Food Intolerance and IBS

Many people have a food intolerance or food allergy and don’t even know it. Studies have shown that people can reduce or even eliminate IBS symptoms removing problem foods from their diet!

Food allergy… Food intolerance… Food sensitivity? What’s the difference?

Rubber stamp pictures for food sensitivities. From Solving the IBS Puzzle.Does a food sensitivity have your guts tied up in knots?



An intolerance is not the same as an allergy. A food allergy is an abnormal response by your immune system to something you ate or drank. The good news is that (according to the Mayo Clinic) only about 2% of adults and 6% of children have food allergies. What a lot of people think of as food allergies are really an intolerance, which is FAR more common.

So what is a food intolerance or sensitivity?

A food intolerance doesn’t involve the immune system, but can cause illness when that food is eaten. Some people use a third category called food sensitivity for foods that cause digestive or health problems but are less severe or are hard to trace. Other people use “food intolerance” and “food sensitivity” as different ways to say the same thing.

How does a food intolerance cause problems?

Many people have trouble digesting certain foods. Their bodies might be missing an enzyme, or some other digestive tool to process a certain food. When a food doesn’t break down properly, it can cause all kinds of unpleasant effects, such as diarrhea, gas, constipation, bloating and abdominal pain. Sound familiar?

Does food intolerance cause IBS?

Not exactly. But some people may think they have IBS, when they really have an undiagnosed intolerance to a food. Many people suffer for years with IBS symptoms before finding out the main culprit is a food sensitivity or intolerance. Even if an intolerance isn’t the major cause of your IBS symptoms, sensitivity to a food can trigger IBS symptoms. I found that out the hard way. Here is that story if you’re interested. I gave up some foods that were making me sick, and cut down on some others, and now I feel a LOT better. YOU CAN TOO!

Food sensitivity and intolerance heavy hitters…

Below is a list of foods that many people have problems with. Note that while some people are allergic to some of these items, this isn’t a food allergy list.

Foods items

  • Dairy products – Made for baby cows. Why do we drink it anyway?
  • Wheat and/or gluten – This is a kind of grass. Hay fever anyone? Chocolate – Sorry to say it.
  • Fructose – Malabsorption of fructose is linked to diarrhea and depression! Yeast – Found in breads, cheeses, and many other food items, this fungus can cause you problems whether it’s alive or dead.
  • Soy products– Particularly genetically modified soy.

Food Additives

Here is a short list of food additives that many people have problems with:

  • MSG – An excitotoxin. Many people (including some in the medial field) believe that MSG and Aspartame can “excite” neurons and/or nerve cells to death!
  • Aspartame – Another excitotoxin, many people recommend stevia instead. I just avoid sweeteners. I’m sweet enough ;).
  • Artificial colors – British studies also link artificial colors to ADHD symptoms.
  • Olestra – This fat substitute works reduces calories in the body by being INDIGESTIBLE! Abdominal cramps an loose stools are known side effects. Other IBS symptoms are commonly reported.
  • Preservatives – Maybe making things indigestible by bacteria makes them indigestible by humans.
  • Sulfites – Sometimes sulfites are used as a preservative, sometimes they occur naturally (in wine for instance).

An elimination diet can help find YOUR villains.

Man stuck sitting on the toilet. Could he have a food sensitivity? From Solving the IBS Puzzle.



This is a systematic approach of eliminating and adding back foods to see which ones you may have problems with. If you have IBS you should talk to your doctor about trying an elimination diet to see if you have a food allergy or intolerance. He or she may refer you to a nutritionist, to help with the process. See a list of foods you may be intolerant of OR go see a list of low FODMAP foods.


  1. Reply

    hi my son is 3 yr old.. and whenever he eats chocolate cake.. he gets loose motion… I hv noticed this thing 2-3 times.. kids of his age enjoy chocolates and cakes bt I hv to deprive him from all this

  2. Reply

    Yeah I was having bowel issues and went to an ayurveda counselor. Based on my personality and the issues presented she predicted that my body type would not tolerate night shades among other things and this helped a lot! It was less expensive than a naturopath and she gave advice about activities and specific yoga postures to help as well.

  3. Reply

    I always seem to get diarrhea after as little as 1 bottle of larger. I started to notice this about 6 months ago. I’m not 100% sure it’s the alcohol as my diet isn’t the greatest either but the correlation between my diarrhea and specifically “larger” is very high.

    For example, during my time noticing this trend. I went to Dublin with the lads, as you can expect there was plenty of alcohol.
    But I drank almost exclusively Guinness and I don’t remember having any bowel issues at all during that whole weekend.

