For the 10% to 15% of U.S. adults with irritable bowel syndrome (IBS) — a chronic disorder characterized by abdominal pain, gas, bloating and altered bowel habits — mealtimes can feel like a minefield.
Dairy, gluten and artificial sweeteners, as well as many fruits and vegetables, can all potentially cause a person's IBS symptoms to detonate, depending on their unique food sensitivities.
While IBS can't be cured, it can be successfully managed through certain lifestyle changes and, if necessary, medication. Dietary changes, however, are the most foundational of those, says Dr. Neha Mathur, a gastroenterologist at Houston Methodist.
"In many patients with IBS, dietary modifications is an effective non-pharmaceutical option to help minimize or control their symptoms," says Dr. Mathur. "There are many foods that are common in our diet that, when consumed and broken down by our gut, can lead to worsening of these symptoms. These are also commonly categorized as foods high in FODMAP."
What is FODMAP?
FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols — specific types of carbohydrates and fibers that your gut bacteria feed on.
For most people, foods high in FODMAP present no issues. However, for people with IBS and gut sensitivity, the "fermentation" of these specific foods by bacteria can throw off the gut, producing gases and causing fluid imbalances that lead to the hallmark symptoms of IBS, including gas, bloating, swelling and pain.
"A diet low in FODMAPs has become the standard all physicians agree on for IBS dietary interventions," says Dr. Mathur. "There is strong evidence that a low-FODMAP diet helps control and reduce symptoms of IBS and can actually improve quality of life for people with certain chronic conditions."
"Not everyone with IBS is sensitive to all foods high in FODMAP, but these are some of the most common foods that can help someone know where to start," she adds. "Ultimately, each patient will need to have their diet modifications tailored to them."
(Related: Should You Take a Food Sensitivity Test?)
Getting started: the low-FODMAP diet for beginners
While the low-FODMAP diet may be the gold standard for IBS treatment, it can be highly restrictive since many of the foods identified as high in FODMAPs are part of a normally healthy diet. This includes foods like wheat, cauliflower, broccoli, apples, beans and more.
"A low-FODMAP diet can be daunting in the beginning," says Dr. Mathur. "I do not want patients to be excessively restricted to where they are losing weight, which is not the goal of this diet."
The best way to ensure you're correctly and healthfully following a low-FODMAP diet is to work with a registered dietitian, who can guide you through the diet without risking any nutritional deficiencies.
(Related: IBS vs. IBD: What's the Difference?)
Phase 1: Elimination
After consulting a dietitian, the first step in a low-FODMAP diet is the elimination phase, which should last anywhere from four to six weeks and consists of avoiding foods high in FODMAP, according to Dr. Mathur. It'll surprise you just how many foods are high in FODMAP and will need to be eliminated. Dairy and gluten are most commonly the ones people start with eliminating, says Dr. Mathur.
The sign of a successful elimination phase is symptom improvement. However, it's important to know that FODMAP is not meant to be a long-term diet. Rather, after eliminating high-FODMAP foods and seeing symptom improvement, the next step is to gradually reintroduce those foods to identify which ones trigger your symptoms.
Phase 2: Reintroduction
After you have successfully avoided foods high in FODMAP, the next step is to reintroduce one food at a time over a three-day period and note if any of your symptoms return.
If no symptoms recur, you can reintroduce that food back into your regular diet, says Dr. Mathur. However, if what you ate causes any symptoms to come back, it might be what Dr. Mathur calls a "trigger food" — in which case you'll want to keep track of which food it was, limit or avoid it and note any symptoms that it caused.
This process can take anywhere from six to eight weeks on top of the elimination phase.
Phase 3: Management
Finally, after working through the list of high-FODMAP foods (like the one below), Dr. Mathur suggests to patients they then limit or avoid any of their trigger foods in the long run.
Working with a dietitian, you can then formulate an eating pattern based on which foods are likely to trigger your IBS and avoid them and which you can reincorporate. Ultimately, your diet after low FODMAP is going to be tailored to your unique gut sensitivities.
(Related: Tips for Keeping a Healthy Gut)
7 foods that may be making your IBS worse
Here are seven food items — either high in FODMAP or that can cause gastrointestinal distress — that Dr. Mathur recommends people with IBS or IBS-like symptoms may want to try eliminating and reintroducing in their diet to see if they trigger symptoms.
1. Dairy products
Lactose is a natural sugar found in dairy milk and a type of disaccharide — the "D" in FODMAP. Whether you have IBS or not, most people in the world are lactose intolerant to some degree.
This happens when the body doesn't produce enough lactase, the enzyme that helps break down lactose. Without enough lactase, bacteria in your gut begins to ferment the lactose, which creates the hallmark gas, bloating and discomfort associated with IBS and lactose intolerance.
If you have IBS, you may consider eliminating and reintroducing the following dairy products to see if they cause symptoms:
- Ice cream and custard
- Milk from cows, goats or sheep
- Soft cheeses like cream cheese, cottage cheese and ricotta
2. Gluten
"Gluten is a common food category that can cause symptoms even if you don't have celiac disease," says Dr. Mathur. "The studies are mixed, with some showing no difference in consuming gluten where others show improvement in IBS symptoms."
If you do find gluten to be a trigger food on the low-FODMAP diet, then avoiding gluten may be beneficial for those IBS patients, says Dr. Mathur. However, others may not notice a major difference. Typically, most IBS patients with gluten sensitivity will have symptoms that are more of a nuisance compared to those who have celiac disease, an autoimmune disorder in which the body reacts abnormally to gluten, she adds.
