Stomach cramps, bloating, abdominal discomfort and pain are common features of IBS, or irritable bowel syndrome, but several other gastrointestinal disorders also can be the culprit. If you have noticed that you have cramps every time you eat onions or carb-rich foods, there might be a connection. Keep a food diary to record everything you eat and your symptoms to help you confirm this association.
Onions can be hard to digest, especially if eaten raw. If cooked onions of all kinds, including brown onions, white onions, Spanish onions, green onions and shallots, all produce similar symptoms, you might be reacting to the fructans they contain. Fructans are a chain of fructose molecules that some people do not tolerate very well, especially if you have fructose malabsorption. People who do not tolerate fructans well can even experience gastrointestinal problems after consuming a dish containing small amounts of onion salt, onion powder or a broth made with onions. If onions induce severe stomach cramps, it is very likely that garlic, Brussels sprouts, watermelon and artichoke will cause the same problems.
Some carbs can be problematic for your intestines if you have fructose malabsorption, which corresponds to the inability to properly absorb some short-chain fermentable sugars and is associated with mild to severe stomach cramps, bloating, flatulence, diarrhea and constipation. The most problematic carbs for fructose malabsorption include foods made from wheat, barley and rye; high-fructose fruits such as apples, watermelons, pears, cherries and mangoes; and high-fructose sweeteners such as honey, high-fructose corn syrup and agave nectar. These foods either contain fructose or fructans in amounts that can cause gastrointestinal discomfort.
If you have fructose malabsorption, which is an under-diagnosed and under-recognized gastrointestinal disorder, your body is not able to properly absorb fructose and fructans. As a result, these short-chain sugars become food for the bacteria in your intestines, which produce a lot of gas that causes bloating, pain and cramping. Changes in your bowel movements, such as diarrhea or constipation, are also common symptoms of fructose malabsorption.
To find out if fructose malabsorption is the source of your severe cramps when eating onions and certain carb-containing foods, ask to be referred for a hydrogen breath test. If your test indicates that you are a fructose malabsorber, get a referral to meet with a registered dietitian with experience in gastrointestinal health for help identifying all the potential trigger foods that are responsible for your stomach cramps and other gastrointestinal symptoms.