    Last night I had one bottle or Coors light and this morning I have diarrhea.

    I don’t know anything about the ingredients of either of those drinks really so could anyone enlighten me on what they think might be the cause?

    • Reply

      To Jay:

      In regards to Lager, you could be Gluten intolerant. This would mean you would need to avoid any beer made of wheat, rye or barley. I personally can’t drink any speciality craft beer, but can drink one or two bottles of something that is highly processed like corona light or miller light. Bread itself, if you are in the U.S., isn’t regulated, so sometimes white bread will cause no “problems” while a dark Rye will cause a visit one to two hours later, to the bathroom. Some Italian restaurants cause a reaction, while others don’t.

      I guess I was lucky & had an easy “trigger” that helped me discover my gluten intolerance. I suddenly became lactose intolerant at the age of 35. I gave up bread for a while, and could go back to drinking milk.

      Since then, because of my love of all things bread, I do tend to “try” way too much out there. However, I have come, through careful isolation, aware of what I can eat in small quantities and what to avoid.

      Ok list:
      Sourdough bread
      Buttermilk Biscuits or pancakes
      Olive Garden is ok (but too salty in the area I live in)
      Gluten free soy sauce
      Gluten free beer
      Grain alcohol is ok
      Macaroni Grill is ok
      Soba or buckwheat noodles
      Anything with buckwheat
      Fried chicken, using cornflakes instead of flour
      Oatmeal (since I’m not someone with celiac disease, I don’t have to get expensive wheat free version)

      Avoid list:
      Whole grain bread
      Rye or barley bread
      Soy sauce (most made from wheat)
      Malt (no whoppers or malt shakes😥)
      caramel and caramel flavorings
      Natural beers, lagers, ales, etc.
      2 local Italian restaurants (they are high dollar & high quality, so probably use “natural” pasta’s – thankfully one of them is near a bookstore 😅)
      White gravy on mash potatoes
      Most fried foods
      Most cereals
      Malt o Meal
      Nothing Bundt Cakes(I love all flavors but they don’t love me😏)

      Hope this is useful

  4. Reply

    I have a sugar malabsorbtion problem. Been to many specialist and nobody could figure out what was wrong with me. All tests came back negative. I have been to Mayo Clinic as well. The Dr there ordered a breath test to ck for parasites. All I got from this was a document stating everything was normal. After about the sixth time of “me” going over the results….”I” discovered the breath test had a notation on it saying “patient produces methane vs hydrogen”. The Dr never said anything to me about this :( when I did research….found out that methane producers cannot tolerate sugar. Needless to say I was upset with Mayo Clinic Dr. Since then I have eliminated sugar altogether and this has helped. I can only eat about 15 different foods now but I am slowly healing. I suffer from severe abdominal bloating. I hope this helps someone who is suffering from what I have. I have not found anyone yet on the Internet that has the same problems as myself yer but if there is someone out there I would be glad to hear from you.

    • Reply

      Dear Anita,
      There are other people out there because I am one of them!! I have had “food” problems since I was 10. I began having swelling in my face and head, with severe headaches! They thought I had a brain tumor. But God brought a new young doctor to the area where we lived, and he immediately said “that child is allergic to something she is eating”. Looking back I can see what a blessing that was. I went through the elimination diet, and immediately reacted to milk, chocolate and peanut butter. That was the beginning of my journey for the next 40 years. Leaving those foods out of my diet, still left me with lethargy and migraines quite often. I guess it becomes a way of life, and was tolerable, at least until I turned 36. I began with severe brain fog, muscle weakness and pain, and quite a bit of joint pain. I struggled for several years feeling as though my body was steadily dying. I didnt go to doctors much becuase it was always the same …. test/labs always normal, and they never really seemed to have the time to look beyond what a test result showedl!! ( I am an RN but prefer holistic medicine over traditional medicine) If you have a symptom, traditional doctors will just prescribe a pill! Most medication made me feel even worse. I did learn that whenever I would stop eating, I would feel better. So fasting always helps!! Through ongoing research, I decided to go gluten free. That was a huge improvement for my health. No more migraines, brain fog, or all the symptoms of fibromyalgia! It wasnt a complete improvement but it was significant enough that it was “livable”. Well that is, up until last year. i began having multiple type autoimmune issues, and abdominal bloating. I began increased studyung and research. Over a 5 month period I gave up night shades and started a Low Fodmap diet. it became very obvious that I did not tolerate any of the sugar groups! Wheat and onions absolutely killed me…. severe swelling and inflammation. I do not tolerate sorbital, manitol or even xylitol. As I quit more and more foods, I did begin to feel better. At least the Autoimmune symptons and inflammation significantly decreased, but the bloating seemed to be ongoing. Over the past 4 months I mainly eat low fodmap protein. I was tolerating some meat, hard cheese, eggs, rice, some gluten free bread. I could eat a couple veggies and fruit, but not many!! I still had bloating but not as bad with these foods. But during this time I also started to have severe constipation, and the bloating started to increase even with these few foods. I already new i had an intolerance to sugars, but my research also led me to study SIBO-c (methane gas) and gastroparesis. I dont have all the answers yet but I do know that I dont really get them from tradition doctors. Have had EGD, abdominal CT and Colonoscopy…. all of which were “normal”. I have been to the point were I would rather here tumor, blockage, or anything but “normal”. Since I have pretty much died to food over many years, and I dont know that the food allergy/intolerance (call it whatever you want) will ever go away. I am now focusing on my gut motility to prevent stagnant food that leads to bacterial overgrowth! I know how frustrating this is! Everything revolves around food, and it can definitely interfer with your socialization. I have just accepted that this is my cross to bare. None of the tests or procedures have been a waste of time. Each one is a piece to the puzzle! But God is the great physician and He is my medicine! As I research now, I always include Him in this journey. Physicians may not have our answers but God does. I may only get to eat a few select foods, but I can testify that I am were I am today because of Him! He has given me the ability to find peace in living with it. Maybe one day it will be healed! I pray you have found some answers over the past year and a half. Just know, you are not alone (and I know it can be a lonely journey!)

