FODMAP

What is it?

FODMAP stands for fermentable, oligosaccharides, disaccharides, monosaccharides, and polyols. These are short-chain carbohydrates that are may be difficult for some people to absorb, causing gastrointestinal (GI) symptoms like diarrhea, constipation, cramping, bloating, gas, flatulence, and stomach pain. It is often a diet that is prescribed for people with IBS to allow the gut to rest. This is not meant to be a long-term diet as the goal is to reintroduce foods slowly again to identify what specifically might be causing the symptoms.

Fermentable: foods that the gut bacteria feed on which ferments into gasses.

Oligosaccharides: soluble fibers from plants that feed the beneficial gut bacteria, also known as prebiotics. They include onions, garlic, beans & lentils, and wheat products.

Disaccharides: consists of lactose which is the sugar in dairy and human milk.

Monosaccharides: consists of fructose, or the sugar in fruit.

Polyols: sugar alcohols used as artificial sweeteners, also found naturally in some fruits.

What does it do?

It is an elimination diet that allows the gut to rest, enabling the lining of the gut to heal. It can restore balance of the healthy gut bacteria while identifying foods that someone may want to avoid.

What does the research say?

Studies show that the low-FODMAP diet can reduce IBS symptoms for the majority of patients who try it. However, because it is challenging to manage, and cuts out important groups of food, it is highly recommended that anyone trying it work closely with a registered dietitian. In addition, it is meant to be a short-term approach to managing IBS symptoms. More studies are required to understand the potential side effects of adhering to this diet long term.

What are the downsides?

A multi-phase approach is required.

• Phase 1 usually consists of eliminating high FODMAP foods for approximately 2-6 weeks.

• Phase 2, which can take place over 8-12 weeks is the reintroduction phase. One high FODMAP food is introduced at a time, over a few days, to identify if it causes any unwanted symptoms.

• Phase 3 is about personalization. After following phases 1 and 2, foods that can't be tolerated have been identified. A patient then knows which high FODMAPS to avoid and which ones are okay.

While this way of eating may resolve symptoms associated with IBS and SIBO (Small-Intestinal Bacterial Overgrowth), it is a complex process which requires a lot of discipline and support. It's important that a dietitian is involved in each phase to make sure phase progression is happening correctly and foods are being re-introduced appropriately. If when reintroducing a food symptoms are experienced, phase 1 must begin again. As a result this diet can take a long time.

Failing to reintroduce foods may produce nutritional deficiencies and contribute to a further imbalance in the gut microbiome. This has the potential to worsen the digestive issues that required this diet in the first place.

In addition, this way of eating may not be for everyone. Someone already on a restricted diet, like vegan, may wish to avoid trying a low-FODMAP. Also, people who are experiencing eating disorders, are underweight, or malnourished may want to avoid it.

Bottom line

This may be worth trying if you suffer from IBS and related symptoms, however, do not try it alone. Seek help from a trained dietitian who will be able to guide you through each step, help you begin to reintroduce foods slowly again, provide information on dietary supplementation if needed, and ensure you’re achieving a healthy gut.

References

Cleveland Clinic. (2022, February). Low FODMAP Diet. Retrieved from https://my.clevelandclinic.org/health/treatments/22466-low-fodmap-diet

Gelsomin, E. (2020, July 20). The lowdown on the low-FODMAP diet. Harvard Health Publishing. Retrieved from https://www.health.harvard.edu/blog/the-lowdown-on-the-low-fodmap-diet-2020072720662

Monash University. (n.d.). What is the purpose of a FODMAP diet? Retrieved from https://www.monashfodmap.com/ibs-central/i-have-ibs/starting-the-low-fodmap-diet/

Veloso, H. G. (n.d.). FODMAP Diet: What You Need to Know. Johns Hopkins Medicine. Retrieved from https://www.hopkinsmedicine.org/health/wellness-and-prevention/fodmap-diet-what-you-need-to-know