Medical professionals first used the term irritable bowel syndrome (IBS) in 1944. Since then, doctors and scientists have worked hard to find the best treatment. Still, many things – including the cause – of IBS are still unknown.
However, researchers have made a lot of progress over the last few decades. They discovered dietary factors are key players in IBS. Certain foods can trigger flare-ups while others improve symptoms.
Which diet is best for someone with IBS? Keep reading to find the best IBS diet out there.
Low FODMAP Diet
Monash University in Australia first discovered the low FODMAP diet a decade ago. They continue to research this diet and provide extensive education for patients and healthcare professionals. FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. These sugar molecules are poorly absorbed and trigger IBS symptoms.
The low FODMAP diet is the most researched diet for IBS. It is scientifically proven to help alleviate IBS symptoms. There is a lot of information about the low FODMAP diet on the internet. Some provide inaccurate information about what you can and cannot eat. However, Monash University is the best resource to refer to about the diet.
How the Low FODMAP Diet Works
Those with IBS cannot properly absorb FODMAP sugar molecules. They are small in size and attract water to the intestine. When they reach the large bowel, the gut bacteria ferment them. This causes gas, bloating, abdominal pain, constipation, and/or diarrhea.
You can enjoy plenty of low FODMAP foods and consume small amounts of moderate FODMAP foods. Avoid high FODMAP foods during the first phase (2-6 weeks) of the diet known as the elimination phase. During the second phase or rechallenge phase, you’ll slowly reintroduce high FODMAP foods. This gives you a chance to see how you react to them. After six to eight weeks, you’ll start the third phase of the diet. In this phase, you’ll reintroduce the FODMAP foods you can tolerate well.
High and Low FODMAP Foods
The low FODMAP diet can feel restricting because there are some foods you cannot eat.
Examples of high FODMAP foods include:
- Green peas
- Processed meats
- Grains containing gluten
- High fructose corn syrup
Try to avoid these foods if you have IBS symptoms.
Low FODMAP vegetable and fruit alternatives include:
- Bok choy
- Bell peppers
- Maple syrup
- Table sugar
- Dark chocolate
- Most nuts
Downloading the Monash app can be very helpful to track what foods you can eat.
Many people with IBS benefit from a gluten-free diet. Research continues to confirm these benefits. Grains that contain gluten have a sugar called fructans, which can trigger IBS.
One study found a gluten-free diet improves IBS symptoms, particularly diarrhea. Gluten sensitivity is becoming more prevalent nowadays. There is also a link between this sensitivity, increased gut permeability, and autoimmune diseases. IBS seems to be associated with both nonceliac gluten sensitivity and celiac disease.
It is worth trying a gluten-free diet for 6-8 weeks. During this time, keep a journal and track symptom improvement. Be aware that gluten hides in many processed foods, sauces, dressings, and desserts. It isn’t only in pasta and bread. Opt for gluten-free foods, cook at home, and consume whole foods.
High Fiber/Low Fiber Diets
Those with IBS predominant constipation (IBS-C) may benefit from an increase in fiber. Add 2-3 grams of fiber daily to your diet until you reach 25 grams (for women) or 38 grams (for men) a day.
It is important to track your fiber intake, as many adults do not eat more than 5-14 grams daily. Fiber adds bulk to the stools, promoting a normal bowel movement. Therefore, relieving constipation.
In case of excess gas and bloating, choose to consume more soluble fibers. Foods with soluble fibers include carrots, sweet potatoes, nuts, and seeds. Less insoluble fibers are in cereals, bread, pasta, apples, lentils, and avocadoes.
However, those with predominant diarrhea IBS (IBS-D) should avoid high amounts of fiber. High-fiber fruits and vegetables can trigger diarrhea symptoms. The general recommendation is to consume fibers in moderation. Some feel better on a low fiber diet. Others choose to take anti-diarrheal medication 30 minutes before consuming a fiber-rich meal.
Whether you choose a low FODMAP, gluten-free, or low/high fiber diet, it is important to talk to your healthcare provider. These diets are restrictive and foods should be carefully replaced with others. You may also need to take supplements to avoid nutrient deficiencies as well.