      God bless you,

  5. Reply

    Hello, I’m currently starving doing the wheat free diet to see if that helps me. How do i maintane a healthy weight and still not starve? how do i know for sure if wheat is to blame?

    • Reply

      Hi Cassie, when I first went off wheat, and some other things, I lost 50 pounds. I had about 30 to lose so I was pretty underweight. I ended up eating more meat and vegetables, along with healthy fats. That helped. I also ate a lot of things I probably shouldn’t since then. There are a lot more “wheat free” options out there. There are lots of recipes for wheat free cooking in the celiac community (which is a kind of wheat intolerance. As far as finding out if wheat is to blame, there is a blood test for specific antibodies that can sometimes tell you. There is also food elimination diet, that can help isolate foods you might be sensitive too.

      For my case, the doctor told me that the antibody test came back negative so wheat shouldn’t be a problem. In reality, when I eat wheat I get sick, if I avoid it, I get sick much less often. That’s proof enough for me. As usual though, you should consult a competent medical person.

  6. Reply

    I used to suffer terribly from IBS, 40 years later, accidently, I found that the cause (for me) was eating any of the Nightshades- Potatoes, Tomatoes, Peppers.. (I so wish that someone had suggested I avoid these foods)
    Of course everyone is different but its worth a try,
    A week avoiding potatoes and Tomatoes fixed me, after half a lifetime spent in the Bathroom-
    Last week I cam across this article as well.
    Hope this helps someone,
    Kind regards,

    • Reply

      AMAZING! I have not seen this information before. Thanks so much for sharing!!! I’m sure it WILL help someone.

      • Reply

        For years I have struggled with IBS symptoms. It gradually got very bad and eventually included occasional fecal incontinence. Never any blood and I otherwise felt healthy and strong, however I had to quit my job and retire.
        During those years I read about many people suffering from this, and I tried lots of things. I kept a food diary but saw no pattern. I thought it had to do with food but no diet worked well enough to be sure.
        Then I eliminated potatoes and rice and for the first time got some dramatic relief. More time passed and after some success and some disappointing relapses my wife suggested nightshades were the culprit.
        This is a tough one because almost all prepared foods contain one or more nightshades. Potato flour or starch is in so many things including most soups and gravy. All my favorite food has peppers. Anything with “spices” might include nightshades. Tomatoes are everywhere. And I had just started to enjoy eggplant.
        Making all my food from scratch and carefully reading labels to avoid all nightshades worked, and after a month I was doing great. Going out to eat is nearly impossible, but many months later I’m feeling pretty normal.
        Turns out rice is not a problem for me, it was the spices (and possibly annatto, not a nightshade but it is associated with IBS).
        Doctors I have seen can’t explain it, and other than a few anecdotal accounts (like Jennifer’s here) I still cannot find evidence that nightshades cause IBS symptoms. Without corroboration it will take much more time for me to feel really confident, but for now things are going very well and I wanted to pass along my experience in case it’s helpful to anyone.

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