Commonly used as substitutes for dairy, soy products are becoming more and more popular. However, in some people, soy can lead to diarrhea and other gastric symptoms. If you develop diarrhea shortly after ingesting soy products, you most likely have an intolerance or allergy to soy. Food intolerances are more common than allergies, and can only be diagnosed by your doctor. Food intolerances and allergies are typically confused because they both have similar symptoms. If you experience diarrhea every time you ingest soy, eliminate it from your diet until you are seen by your physician.
In general, a bout of diarrhea typically can last for a few days up to two weeks, according to MedlinePlus. Diarrhea is normal and is commonly caused by a viral infection, food poisoning or traveler's diarrhea. Diarrhea from a soy allergy or intolerance should not last for more than one day. Once the soy is eliminated from your digestive tract, symptoms should subside. Talk with your doctor if the diarrhea continues for more than a day.
Food intolerances are considered common in the United States, according to the American College of Gastroenterology. If you have a soy intolerance, your intestines fail to produce of the proper enzymes to properly digest the proteins or sugars found in the soy. This causes the intestines to become irritated, inflamed and swollen. The body will attempt to rid itself of the soy as fast as possible. You may experience vomiting, nausea or diarrhea within 20 minutes after ingesting soy.
Soy is derived from soybeans, which are considered a legume. Soybeans are in the same family as lentils, peanuts and most beans, according to the Cleveland Clinic. If you have an allergy to other legumes, you are at a greater risk of being allergic to soy. A soy allergy is different from intolerance because it involves more than just the digestive tract. The immune system malfunctions and begins to attack the proteins found in soy, causing a chemical chain-reaction throughout the body.
If the diarrhea is accompanied by other symptoms, it is a sign of an allergic reaction. Common soy allergy symptoms include: hives, nasal congestion, eczema, skin rashes, difficulty breathing, shortness of breath, wheezing, coughing and a runny nose, according to the Cleveland Clinic.com. Severe allergic reactions can be life-threatening. If you develop swelling in your face, throat or lips, dizziness and hives, call 911 immediately.
If consuming soy products causes diarrhea, the best treatment is to stop and avoid ingesting soy. Minor allergy symptoms may be treated with antihistamines and steroid-based creams. Soy intolerance can be treated with prescribed medications, but is mostly treated with an elimination diet. You can substitute many soy products with rice or potato-based products.