Why may nutrient deficiencies lead to food sensitivities?

Indeed, nutrient deficiencies can increase our risk for food sensitivities and intolerances.

Why?

The answer is complex, but what you need to remember is this:

There are hundreds of thousands of mechanical and biochemical pathways involved in digestion, assimilation and elimination of food substances, and all of them require essential nutrients to work.

So if we see a lack or reduction in a certain nutrient, that digestive pathway or mechanism it relates to will be compromised or impaired.

This can lead to an inability (or reduced ability) to digest that food substance, or to assimilate it, or to utilise it, or get rid of it, or to neutralise it, or to synthetise it into something else.

And when the body is unable to digest, assimilate, utilise, get rid of, neutralise or synthetise a foodstuff or food compound, it means that we are unable to tolerate it (food intolerance) or to deal with it properly (food sensitivity and/or allergy).

In essence, food intolerances, sensitivities and allergies can be triggered by a host of complex mechanisms with numerous convoluted pathways (direct and indirect) which scientists are still investigating - and we're just touching on the tip of the iceberg in here!

For example, one of these biochemical pathways involved in digestion, assimilation and elimination is bile.

But if we don't have the essential nutrients and the precursors needed to produce good quality bile or sufficient bile, it won't work optimally. Meaning we won't be able to digest, assimilate, utilise, get rid of, neutralise or synthetise the foodstuffs it's supposed to deal with.

Also, maintaining good gut-barrier function is needed to reduce the risk of food sensitivities and intolerances.

So, for instance, bile not only epigenetically boosts the host's production of antimicrobial factors and immune barriers that are thought to slow down / reduce the risk of allergic responses, but it also helps maintain gut barrier function. When not enough bile enters the intestine, this can in itself lead to increased intestinal permeability which may trigger unwanted immune reactions (1, 2, 3).

That said, bile production is just one of the hundreds of thousands of mechanical and biochemical pathways involved in digestion and gut function.

Your key takeaway?

Remember that ALL essential nutrients are needed (directly or indirectly) to maintain optimal digestion and optimal gut-barrier function, in turn reducing the risk of unwanted intolerances, sensitivities and allergic reactions.

In other words, a nutrient deficiency will always compromise optimal digestion and optimal gut-barrier function.

And whenever there's failure to digest a foodstuff and large molecules aren't reduced into smaller molecules by the multiple processes in our gastrointestinal tract (whether that process involves bile and/or any other key pathway), it can give rise to intolerances and sensitivities with their typical symptoms: bloating, inflammation, discomfort, constipation/diarrhea, etc. and even set off an immune response trying to fight these macromolecules that were absorbed in the bloodstream and/or compromised the gut lining.

Learn more about this!

If you haven't already, I highly recommend taking the 4-step Gut Restoration Program for an in-depth dive on this (which also gives you extra CPD hours) - click here to see what's inside this Continuing Education training should you decide to take it.

And if you want to help clients with unwanted gut symptoms and add this ad-hoc service to your nutrition practice, be sure to check out our Advanced Gut Restoration Nutritional Advisor certification here.

AUTHOR: Written by Alex Ruani, Research Director

Updated on: 27/10/2026