A few weeks ago, when interviewing ecological medicine pioneer Dr. Damien Downing for our company’s Get Well online intensive on gut healing, I was completely floored by the implications of something he said.

He was showing a slide from the scientific journal Autoimmunity Reviews (Aut Rev, 2015; 14: 479-89) with a title that could well set off nothing less than a revolution in medical thinking.

The paper had the ponderous title of ‘Changes in intestinal tight junction permeability associated with industrial food additives explain the rising incidence of autoimmune disease,’ and Dr Downing had highlighted a section of the abstract where Aaron Lerner, a respected pediatric gastroenterologist from Israel and his co-author Torsten Mattias from a scientific institute in Germany laid out their thesis, implicating the main culprits of intestinal damage:

‘Glucose, salt, emulsifiers, organic solvents, gluten, microbial transglutaminase [a food additive], and nanoparticles are extensively and increasingly used by the food industry, claim the manufacturers, to improve the qualities of food. However, all of the aforementioned additives increase intestinal permeability by breaching the integrity of tight junction paracellular transfer.’

Add to this list, Downing says, excessive alcohol or non-steroidal anti-inflammatory drugs like aspirin or ibuprofen like Advil or Nurofen.

For the uninitiated to the world of medical-speak, ‘breaching the integrity of tight junction paracellular transfer’ is another way of saying that someone has a leaky gut. More of the stuff you eat than should passes through the gut wall, messing up many systems in your body, including your brain.

These authors and Downing were saying, in effect, that the processed food we eat (with all its sugars, salts, emulsifiers, additives, gluten etc), plus all the nanoparticles now so beloved of scientists, not to mention organic solvents from pesticides – in our foods, our gardens and even in our gas exhaust fumes –– are causing our guts to leak. And this, on its own, is responsible for autoimmune disease.

‘And who can put their hand up and say that I’m never exposed to these things?’ asked Downing. ‘And however good you are doing it for yourself, the rest of the world is doing it for you.’

In addition to the above laundry list, Downing said, we need to add glycosate (the pesticide Roundup), which is sprayed on the plants that produce the non-organic food we eat, even the biofuels produced are ‘Roundup-ready,’ he says. ‘It’s coming out of the bus that goes past. So we’re breathing in the darn stuff.’

The result is that the bigger molecules passing through the gut get into the bloodstream, go straight to the liver, which furiously tries to deal with this toxic stuff, makes toxic bile, and eventually dumps it back into the gut, creating a vicious cycle that ultimately wreaks havoc in the body.

‘Within just about 20 minutes of eating the stuff,’ he says, ‘you’re getting a double hit from it as it comes back into the gut and you’re perpetuating the inflammation.’

But besides this toxic vicious cycle, there’s also an allergic one, he says. When these macromolecules pass through the gut wall, they irritate the immune system tissue residing there and set off an inflammatory reaction – what most of us consider allergies or intolerances to food or other substances.

And that, in turn, makes the gut more leaky and the cells lining the gut more vulnerable, and ultimately makes us more and more allergic or susceptible to autoimmune disease.

Consider the case of wheat, which many of us think we’re allergic to. There is a protein called lectin on the surface of wheat that attacks the lining of the gut and sets off inflammation. Inflammation causes a faster turnover of cells, the younger cells are more susceptible to lectins and the whole shooting match continues to get worse.

And that’s the sort of vicious cycle that ultimately leads to autoimmune disease like inflammatory bowel disease, says Downing. A leaky gut also disrupts the exquisite communication that occurs between a community of cells, keeping rogue cells (like cancer cells) in line.

What this means, he says, is that all of us are vulnerable to damage from our gut and potential candidates for allergies or autoimmune disease.

So all this sounds pretty hopeless until you recognize that there’s a simple way to heal a leaky gut, something as easy as swallowing a pill or lazing at the beach.

As Downing shared, yet another of the seemingly inexhaustible roles the extraordinary vitamin/hormone vitamin D has is its ability to protect the integrity of cells.

Laboratory research at the University of California at San Diego revealed that taking the active form of vitamin D actually closes those open junctions in a leaky gut.

It also results in greater diversity of bacteria in the gut, which produce a beneficial fatty acid called butyrate, essential for keeping this gut lining intact.

Conversely, when you are vitamin D deficient, as most of us are who have been staying indoors because of Covid restrictions or slathering on sun cream when we do go out, those junctions don’t close very well.

The reason that I was blown away by Downing’s talk is that it quietly demolishes most received wisdom about autoimmune illness and of allergies.

In Downing’s view, few of us are inherently allergic to certain foods. What we are actually allergic to is modern life: processed or chemically manipulated food, lack of outdoor living, the ubiquitous chemicals we inhale or ingest without thinking.

He’s also saying that allergies or autoimmune disease doesn’t have to be a life sentence. ‘Nine people out of 10 who have a wheat reaction in the gut, it’s temporary and it can be easily fixed,’ says Downing. You just have to cut out the substance for a while and clean up the rest of your diet.

And these days, I’d add, that also means cleaning up the rest of your life whenever you can.