Finding the Right Diet for IBS

Finding the Right Diet for IBS

What's the best diet for someone with IBS? Can IBS be controlled with diet alone? Expert Patsy Catsos, MS, RD, answers these and other questions about diet and IBS.

It's not easy to find the right diet when you have irritable bowel syndrome (IBS).  Eating certain foods can cause major discomfort for people with IBS, but figuring out which foods cause the symptoms is a highly individual process.

WebMD consulted gastrointestinal nutrition expert Patsy Catsos, MS, RD, author of IBS -- Free at Last!, for answers to your questions about diet and irritable bowel syndrome. 

What is irritable bowel syndrome and what are the symptoms?

Irritable bowel syndrome (IBS) is often defined as abdominal pain and discomfort with altered bowel habits, in the absence of any other medical explanation for the symptoms. Patients with IBS often report gas, bloating, diarrhea, or constipation.

How can you distinguish normal digestive problems from those needing medical evaluation?

Certain foods, like beans and prunes, can cause gastrointestinal effects in most people.  A certain amount of gas is normal and healthy. The average person produces 1-4 pints a day and passes gas 14 times!  It’s also normal for the consistency and frequency of your bowel movements to vary somewhat. 

However, if you are experiencing abdominal pain, a change in your bowel habits, or if your gas, diarrhea or constipation is interfering with your normal activities, you should see a doctor. It's important for your health care provider to help you rule out other problems, especially if you have any of the following:

  • Blood or pus in stools
  • Family history of colon cancer
  • Celiac disease
  • Fever
  • Malnutrition
  • Symptoms that wake you from sleep
  • Onset after age 50
  • A lump you can feel by touch
  • Unintentional weight loss


Can IBS be controlled by diet alone?

In the diarrhea-prominent type of IBS, the primary form of treatment is diet. Constipation can be more challenging to treat with diet alone. Other forms of noninvasive therapy that are routinely used are physical therapy and stress management, because studies show the mind-gut connection is very real.

Are there certain foods that aggravate the digestive system?

Each person is unique. But in general, foods that are high in fat, fried foods, spicy foods, alcohol, and caffeinated coffee and tea can be problematic. Some foods, such as beans, cabbage, broccoli, Brussels sprouts, cauliflower, peas, onions, and bagels, that can cause minor discomfort in a normal GI tract can cause significant bloating, gas, and abdominal pain in IBS sufferers.

What is the best diet for people with IBS symptoms?

There is no one-size-fits-all diet. A proper diet for IBS is highly individualized.

A high-fiber diet was thought to be the best diet for almost everyone with IBS, but recent studies have shown that this isn’t true for everyone.

For people with constipation, it's common to try a high-fiber diet of 25 grams daily for women and 38 grams for men to see if that helps. People should eat as much dietary fiber as they can tolerate, and understand that a certain amount of gas production is a sign of healthy gut microbes at work.  

The challenge is finding an acceptable fiber intake without experiencing debilitating abdominal pain and bloating, and frantic dashes to the toilet. And sometimes focusing on fiber alone doesn’t address the removal of potential trigger foods from the diet.

What's the best diet approach if you suspect you have IBS?

Eating smaller, more frequent meals spread throughout the day instead of larger meals can lead to less discomfort for some people.  What is really important is to identify the foods that are causing the symptoms. 

For individuals with diarrhea, gas, or bloating, or if a high-fiber diet fails, I suggest a two-week trial FODMAPS elimination diet. (FODMAPS stands for fermentable oligo-, di-, and monosaccharides and polyols.)

What is the FODMAPS approach?

You'll work with your physician and registered dietitian to eliminate all foods that contain the five forms of carbohydrates (lactose, fructose, fructans, sugar alcohols, and galactans) for a trial period of 1-2 weeks.  If FODMAPS carbs are causing the symptoms, relief can occur in just a few days.

You follow the elimination period with a challenge of reintroducing one of the FODMAP carbs and observe symptoms. Additional FODMAP carbs are slowly added back, one at a time.  At the end of the reintroduction phase, a final diet emerges with only those FODMAP carbs that are fairly well tolerated.  

The goal is to find the most liberal and varied diet possible that still keeps symptoms under control. Most people find they can still include their favorite foods if they exercise care. For example, a person who discovers that fructans (found in wheat) cause a lot of distress might find they can’t tolerate wheat at every meal, but may be able to tolerate one portion of wheat without a problem.

Is the FODMAPS approach accepted in the medical community?

Health care providers have known for years about the GI impact of select FODMAPS, such as lactose and sugar alcohols. Fructose and galactan intolerance are a bit newer. Although it is very well accepted and widely practiced in Australia, it is a new idea for most health care providers in the U.S.

The FODMAPS approach is unique because it views all of these carbohydrates as one big system, looking at the forest instead of the trees. Some providers are concerned that the FODMAPS is too complicated, but many patients are very motivated and willing to do anything to feel better.

Is a gluten-free diet a good option for IBS sufferers?

Gluten-free diets are very popular right now for a wide variety of conditions. When you eliminate gluten, you also eliminate wheat products that contain fructans, one of the FODMAPS carbohydrates.

Why are some carbohydrates more problematic than others?

Eating certain carbohydrates can cause gas, bloating, and watery diarrhea for some IBS sufferers. Lactose, or milk sugar, is one example many people are familiar with. If your bowel has difficulty tolerating lactose, when you eat it -- especially in high doses or when you eat it alone -- bacteria in the large intestine ferment it, and it can result in gas and painful bloating as well as excess flatulence.

Can probiotics or digestive enzymes help reduce symptoms?

The use of probiotic supplements may help reduce symptoms in the long run, but I would encourage using a FODMAPS approach before introducing probiotics into the diet.

Lactase is the name of the enzyme that breaks lactose (milk sugar) down to simpler sugars during digestion. Using milk products that have been pre-treated with this enzyme, or taking an enzyme, are good strategies for reducing symptoms. Naturally fermented foods, such as yogurt and kefir and hard cheeses, contain less lactose than milk and may be better tolerated. 

In a nutshell, what are recommended foods for IBS sufferers?

Use lactose-free or reduced-lactose dairy products; small servings of berries and citrus fruits; potatoes, rice, oats and corn products; lean meats, fish and poultry; salad vegetables; and plant-based oils. When it comes to sweeteners, small servings of granulated sugar and maple syrup are usually well-tolerated.

Keep your diet as varied and colorful as you can tolerate. Remember, you can probably tolerate small servings of your favorite high-FODMAPS foods. Even if a whole bowl of grandma’s baked beans is out of the question, a little bite won’t hurt you.

Are people with IBS at risk for nutrient deficiencies?

Some people with IBS eliminate entire food groups to control symptoms. These very limited diets can cause weight loss and at the other extreme, weight gain. Unfortunately, some people with IBS find that the “healthier” they eat, with more fruits, vegetables, whole grains, and milk, the worse they feel. All of these situations can put them at risk for vitamin and mineral deficiencies, which is why it's important to have a registered dietitian help with the best dietary plan.

Page: [[$index + 1]]