genetic predisposition which only becomes active in the elderly, like ApoE4. And if AD is autoimmune, why is there no remission as in other autoimmune disorders like Rhuematoid Authritis or Ulcerative Colitis? Is natural remission not noticed in AD because the patient just stops deteriorating for a while?