An upset digestive system after eating walnuts is not common and may be a sign of a more serious condition. Walnuts are a tree nut, which is considered a highly allergic food that can cause various digestive complications. Other common reasons for an upset stomach from eating walnuts are food intolerance, diverticulitis and food poisoning. If you experience digestive upset after eating walnuts, avoid them until you can be seen by your physician.
Tree Nut Allergy
Tree nuts, such as walnuts, are one of the most common foods that can trigger a severe allergic reaction. If you’ve been diagnosed with another nut allergy, you may have an allergic reaction when you eat walnuts. An allergic reaction to walnuts occurs when your immune system mistakes the proteins in the walnut as a dangerous substance. Your body reacts to the proteins the same way it would to an infectious organism by attacking the proteins with antibodies. The allergy-oriented antibodies trigger white blood cells to produce histamine in soft tissues in the digestive system, leading to diarrhea, vomiting, nausea, stomach pain and cramping, according to Kids Health.
Nut Intolerance
Food intolerances are more common than food allergies and cause digestive symptoms within 30 minutes of eating certain foods. Walnut intolerance is the result of your digestive system not being able to properly digest the proteins or carbohydrates found in the nut. The undigested portion of the walnut goes throughout your small intestines and enters the colon. Once in the colon, harmless bacteria interact with the undigested particles, causing excessive gas, bloating and diarrhea, according to the American College of Gastroenterology. Nut intolerance is incurable aside from preventing symptoms from eliminating walnuts from your diet.
Diverticulitis
If you have diverticulitis, eating walnuts may cause pain and cramping in your lower abdomen. Diverticulitis is an infection that occurs in between the bulges of the large intestines. The National Digestive Diseases Information Clearinghouse states that about 10 percent of Americans older than the age of 40 have diverticulitis and about 50 percent of people older than the age of 60 have this condition. Aside from walnuts, you should also avoid eating popcorn, sesame seeds and sunflower seeds until your symptoms subside from this condition.
Food Poisoning
If you eat walnuts that are infected with infectious organisms, you will develop severe abdominal pain, nausea, vomiting and diarrhea. Food poisoning will cause symptoms to develop within four to 36 hours after eating the contaminated nuts. Food poisoning is incurable and is typically treated with rest, more fluid intake and dietary modifications.
