FAQ: Are Food Intolerances Real?

Are food intolerances a real thing, or is it all in your head?

This is a question that most of us have asked ourselves at one time or another. Am I crazy, or does (fill in the blank food) really cause me (fill in the blank symptoms)?

You’re not alone, and you’re not crazy. This is a really common and sometimes controversial question, but it’s a really important one too.

Over the past few years I’ve often struggled with the idea of food intolerances myself. “Am I really intolerant to this, or am I just being a hypochondriac?” It took lots of research and experimenting before I came to terms with how intolerances fit into my life (you can read more about my IBS story here.)

In this post I’m taking a deep dive into what food intolerances really are and what the science says (and doesn’t say.) I’m answering aaalll the FAQs, so buckle up! Here are the topics we’re covering:

• Are food intolerances a real thing?
• What’s the difference between an allergy and an intolerance?
• What are the most common food intolerances?
• Why are food intolerances so much more common now than 10 or 20 years ago?
• How do I know if I have a food intolerance?
• If a certain food causes me gas or indigestion, does that mean I’m intolerant?
• How do I tackle my food intolerance?

Are food intolerances a real thing?

Yes. They do exist. Researchers do acknowledge the term “food intolerance”, and more studies on the topic are emerging every year. The older school of thought was that intolerances did NOT exist- it was either an allergy or nothing. But this is an outdated assumption that has been contradicted by the more recent evidence.

What’s the difference between an allergy and an intolerance?

An allergy is when your immune system reacts strongly to a specific food by producing general respiratory, skin, gastrointestinal, or cardiovascular symptoms that can be life-threatening.

An intolerance is a reaction to a food that is NOT related to your immune system and is not life-threatening. Which means that your body isn’t “rejecting” the food, but just can’t properly digest and absorb it. The symptoms, such as gastrointestinal distress and fatigue, can be very different depending on the person and the food. This makes food intolerances harder to diagnose than allergic reactions, and there isn’t one standard test for intolerances like there is for allergies.

Research hasn’t yet explained the “why” and “how” of all food intolerances, but enzyme defects or an altered microbiome are some of the hypotheses so far.

What are the most common food intolerances?

Lactose intolerance:

• An inability to digest lactose (a carbohydrate in dairy products) due to a deficiency in the enzyme lactase
• Common symptoms: abdominal pain, diarrhea, gas, bloating

Gluten intolerance:

• Also called “Non-Celiac Gluten Sensitivity”
• A condition in which gluten can cause symptoms similar to those seen in Celiac Disease, in people who DON’T have Celiac Disease
• Common symptoms: bloating, abdominal pain, diarrhea, constipation, fatigue
• The mechanism is mostly unknown, but it’s thought to impact up to 6% of the US population in varying degrees

FODMAP intolerance:

• A sensitivity to certain carbohydrates (fermentable oligosaccharides, disaccharides, and monosaccharides, and polyols) that aren’t well digested and absorbed
• Associated with IBS
• Common symptoms: abdominal pain, bloating, altered bowel habits

Histamine intolerance:

• An enzyme deficiency that leads to a buildup of histamines in the body, which can cause sensitivity to high-histamine foods
• Histamines are compounds that function in your immune response (like seasonal allergies or itching after a mosquito bite), but are also naturally found in many foods such as chocolate and bananas
• Common symptoms: diarrhea, headache, asthma, flushing, and others

There are other, more rare, intolerances that include fructose intolerance, intolerance to food additives (like MSG or sulphites), specific proteins (like casein), and foods (such as caffeine) that cause negative reactions in some people. And because this is such an emerging topic, there almost certainly are other intolerances too!

Why are food intolerances so much more common now than 10 or 20 years ago?

It’s hard to know whether it’s the chicken or the egg. Are intolerances really more common now, or are we just paying more attention to them? This is a very subjective question with a subjective answer. In my personal opinion it’s a combination of both:

Yes, we’re paying more attention to food intolerances. They’re a “thing”, maybe even a bit of a fad, and the food industry is tuned in.

But, thanks to our modern lifestyle I also think that reactions to food really are more common. Research has shown that our all-too-processed “Western” diet and our busy, stressful lives impact our gut health. Which makes me think that as our diet and lifestyle have evolved over generations, so has our ability to tolerate certain foods.

How do I know if I have a food intolerance?

If you have a food intolerance you will most likely notice:

• Specific symptoms (like any of those mentioned above) after eating a specific food
• Symptoms that are consistent and reproducible: every time you eat that food you experience the same or similar symptoms
• Improvement of your symptoms after eliminating ONLY that food

The challenge with food intolerances is that symptoms can set in at almost any time- from minutes to days after eating. And symptoms can last for short or long periods of time as well. This is why a food/symptom journal is a great troubleshooting tool!

If a certain food causes me gas or indigestion, does that mean I’m intolerant?

Generally, no.

There are a wide range of “normal” post-meal symptoms. For example if you ate a large or high-fat meal, it wouldn’t be surprising if you experienced mild acid reflux. Or if you ate onions, beans, Brussels sprouts, or broccoli you can expect some degree of gas or bloating due to the compounds in these gas-forming foods. You can read more about “normal” digestion in this post.

How do I tackle my food intolerance?

If you have identified a food intolerance or THINK you have a food intolerance, the first place to start is to eliminate that food. But that’s not always the whole solution. Here are some other suggestions for how to approach a food intolerance:

1. Talk to your doctor about it. It’s important to be informed about all your options to make a comprehensive treatment plan. Don’t be shy about advocating for yourself- you deserve to get ALL your questions answered!
2. If you are eliminating multiple foods or entire food groups, work with a dietitian to make sure you’re not missing out on any important nutrients. An overly restrictive diet can be harmful (and stressful!), so guidance from an expert on tailoring your food for YOU can be really helpful.
3. Do your research. Search reputable websites and talk to other people who have the same issue. Take a look at your lifestyle as a whole, there are lots of other factors that influence your gut health other than food (like stress, alcohol, sleep, and exercise, among others).
4. Own it. Self-conscious about being “that” gluten-free person? Stop worrying! Find foods that make you feel good. Focus on what you CAN eat rather than what you CAN’T. There’s no need to feel embarrassed or apologetic about your intolerance, and you don’t owe anybody else any explanations. You do you!

I hope this information is helpful! Check out a few of my other posts on prebiotics, alcohol and gut health, IBS, or normal digestive function for more gut health answers!

See my disclaimer here.

References

Afify et al. Adverse reactions to food: the female dominance-a secondary publication and update. World Allergy Organ J. 2017; 10(1): 43. Available here.

Altobelli et al. Low-FODMAP diet improves Irritable Bowel Syndrome symptoms: a meta-analysis. Nutrients. 2017; 9(9): 940. Available here.

Deng et al. Lactose intolerance in adults: biological mechanism and dietary management. Nutrients. 2015; 7(9): 8020-8035. Available here.

Igbinedion et al. Non-celiac gluten sensitivity: all wheat attack is not celiac. World J Gastroenterol. 2017; 23(40): 7201-7210. Available here.

Maintz et al. Histamine and histamine intolerance. Am J Clin Nutr. 2007; 85(5): 1185-96. Available here.