Can Pasta Trigger Irritable Bowel Syndrome?

If you find yourself sprinting to the bathroom the morning after feasting on a big bowl of spaghetti, you might wonder, "Why does pasta give me diarrhea?" Pasta seems like a pretty safe, easy-to-digest food, right? And for some, it is — but for others, it may bring on irritable bowel symptoms.

Irritable bowel syndrome (IBS) is a common disorder that affects the way your digestive system functions, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Symptoms may include constipation, diarrhea, abdominal pain, bloating and an urgent need to defecate.

The good news is that IBS doesn't appear to damage your digestive system, NIDDK says. But, IBS is definitely an inconvenience that can reduce your quality of life sometimes. While the exact cause of IBS is unknown, there are certain things that seem to play a role in IBS, and diet is one of them.

​Read more:​ 11 Foods to Avoid When You Have IBS

"When it comes to tolerance of pasta, it varies from person to person," says Kelly Krikhely, RD, CDN, a clinical nutrition coordinator at Mount Sinai Hospital in New York City. "Some people with IBS may tolerate pasta just fine, but certain susceptible individuals can develop symptoms [after eating pasta]."

Does that mean that linguine and fettucine and mac 'n' cheese are forever banned from your plate? Probably not.

"Often, for those who may experience symptoms after having pasta, it can also depend on the amount consumed," Krikhely says. "Eaten in smaller portions, like a half-cup cooked, it may be tolerated, while larger servings may lead to gastrointestinal discomfort."

What you put on the pasta matters, too, she says. A few examples of pasta toppings that might cause problems include garlic, mushrooms, cauliflower, sundried tomatoes, ricotta cheese and artichokes.

"Any one of these toppings could potentially trigger symptoms in an individual with IBS," Krikhely says. "The key is identifying which of these items, if any, may be causing symptoms."

The good news in this? Once you've identified the problem foods, you can probably enjoy the rest without triggering your symptoms.

"Diet plays a major role when it comes to irritable bowel syndrome," Krikhely says. "Often, those with IBS have food intolerances, and identification of those intolerances can assist with symptom management."

Foods containing FODMAPs are often the culprit in IBS, Krikhely says. FODMAPS stands for "fermentable oligosaccharides, disaccharides, monosaccharides and polyols," a group of fermentable carbohydrates found in some foods.

Foods you should eat less of if you're trying to eat a low-FODMAP diet, according to Harvard Medical School, include:

• Dairy foods containing lactose.
• Some fruits, including apples, pears, peaches, cherries, mangoes and watermelon.
• Foods made with high-fructose corn syrup.
• Certain grains, like wheat and rye.
• Some vegetables, including artichokes, asparagus, broccoli, Brussels sprouts, mushrooms, snow peas, garlic and onions.
• Some beans, such as chickpeas, lentils, kidney beans and soy.
  

When people with IBS eat foods with FODMAPs, they may not be well digested or absorbed, Krikhely says. That can lead to IBS symptoms like gas, bloating or diarrhea.

"Which foods — if any — are not tolerated is very individualized and often dose dependent," she says. "Individuals with IBS may be able tolerate certain foods in smaller doses, but when consumed in larger quantities, these foods may trigger symptoms."

The low-FODMAP diet is effective in figuring out which foods are a problem. But, because this diet is so restrictive, Krikhely says it should be undertaken in three phases. The first is a period of elimination. That means all high-FODMAP foods have to go. Foods are then gradually reintroduced to see which you don't tolerate well. And, eventually, all the foods you can tolerate well are reintegrated back into your diet.

"It is a short-term diet that may help certain individuals with IBS identify which foods they may need to avoid," she says. And, because it's a complex diet plan, it's a good idea to work with a dietitian when you attempt it.

​Read more:​ How the Low-FODMAP Diet for IBS Works, and How to Get Started