All Episodes

September 8, 2025 14 mins

Do you really have a food allergy or is it just an intolerance? In this conversation with Will Bulsiewicz, you’ll learn the crucial difference between food allergies, FODMAP intolerances, and histamine sensitivity, and why misdiagnosing yourself can lead to unnecessary restrictions and fear.

Dr. Wil Bulsiewicz


Listen to the full episode⁠ ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠here⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠.


Watch the full episode on YouTube ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠here⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠.⁠⁠⁠


***


This episode is sponsored by Spatone – the No.1 iron-rich water supplement.


This is a product I genuinely believe in — one I’ve used personally and recommended in the clinic for years. Spatone is a natural iron-rich water that’s incredibly gentle on the stomach. No harsh tablets, no digestive upset — just one naturally sourced ingredient that works.


If you’re looking for iron support that actually feels good to take, this is the one I trust. You can pick up Spatone at Boots: ⁠⁠⁠⁠⁠⁠⁠⁠Spatone Apple Daily Iron Shots + Vitamin C 28 Sachets - Boots⁠⁠⁠⁠⁠⁠⁠⁠


**


This episode is also sponsored by London Nootropics, the best-in-class adaptogenic coffee I trust. Made with Hifas da Terra mushroom extracts, it supports focus, calm, and energy, and helps you stay sharp throughout the day.

Enjoy 20% off with code LIVEWELLBEWELL at ⁠⁠⁠⁠⁠⁠⁠⁠londonnootropics.com⁠⁠⁠⁠⁠⁠⁠⁠


***


If you enjoyed this episode you might also like:

No.1 Gut Scientist: Insane Fiber Benefits to HEAL YOUR GUT & Beat Disease | Dr Will Bulsiewiczhttps://www.youtube.com/watch?v=8X3b4Hzq75k


***


Sign up to Sarah’s Compassionate Cure newsletter: 

Science Simplified, Health Humanised. Join thousands in exploring actionable insights that prioritise compassion, clarity, and real-life impact. ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠https://sarahmacklin.substack.com/⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠


***


Let’s be friends!

📷 Instagram:⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠  / sarahannmacklin⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠

📹 Subscribe:⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠   / @livewellbewellsarah  ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠

🐦 Twitter:⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠  / sarahannmacklin  ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠

📱 TikTok:⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠  / sarahannnutrition  ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠

💌 Newsletter: https://bit.ly/3rUbHyS

#FoodAllergy #FoodIntolerance #GutHealth

Mark as Played
Transcript

Episode Transcript

Available transcripts are automatically generated. Complete accuracy is not guaranteed.
(00:00):
Welcome to Live Well Be Well, a show to help high performers
improve their health and well-being.
I'm sure you talk about this andsee this a lot in patients that
come to you, but it's food intolerances, which is different
to a food allergy. And A food allergy is is more
severe and, and it happens very,very quickly.

(00:22):
But a lot of people can suffer with food intolerances.
How can we identify them? So I think that you
appropriately started with the first question, which is, is it
a food allergy or a food intolerance?
We have to make that distinction.
It's an important distinction. A food allergy, allergy in
general means that your immune system is being activated in
response to something that is foreign to your body.

(00:44):
So that could be a, that could be seasonal allergies or
exposure to pet dander, or in this case it's exposure to a
specific food. Now there are these classic
foods that are known to trigger food allergies and we think that
they account for over 90% of food allergies out there.
So, and this includes fish, shellfish, eggs, dairy, wheat or

(01:06):
gluten containing products, soy,corn.
I may have forgot one, I think Ithink that covers either.
All of them are very close. Sesame was recently added to the
list as well. I commend you for disremembering
one of those. But the the key here though is
that when you consume this food in any amount, it could be the

(01:28):
smallest amount, it could be thetip of the tongue touching a
little bit, it will activate your immune system and initiate
a violent reaction. And that reaction can manifest
with digestive symptoms, but typically will also manifest
with systemic symptoms, meaning throughout your entire body,
which could be hives, skin changes, swelling, the stuff

(01:49):
that we scared get scared of as doctors, as if you get swelling
of the lips or of the throat because that could negatively
affect your ability to breathe. Do you?
Want to know what mine is, Will?Yeah.
It's the worst allergy of all time.
It's grapefruit. Grapefruit.
Do you get it? Is it an oil allergy?
Yeah, I, I it's my tongue explodes.
I get lumps and welts all over my body like I restrict some

(02:10):
breathing. Other citrus you do OK.
Yeah, citrus is fine, but I'm just giving the love out there
to grapefruit to anyone else that's got that allergy I feel.
You. Wow, Wow.
Yes, OK. I think that the key here is
that you've just exemplified though, because if you, if you,
if you touch, if, if you put grapefruit to your lips on any

(02:31):
level, you don't even have to like literally put a piece into
your mouth. You could literally just put
your lips on the grapefruit. It would probably trigger that
reaction. And that's a scary reaction.
That happened last week. I was put in a cocktail just a
tiny little bit and I barely touched it and my night was over
within. Oh dear.
So that's an allergy. Yeah, that's an allergy and

(02:53):
that's an that's the activation of the immune system and A food
intolerance is different. So we have to rule out food
allergy 1st. And then what is left is a food
intolerance is when you consume a food in normal amounts.
Like, you know, if we drink a gallon of milk, we're going to
get sick. We're all going to get sick if

(03:14):
we drink a gallon of milk, right?
But that's not a normal amount of a food intolerance is when
you consume a food in normal amounts and it triggers
symptoms. And the reason why is because
this is not activation of your immune system in response to a
foreign thing. This is your body struggling to
process and digest the food. And so it's sloppy digestion.

