Can a Low-FODMAP Diet Help Your Digestion?

Have you been experiencing abdominal pain, bloating, and alternating diarrhea and constipation but can’t find the cause? Do your symptoms get worse after eating certain foods, or get better after you have passed stool? Have you heard of irritable bowel syndrome (IBS)? Did you know that a low-FODMAP diet can help alleviate IBS symptoms? Read on to learn more from Beijing United Family Hospital (BJU) Dietitian Jackie Gao about how you can manage your IBS symptoms using this diet. 

What is irritable bowel syndrome? 

IBS is a common functional disorder that can cause a number of gastrointestinal symptoms, including abdominal pain, excessive wind, bloating, and alternating constipation and diarrhea. Anyone can suffer from IBS, but it is more common in younger adults and more common in women than men. It is often diagnosed after normal investigations once more serious diseases are ruled out but symptoms remain. We often diagnose ourselves with it, but ideally what you should do is speak with a gastroenterologist or family medicine doctor who will help you confirm the diagnosis of IBS. To learn more about IBS, please read BJU Gastroenterologist Dr. Neil Galletly’s article about the disease. 

The symptoms of IBS can cause discomfort or embarrassment at times – especially if we are out with friends or in public. However, there is no one-size-fits-all treatment. Dietary modification is one of the treatments that shows the most promise and it is often preferred to taking medication. The good news is that clinical evidence shows that the low-FODMAP diet can help alleviate symptoms in up to 70% of patients with IBS – particularly when it comes to bloating and abdominal pain. 

What are FODMAPs? 

FODMAP is an acronym for a group of fermentable short-chain carbohydrates listed below. They all share the same property of being poorly absorbed and digested by our intestines and instead they are rapidly fermented by bacteria in the gut. 

Fermentable 

Oligosaccharides (fructans and galacto-oligosaccarides, found in wheat, onions, and garlic)

Disaccharides (lactose, found in milk and milk products)

Monosaccharides (fructose in excess of glucose, found in certain fruits and honey)

And 

Polyols (e.g. sorbitol and mannitol, found in some fruits and sometimes added as artificial sweeteners)  

The amount of FODMAPs varies from food to food, but we can generally group foods into either high- or low-FODMAP groups. Some common foods are listed below. 

Please note that this table is not an exhaustive list of high- and low-FODMAP foods.

The picture below may help you understand what happens in the gut. When we eat foods containing a large amount of FODMAPs (from either one or many FODMAP groups), these carbohydrates are poorly absorbed in the small intestine. As a result, they either draw water into the small intestine (which can cause diarrhea in some people) or travel farther down to the large intestine where they are fermented by bacteria and cause gas, which may lead to bloating, abdominal pain, wind, or constipation. Following a low-FODMAP diet may help alleviate some or all of these symptoms.

Image source: www.monashfodmap.com

How do I implement the low-FODMAP diet? 

The low-FODMAP diet involves three steps:

1. Reduce the total FODMAP content in the diet by replacing high-FODMAP foods with low-FODMAP alternatives in the same group. This process usually takes two to six weeks and may take longer if not followed properly. 

2. Reintroduce FODMAPs back to your diet. If you are considered a “responder”, you will be ready to reintroduce some foods that you have been missing back into your diet one group or one food at a time. You will need to monitor your symptoms as you increase the serving size of each high-FODMAP food to find out which FODMAP(s) cause(s) symptoms. This process usually takes six to eight weeks or longer. 

3. Personalize your diet plan so that you find a fine balance between tolerated high-FODMAP foods and the avoidance of others.

You will find the diet much easier to follow if you cook your own meals.

What if my symptoms don’t improve after I try the diet?

If you have strictly followed the diet for a period of time but have achieved minimal or no improvement, it may turn out that there is no one food that is to blame for your symptoms. It may also help direct you to non-diet solutions. Nevertheless, a big part of following the diet is learning about the foods you eat, whether it’s learning how to adopt healthy eating habits, read food labels for packaged foods, find alternatives when eating out, or not miss out on special occasions with an irritable bowel. 

Can I do the FODMAP diet myself?

It is highly recommended that you try the low-FODMAP diet under the guidance and supervision of a dietitian specializing in this field. Good reasons include:

1. This is not a one-size-fits-all treatment for IBS. 

2. A well-designed and personalized meal plan involves good discussion with you and your dietitian so that a realistic and healthy meal plan can be implemented.

3. You will do yourself a favor by following the low-FODMAP diet systematically in order to avoid unnecessary lengthening of the diet duration, and only restrict foods that trigger symptoms in the long run.

4. Long-term implementation of the low-FODMAP diet may alter the balance of gut bacteria by decreasing the amount of good bacteria, which may not be desirable in the long run. 

Can children with IBS do the low-FODMAP diet? 

Yes. Children from the age of 1-2 years can try a low-FODMAP diet trial as long as they have a confirmed diagnosis of IBS and the diet is done under the supervision of an experienced dietitian specializing in gastrointestinal diseases. It is important for the child to avoid unnecessary dietary exclusions, nutrient deficiency, or slowed growth. Our Nutrition Consultant Jackie Gao has over three years of experience with helping children with IBS at Sydney Children’s Hospital before joining Beijing United Family Hospital and was involved in a research project on the subject there as well. 

What do I do if I want to try the low-FODMAP diet? 

1. Confirm your diagnosis. See a gastroenterologist to rule out more serious conditions that may explain your symptoms. If your results are normal and your gastroenterologist feels that you may benefit from a low-FODMAP diet, he/she may refer you to see a dietitian.

2. Start observing your symptoms. Observe any links between what you eat/drink and your symptoms. It may tell you a lot about whether the diet can help. 

3. Find a dietitian who specializes in gastrointestinal diseases to guide you through the low-FODMAP diet trail and provide ongoing support.  

References:

1. Altobelli E, Negro VD, Angeletti PM, Latella G. Low-FODMAP diet improves irritable bowel syndrome symptoms: a meta-analysis. Nutrients 2017, 9, 940; doi:10.3390/nu9090940

2. Gibson PR, Shepherd SJ. Evidence-based dietary management of functional gastrointestinal symptoms: the FODMAP approach. J Gastroenterol Hepatol. 2010;25:252–258.

3. The low FODMAP diet. https://www.monashfodmap.com 

Jackie Gao is a Chinese-born, Australian-trained dietitian and nutritionist. To make an appointment with her, please call our service center at 4008-919191.

• What is IBS anyway? Gastroenterologist Dr. Niel Galletly digs deeper here.

• Having digestive issues but they don't sound like IBS? Read about acid reflux to see if that's what you might be suffering from. 

• Interested in diverticulitis? Read more here!