Food allergies can cause constipation

Food allergy can indeed induce constipation, and it is the "hidden culprit" that many patients with long-term stubborn constipation fail to find despite seeking medical treatment.

I had contact with a 3-year-old patient in the past two years. He had been constipated for almost half a year. He used half a box of Kaiselu. He changed seven or eight kinds of probiotics available on the market. He also tried various laxative supplements such as prune puree, dragon fruit, and kiwi. The baby hid when he saw it. It still took him three or four days to poop out "sheep poop eggs" one by one. Every time he pooped, he cried and sweated. I went to the hospital several times before and they all said that the child had a delicate stomach and insufficient dietary fiber. It was not until I did a food-related investigation later that I discovered that it was a delayed allergy to ordinary milk protein. Within two weeks of switching to deeply hydrolyzed milk powder, the child returned to soft stools once a day. The parents reported the good news to me with photos of the child's bowel movements, with a tearful tone.

Speaking of this, some people may be confused: I usually get rashes, itchy throat, or diarrhea due to allergies. How come I am constipated?

To put it bluntly, the "competition methods" of allergic reactions are just different. When you eat "allergenic foods" recognized by your body, your immune system will release inflammatory factors to drive away the "invaders". If it is an IgE-mediated immediate allergy, the reaction will come quickly and the symptoms will be severe. Most of them are familiar rashes, asthma, and acute diarrhea. But there is also a non-IgE-mediated delayed allergy. The inflammation will only be secretly stuffy in the intestinal mucosa. It will not be known to everyone, but it will be like applying a layer of glue to the intestines, slowing down the peristalsis speed. If the stool stays in the intestines for more than ten hours, the water will be absorbed by an extra layer. Over time, it will naturally become hard and hard to pass. Many people will not even associate the constipation that appears after several days with a certain food they have eaten before.

Regarding this point, there are actually different voices in the academic community. Most scholars in the field of traditional allergy believe that only rapid IgE-mediated reactions can be considered "food allergy" in the strict sense. Such reactions rarely have constipation as a single manifestation, so in the past few doctors linked intractable constipation to allergies. However, in recent years, relevant research in gastroenterology and functional medicine has shown that the most common symptom of delayed reactions, which accounts for a higher proportion of food allergies, is digestive tract abnormalities, of which constipation can account for nearly 30%. This correlation is even higher, especially among children and young people with intestinal sensitivity.

I also met a 28-year-old female patient who had been constipated for 3 years. At the most severe stage, she could only defecate once a week. Her belly was as bloated as if she had been pregnant for 3 months. She tried various methods such as Internet-famous enzymes, Japanese powder pills, and enemas. The more she used her intestines, the more "lazy" she became. Later, she accidentally discovered that every time she drank the popular oat milk, her bowel movements became... The bloating condition will become more serious. After taking an IgG food intolerance test, it was discovered that she has a moderate intolerance to oats and wheat. She stopped all daily bread, pasta, and oat milk, and took a mucosal repair agent for two weeks. Now she can defecate naturally in basically two or three days, and no longer has to hold the cork out of the door.

Many people have asked me how to tell if their constipation is caused by food allergies? In fact, the most reliable method is not to draw blood to check various indicators, but to "food avoidance + provocation test": first temporarily stop the most common allergens such as milk, eggs, wheat, nuts, and seafood for 2-4 weeks, and observe whether the constipation is significantly relieved. If there is improvement, then add the same food back to the diet separately. If constipation recurs after adding a certain food, the "culprit" will basically be identified. Of course, it should be mentioned here that many specialists do not recommend blind long-term food avoidance, especially for growing and developing children, who are prone to incomplete nutritional intake. It is best to do it under the guidance of professionals and not to avoid food blindly on your own.

Of course, not all constipation is caused by food allergies. If you usually sit for a long time every day, drink milk tea and cola instead of water, and eat vegetables less than three times a week, then your constipation is purely caused by your living habits. You need to change these bad habits first. Only those with stubborn constipation who have tried all conventional laxative methods to no avail and have ruled out organic intestinal disease are worthy of investigation for food allergy. Among the patients I have come into contact with, almost 1 in 5 can be significantly improved after adjusting their diet. It is quite emotional to say that many people have suffered for several years, but in fact they just ate a few wrong things.