(03:39):
The classic food intolerance is lactose intolerance.
If we expand our view, there's sort of two main categories of
food intolerances that I think about.
These are the classics, and they're unique and different.
The 1st is in response to carbohydrates.
These are Fodmaps, so FODMAP. This is an acronym that stands

(04:03):
for fermentable Oligosaccharides, Disaccharides,
Monosaccharides, and Polyols. It's a mouthful.
So please, you said that, not me.
Yeah, it includes fructose, which is a sugar that you will
find in many in many fruits. It includes lactose from dairy
products, fructans which are more complicated, almost like

(04:27):
fiber, and you will find them ingarlic, onions and gluten
containing foods. So like wheat, barley and rye.
So in a number of different foods, you can find these
fructans and then galactans, which you'll find in legumes.
And finally, the polyols are, are the sugar alcohols that you
may find in fruit, but you may also find in artificial

(04:50):
sweeteners that you add to, you know, your coffee or something
like that or your tea. This group, this big group of
Fodmaps, this is 1 type of food intolerance.
And it's interesting because like there are these people who
think that they have gluten intolerance.
And we could dig into the evidence if you want to, Sarah,
but many of these people, if they don't have celiac disease,

(05:12):
actually they're not responding to the gluten.
They're responding to the fructan, which is found in the
wheat or the barley or the rye. And so food intolerance or the
other type of food intolerance is histamine intolerance, which
is not quite as common as FODMAPintolerance.
But histamine intolerance is basically where you have a

(05:33):
damaged gut and because you havea damaged gut, your body is
struggling to process and digesthigh histamine foods.
And this could include like the classic high histamine foods are
like fish, shellfish, fermented foods, and then among the plant
based foods, spinach, tomatoes, avocados and eggplant.

(05:54):
Those are the classic high histamine foods.
The key with these is that your body can be trained to consume
these foods. And if you were to take these
foods that you have an intolerance to and reduce and
moderate the amount that you consume at one time, you'll be

(06:16):
fine. So if you simply reduce the
amount you can consume these foods that you struggle with and
by reducing that amount, you actually start to get better at
consuming these foods. And so it's conceptually similar
to exercise. No one walks into the gym on the
first day and lifts the heaviestweights.
The people who are lifting heavyweights, it's because they've

(06:37):
been building up to that for many years.
Each of us has a certain capacity for work that we're
capable of. And so when we go to the gym,
you should work out within the the bounds of what your body is
capable of doing without crossing that line.
And when you do this, the line starts to move and over time

(06:59):
you're able to do more. And that's the concept of
exercise. And that's the same concept that
we should apply to overcoming food intolerances.
Exercise your gut and you will make it stronger. 1 billion
people worldwide are deficient in this nutrient that so many of
you guys might not be aware of. And women, if you're listening,
you are more at risk of being deficient in this nutrient.

(07:21):
So I'm going to first of all explain what the physical
symptoms are. If you have cold hands and feet,
pale skin, extreme lack of energy or fatigue then you might
be suffering with iron deficiency or anemia.
Now First off, please go to yourGP to get your iron levels
checked. Secondly, please explore a good

(07:41):
iron supplement. Many people that come to me are
worried about taking iron supplementation because it can
cause Constipation or GI distress.
That's why I'm so incredibly proud to be partnering for this
episode with Spartan, the numberone iron rich water supplement.
Now, I've personally been using these for years.

(08:01):
The reason why is because they are naturally sourced, highly
absorbable iron. That means it's much more gentle
on your stomach. There's no harsh tablets.
It's just one naturally sourced ingredient that works very well.
You can pick it up in Boots or buy online at Amazon.
But please do not ignore this. It is really critical to make

(08:23):
sure your iron levels are in check.
I love that you conceptualize this into two different parts.
And I think a lot of people may have heard and, or definitely
our listeners would have heard the Fodmaps in relation to
obviously Monash University. And we actually then come on and
talk about how they created the FODMAP diet and heavily linked
to IBS and, and that was, you know, fascinating.
And obviously, as you said, it's, it's not something that

(08:46):
you can never have. The whole part of the FODMAP
diet is that it's meant to be a short term strategy and then
you're meant to reintroduce these foods.
Whereas sadly, when it's done incorrectly, a lot of people get
like an incredible amount of fear from these foods because
they're terrified of reintroducing them.
And that's when, you know, actually a lot of countries all
that eating can happen. But then you also mentioned
another one, which is a chapter in your book, by the way.

