What Is '70% of Our Immune System' DOING in Our Digestive Track?

There is this yogurt commercial, that shall remain nameless, that brings up an interesting fact. A full 70% of our immune system, is actually found in our digestive track.

As I said, it shall remain nameless. So I don’t have a cite. But I assume it is an established medical fact. I mean, why would they want to deceive us (besides wanting to sell us their product, and all that)?

My question is simple: What on earth is 70% of our immune system doing, in our digestive track? Shouldn’t it be in our blood system and organs, protecting us from dangerous pathogens?

And if it is mostly in our digestive track, it sure doesn’t seem to be doing its job. We have plenty of friendly bacteria there. It doesn’t target that. But still, outside bacteria is still outside bacteria, isn’t it? Also, I get mild cases of food poisoning all the time. So it certainly doesn’t seem to be helping me? What is it doing there?


Sounds very scientific and factual, doesn’t it?

Sounds like Marketing Bullshit, to use the technical name for such claims.

My favorite, however is “I’m not a doctor, but I play one on TV”.

Hey - same thing, right? I’m sure your knowledge of Medicine is as good as that of real doctors!

“70% of your “immune system” lives in your gut” just doesn’t even come close “Same As A Real Doctor”.

Come back when you have a real classic of “Marketing Horseshit, Medical Topic” to share.

How do you suppose dangerous pathogens normally get into your blood system and organs?

It’s of course not a medical fact, but the digestive system is one of the places in the body where very permeable parts of our exterior (remember your topology, if we ignore nose and ears the human body is a donut) is constantly exposed to pathogens.

A large part of our immune system is closely associated with our digestive sytem.
Gut-associated lymphoid tissue (GALT) is indeed a major part of our immune system.
As part of the Mucosa-associated lymphoid tissue (MALT) it hosts lymphocytes, macrophages and other cells that participate in immune responses. Considering that our digestive system is laden with bacteria, it makes sense that it is under strict supervision by the immune system. The Gastrointestinal Immune System

The problem with claims like this (which may be true in a quantitative sense) is that they imply that the product(s) being sold are going to boost one’s immune system, which is another kettle of (rancid) fish.

“Gut health” is a big buzzphrase these days, and marketing is way ahead of the science.

The digestive tract is where stuff from outside the body is brought inside the body. It’s important to regulate what gets in and what doesn’t. It doesn’t work perfectly, but it does work most of the time.

Your gastrointestinal digestive tractstarts basically at the mouth and end at the anus.

That’s the most exposed part of your body to foreign intruders, even tho it’s internal, besides the skin and the lunges for breathing.

One problem with taking antibiotics unnecessarily is that they kill off large numbers of beneficial bacteria in our guts.

Most of the problem is deciding what measure to use to determine the “70%”. The acid in your stomach kills a lot of pathogens – does that make it a part of the immune system?

It’s a statement that can be found in the medical literature. And then misapplied to make it more general than it actually is.

The most relevant article is Allergy and the gastrointestinal system from Clin Exp Immunol. 2008 Sep; 153(Suppl 1): 3–6.

When you read the full article, however, you soon realize that it refers specifically to food-based allergic reactions. That is not the “immune system” as most people generally understand the term, which is generally taught as the white blood cells.

It shouldn’t be surprising that the gut plays a part in defending against food-based allergens. That article explains the mechanisms - as far as they are known, which isn’t all that far - and the possible consequences.

The danger comes from taking a specialized medical finding and applying it to areas where it doesn’t belong. This claim is technically true, which I define as a fact so wrenched out of context that it appears to mean the opposite of what it does.

On the other hand, the digestive track is the route you take through the duodenum, making a hard left at the sphincter of Oddi in order to get to the pancreas before it closes for the night.

Does that make the yogurt commercial the real digestive tract?

The prime function of the stomach acid (Gastric Acid) is to digest your food, but it also helps to inhibits microorganisms from growing due to the acid environment.