If you do decide to eliminate and reintroduce gluten into your diet, you'll want to avoid the following foods:
- Barley
- Beer
- Malt vinegar
- Rye
- Wheat
Wheat, barley and rye contain fructans, a type of oligosaccharide — the "O" in FODMAP.
3. Carbonated beverages
Some IBS patients may also want to avoid soda and other fizzy drinks — even sparkling waters and seltzers — as the carbonation can contribute to further gas and bloating. Moreover, sodas with lots of sugar or artificial sweeteners may contain one — or more — of the FODMAPs.
If you just need that fizzy burn, you may try eliminating and reintroducing soda as part of the low-FODMAP diet.
4. Certain fruits and vegetables
So many fruits and vegetables contain one or more of the FODMAP carbohydrates you'll want to avoid on the low-FODMAP diet. This is why working with a dietitian is so important in making sure you still get good nutrition while eliminating these otherwise healthy and nutritious foods.
Some of the fruits and vegetables high in FODMAPs include but aren't limited to:
- Apples
- Apricots
- Asparagus
- Avocados
- Blackberries
- Beets
- Celery
- Cherries
- Cruciferous vegetables like broccoli and cabbage
- Fennel
- Green bell peppers
- Legumes, beans and pulses
- Mangos
- Mushrooms
- Peaches
- Pears
- Pistachios
- Plums
- Sugar snap peas
- Sweet corn
- Watermelon
5. Sweeteners
"A diet rich in sugars or artificial sweeteners that have non-absorbable components like sorbitol, mannitol and xylitol can also create more gas or bloating due to changes in bowel fluid levels and increase fermentation," says Dr. Mathur.
Most of the following sweeteners contain or are a type of monosaccharide or polyol — the "M" and "P" in FODMAP — which you'll want to avoid during the elimination portion of low-FODMAP and try reintroducing to see if they trigger any symptoms:
- Agave nectar
- Erythritol
- Honey
- High-fructose corn syrup
- Sorbitol
- Mannitol
- Molasses
- Xylitol
6. Red meat
While red meat is not technically a high-FODMAP food, red meats like beef and pork are generally harder for the gastrointestinal tract to digest, which can contribute to enhanced symptoms if your diet is heavy in these types of proteins, says Dr. Mathur.
Instead, people with red meat sensitivities will want to choose leaner proteins like chicken and fish, which are generally easier to digest, she says.
7. Alliums
Garlic, onions and other similar-smelling vegetables are part of the allium family and contain oligosaccharides — the "O" in FODMAP. As part of the low-FODMAP diet, you'll want to consider avoiding the following and try reintroducing them to see if you notice any symptoms:
- Chives
- Garlic
- Green onions
- Leeks
- Onions
- Shallots
What else besides low FODMAP can help calm IBS symptoms?
More soluble fiber
Soluble fiber, both in the forms of foods like chia seeds and ground flax and supplements like psyllium husk, can help loosen bulk stool and reduce bloating, says Dr. Mathur.
Peppermint
Believe it or not, peppermint can also help reduce IBS-associated abdominal pain and cramping, says Dr. Mathur. Menthol, a chemical compound found naturally in peppermint and other mint plants, acts as a muscle relaxer and can be an anti-spasmodic agent, she says.
Yogurt
While most dairy is considered high in FODMAP, yogurt as a fermented dairy product not only has much less lactose in it compared to unfermented dairy, but it also contains probiotics that make the lactase enzyme, which helps break down lactose, Dr. Mathur says.
Probiotics
Probiotics can be beneficial for IBS, but only to a certain extent, according to Dr. Mathur.
"One of the theories behind why people have IBS is that they may have a different gut microbiome balance than someone else with no symptoms," she says. "Using probiotics to manipulate the microbiome can have beneficial effects. IBS patients tend to have lower colonies of lactobacillus and bifidobacterium in their microbiomes, so taking a probiotic with these microorganisms can help reduce some of the symptoms."
That said, data is still not strong with probiotics, and a lot is still unknown about which microorganisms work best in the first place, as well how long you should take them.
Lifestyle changes and behavioral interventions
Low FODMAP isn't the only lifestyle and behavioral intervention shown to help IBS. Because IBS is associated with a dysfunction between the brain and gut (also called your brain-gut axis), factors that can affect your mood may also influence your gut health, according to Dr. Mathur.
Exercise and good sleep hygiene are both essential components of IBS treatments, while mindfulness exercises, yoga, meditation, acupuncture and massages are all things that can help further improve the overall function of our body and brain-gut connection, says Dr. Mathur.
Additionally, addressing any underlying mood disorders like depression and anxiety through therapy can also benefit the brain-gut connection, she says.
Bowel medications
IBS has three most common types: IBS-C (constipation predominant), IBS-D, (diarrhea predominant) and IBS-M (mixed bowel habits). The low-FODMAP diet can help with all three types of IBS, says Dr. Mathur, but depending on which type you have, certain treatments and medications can be used, such as stool softeners, laxatives or anti-diarrheal medicine.
(Related: When to See a Doctor for Diarrhea)
When should you see a gastroenterologist for your IBS symptoms?
"If any IBS symptoms are persistent for more than a few months and are either getting worse or not responding to dietary modifications, I always recommend people to seek expert consultation," says Dr. Mathur.
You'll want to seek care even sooner if you notice any "red flag" symptoms such as bloody stool, unintentional weight loss or severe changes in bowel habits, she adds.
(Related: What Your Stool Says About Your Health)