(09:08):
It's a whole chapter on histamine.
It's fascinating because my brother actually the other day
doesn't really have any food allergies, any intolerances, and
I'm sure he won't Remember Me saying this.
It was about 6 months ago. And his whole body just all of a
sudden reacted. I mean, his tongue was stirred
up. And I mean, when you were talk
talking about like an allergy, this was the response and we
were trying to figure out what it was.

(09:30):
And when he went to A&E, the doctor said what have you eaten?
And he was like, what I eat everyday, salmon, beans, like
normal things, but he'd left thesalmon in the fridge for so
long. Typical man hadn't like put it
in any protective packaging. And the histamine had risen so
high that it caused a really bigkind of histamine reaction.

(09:52):
Can you talk a little bit more about how can we detect like
which route are we going down? So if someone's listening to
this and say, OK, well, I've gota food allergy and I don't
really know where to start. Maybe I have a histamine allergy
or maybe I go down kind of the FODMAP side.
How can people navigate this area a lot more and and a lot
more clearly? Great question.
Your brother, what he we had specifically we call scumbroid

(10:14):
poisoning and so, and it's not necessarily indicative of a
chronic histamine intolerance. So it's the reason why I'm
bringing it up is there's a bit of a distinction to me, a
chronic histamine intolerance isthat when you routinely consume
foods that are higher in histamine, you manifest
symptoms. Whereas in his case, it was a

(10:35):
one time deal where he consumed this bad fish.
And it's a classic thing. And it's the the bad fish
because it's been, it's basically hasn't been cooked and
it's been sitting out for too long, has turned into a super
high histamine food. And even with a healthy person,
it would overwhelm them and theyget this form of food poisoning.

(10:56):
All right, how do we, how do we approach this issue?
So let's pretend for a moment ifit's OK.
I would like to break this into 3 possibilities.
The three possibilities are a food allergy, FODMAP intolerance
or histamine intolerance. OK, now food allergy is going to

(11:17):
be a manifestation of systemic effects.
It could be gas and bloating. It could also be skin changes,
swelling, things like this Lightheadedness.
All right, to one specific food or to one class of foods, right.
So it could be dairy products and every single dairy product

(11:41):
food, if you consume it, you getthis reaction right with you.
The one food is grapefruit, right?
It's no other food. It's just grapefruit.
And the thing about a food allergy is that it's a response
of your immune system to one of the proteins.
It's always a protein. So if you have a food allergy,

(12:04):
it's going to always, it's goingto be consistent, it can be any
amount, could be small or large,and it's going to be these
systemic effects. All right #2 in terms of
possibilities is a FODMAP intolerance.
Now, a FODMAP intolerance is going to be to these classes of
foods. So it could be fructose or

(12:28):
lactose, which is in dairy products or fructans, again in
wheat, barley, rye, garlic, onions or galactans from
legumes. And it's not as necessarily
consistent as the food allergy would be.
It also is going to manifest with digestive specific symptoms
when it's a FODMAP issue, right?So it's like these are people

(12:51):
that get gas, bloating, discomfort, diarrhea or
Constipation classically occurring in people that have
irral bowel syndrome or some other digestive health problem
like ulcerative colitis or Crohn's disease.
All right, So these are the people that will manifest one of
these types of intolerances. And again, like if you thought

(13:12):
of these as categories, now thistypically involves working with
a registered dietitian. But if you were to work with a
registered dietitian and basically test within these
categories, you would find that it's not just grapefruit, it's
this class of, of fructose containing foods that's causing

(13:33):
the issues. So any food that contains
fructose can be potentially problematic.
All right, So it's a class effect and you're not going to
get the tongue swelling or the hives or things like this.
All right. The third one, less common, a
little bit more tricky is the histamine intolerance, because

(13:54):
the histamine intolerance, yes, it will manifest with digestive
symptoms like bloating. That's sort of the classic
symptom, but most of the time with histamine intolerance, it's
also going to manifest with other symptoms throughout your
entire body. Could be headache, could be
migraine. A low histamine diet has been

(14:14):
shown in clinical trials to be beneficial to people that have
migraine headaches. This is like the origin of this
concept. Thanks so much for listening to
hear the full episode. There's a link in the
description.
Advertise With Us

Popular Podcasts

Stuff You Should Know
Dateline NBC

Dateline NBC

Current and classic episodes, featuring compelling true-crime mysteries, powerful documentaries and in-depth investigations. Follow now to get the latest episodes of Dateline NBC completely free, or subscribe to Dateline Premium for ad-free listening and exclusive bonus content: DatelinePremium.com

The Breakfast Club

The Breakfast Club

The World's Most Dangerous Morning Show, The Breakfast Club, With DJ Envy, Jess Hilarious, And Charlamagne Tha God!

Music, radio and podcasts, all free. Listen online or download the iHeart App.

Connect

© 2025 iHeartMedia, Inc.