Because of spam, I personally moderate all comments left on my blog. However, because of health issues, I will not be able to do so in the future.

If you have a personal question about LI or any related topic you can send me an email at I will try to respond.

Otherwise, this blog is now a legacy site, meaning that I am not updating it any longer. The basic information about LI is still sound. However, product information and weblinks may be out of date.

In addition, my old website, Planet Lactose, has been taken down because of the age of the information. Unfortunately, that means links to the site on this blog will no longer work.

For quick offline reference, you can purchase Planet Lactose: The Best of the Blog as an ebook on or Almost 100,000 words on LI, allergies, milk products, milk-free products, and the genetics of intolerance, along with large helpings of the weirdness that is the Net.

Saturday, March 01, 2008

Immune System Not in Your Gut

"Probably 50% of our direct immune system resides in or around the gut."

"Fully 60 percent of your adaptive immune system resides in your small intestine."

"70% of our immune system is located around the digestive system."

"About eighty percent of the full force of your defensive immune system resides in your intestines or gut."

With these "facts" floating around the internet, it was inevitable that someone concerned about milk allergy would get the idea that "the immune system resides in the gut." Sure enough, I saw this statement earlier today.

It's not true. At best, it's a misunderstanding of the role that the digestive system plays, but even that overstates the truth. In reality, it's sheer pseudoscience perpetrated by new age quacks who want to sell you their digestive enzymes or supplements or herbs or even weirder stuff. (Yes, of course our old friend NAET peddles this nonsense. Just one of many.)

The excuse that is given on these sites is often something they call "leaky gut syndrome." The mainstream medical community doesn't recognize this syndrome, and it's tough to find any medical journal articles that even address it. That doesn't matter to the alternative medicine gurus. Leaky gut appears to be yet another of the quackeries that started in the UK, that haven of ignorance about food, nutrition, and digestion, and was snapped up here in America by those looking to make a quick buck out of other peoples' ills.

It's as perfect a scam as can be imagined. Because it has no recognized existence alternative practitioners are free to invent any set of symptoms and cures they want to sell. Since all cures will be anecdotal, and many will simply involve taking an offending food out of the diet anyway, the cures might lead to an alleviation of symptoms for some. If they do, fine, that's a testimonial. If not, the sufferer will go on to another "cure." Heads they win, tails you lose.

For information that sticks to the real world of medicine, How Stuff Works has a good, plain-language explanation of the immune system. (Seventeen pages and no mention of leaky gut!)

Another straightforward set of pages are those on Allergic Reaction at

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Anonymous said...

You're a moron. Try telling that crap to all the people who I've helped increase their overall health with proper nutrition. Your immune system IS primarily based on your gut and what you put into your body. But you go ahead and say otherwise because I'm sure you've done your own research...or have you? Like I said, moron.

Anonymous said...

Yes I have to agree with the anonymous post'r. You have to be a complete idiot to believe what this guy is trying to say. THERE ARE TONS AND TONS OF "REAL" STUDIES THAT SHOW 70-80 PERCENT OF THE HUMAN IMMUNE SYSTEM IS LOCATED IN OUR GUT. THERE ARE ALSO NUMEROUS STUDIES LINKING GUT FLORA IMBALANCE TO AUTOIMMUNE DISORDERS. This is the type of guy that will tell you that living a 100% sterile life is the most healthy way to live too. WRONG!!! he will probably also try and tell you that the human microbiome doesn't exist. WRONG!!!! it does. LISTEN FOLKS.....THE ONLY PSEUDOSCIENCE TAKING PLACE HERE IS THIS BLOCKHEAD...

Steve Carper said...

There are "real studies"? That's terrific. Please give me links to them. To real peer-reviewed medical journals. That have an actual definition of "immune system." And can tell me 70% of what.

I won't be holding my breath, though.

Anonymous said...

Here is a study check out the link:

Here is the abstract:

The gastrointestinal system plays a central role in immune system homeostasis. It is the main route of contact with the external environment and is overloaded every day with external stimuli, sometimes dangerous as pathogens (bacteria, protozoa, fungi, viruses) or toxic substances, in other cases very useful as food or commensal flora. The crucial position of the gastrointestinal system is testified by the huge amount of immune cells that reside within it. Indeed, gut-associated lymphoid tissue (GALT) is the prominent part of mucosal-associated lymphoid tissue (MALT) and represents almost 70% of the entire immune system; moreover, about 80% of plasma cells [mainly immunoglobulin A (IgA)-bearing cells] reside in GALT. GALT interacts strictly with gastrointestinal functions in a dynamic manner; for instance, by increasing intestinal permeability in replay to particular stimulations, or orientating the immune response towards luminal content, allowing either tolerance or elimination/degradation of luminal antigens, or sometimes provoking damage to the intestinal mucosa, such as in coeliac disease or food allergy. The immune mechanisms implicated in these actions are very complex and belong to both innate and adaptive immunity; innate immunity supplies an immediate non-specific response that is indispensable before specific adaptive immunity, which needs 7–10 days to be efficacious, takes place. The results of their interactions depend upon different contexts in which contact with external agents occurs and may change according to different genetic settings of the hosts.