Immunity Is Decided in the Gut

"I think it's because my immunity has dropped."

It's something I hear often, and something I often say myself. But this phrase is a little strange. If immunity has dropped, what exactly has dropped, and by how much? To raise it, what would you raise?

I believe that to answer this question, we first have to ask where the baseline of immunity is set.

Where are immune cells most concentrated?

The answer is unexpected. It's not the blood, not the lymph nodes, not the spleen.

The place in the body where immune cells gather in the greatest numbers is the gut.

The reason is simple. The gut is the inside of the body and yet also the place that meets the outside. Everything we eat, and the countless bacteria and unfamiliar substances that come in along with it, face the body across this single thin membrane.

All day, for a lifetime, without rest, it has to make judgments. Should this be accepted, or blocked?

That the body has placed the most immune cells in the gut is, therefore, only natural.

The gut trains immunity every day

What happens in the gut is not only fighting. Something far more interesting takes place.

The bacteria in the gut constantly shed substances like fragments of their cell walls. A tiny amount of some of these crosses the gut wall into the body. The same goes for signaling substances released from damaged cells.

These small signals continuously tell the body's immune system, "This is what the outside is like right now."

In other words, the gut is re-calibrating the baseline of the immune system anew every day. How sensitively to react, how much to tolerate — it learns this here.

So what changes?

Once you stand at this viewpoint, things that seemed unrelated connect together.

When the gut begins to leak — an amount of substances that shouldn't have crossed over crosses over. The immune system stays in a constant state of alert, and a low-grade inflammation lingers throughout the body. The state of being continuously tired without being able to pinpoint exactly where it hurts is not unrelated to this.

When the composition of the gut microbiota is disrupted — the content of the training changes. It reacts to what it should tolerate, and misses what it should react to. This point is often cited as the background to the rise in allergies and autoimmune conditions.

When the gut doesn't move well — in the places where things stagnate, the composition of bacteria shifts, and the mucosa gets irritated.

Herbal medicine, too, diverges here

I've mentioned this before in another post. A large portion of the active ingredients in herbal medicine are not absorbed as they are; they are absorbed only after the microbes of the large intestine work on them and convert them into an active form.

When you overlay these two facts, they form a single picture.

The gut is the place where medicine awakens, and at the same time the place where the baseline of immunity is set.

When the gut is bad, even good medicine cannot exert its power, and the baseline of immunity is disrupted as well. That's why, the more long-standing an illness is, the more I look at the gut first. It looks like a detour, but it's actually the shortcut.

So should I just take probiotics?

This is a question I get often. It can help, but I don't tell people that it alone is enough.

The gut microbiota is not a simple ecosystem that changes just because you add a few species. More important than what you add is what kind of environment you create.

• Does the gut move well — when it stagnates, the composition changes
• Is the pressure inside the abdomen appropriate — when pressure is high, the gut moves less
• Does the breath reach all the way down to the belly — the rise and fall of the diaphragm pushes the gut
• Is the autonomic nervous system stable — in a state of tension, the gut doesn't do its work

That's why, when I treat the gut, rather than adding bacteria, I focus on creating the conditions for the gut to move and recover.

Why your stomach hurts when you're tense

The gut and the autonomic nervous system are densely connected. It's no coincidence that you get a stomachache when you're tense, and that your sleep grows shallow when your gut is bad.

When the body judges that there is danger, it puts digestion off for later. When you have to run away, there's no room to digest a meal. But when this state becomes chronic, the gut is always left with its work postponed.

The place that sets the baseline of immunity is always in a state of postponed work.

That's why, when people with a shaky autonomic nervous system also have poor digestion and frequent minor ailments, I don't see them as three different illnesses. I see them as a single flow that began from one place.

Finally

That the gut plays a large role in immunity is a well-known fact. However, the way of reducing the word "immunity" to the condition of the gut still carries the risk of oversimplification, and I know that. Immunity is not explained by the gut alone. Genetics, age, sleep, and stress are all involved.

And to someone who comes worried about immunity, when testing is needed first, I recommend testing. If an autoimmune disease or immunodeficiency is suspected, that clinical care takes priority.

But before you go searching for a "medicine that raises immunity," I would like you to look, just once, at where that immunity is being tuned every day. Usually the answer is not somewhere deep inside the body, but in this morning's digestion and bowel movement.