FODMAP: why this acronym could change your diet

What is the FODMAP diet? Does it cure irritable bowels? How does it work?

It's helpful to review some physiology first. If you've read our article on GI basics, you already know that the function of the colon (aka the large intestine) is to move water in and out of its tube to form your poop. Compared to other parts of your GI tract, what you eat will spend most of its time in the colon - an average of 30 hours. Throw trillions of bacteria into the mix (aka your Gut Microbiome) and it becomes quite clear thirty hours is a long time for what's left of your food to cause you problems. Among millions of other functions that we are continuing to learn about, the bacteria in your gut functions as kind of a last man standing before what you ate leaves your body. As a result, it is trying to break down whatever it can from what's left at this point, and doing so can in part be responsible for generating GI symptoms of constipation, diarrhea, bloating, and gas.


What is the FODMAP diet?

Needless to say, choosing foods that ease your colon's job can help minimize your GI symptoms. That's the basic concept behind the FODMAP diet. The acronym is simply a list of fermentable carbohydrates (Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols) that may spell trouble for your gut bacteria. If you're someone sensitive to foods that have high amounts of FODMAPs in them, that food in your colon will either not be absorbed, drawing water into your colon (aka diarrhea), or hang out longer in your colon (aka constipation) and be broken down through fermentation by your gut bacteria (aka bloating and gas). Some people's guts are very sensitive to these processes, leading to abdominal pain that is relieved with bowel movements.


Does the FODMAP diet cure IBS?

If that constellation of symptoms sounds familiar, it's because the medical diagnosis it's associated with is Irritable Bowel Syndrome (IBS). To be clear, it's not just FODMAPs that cause the symptoms of IBS, but there is a portion of the IBS community that improve dramatically with a low-FODMAP diet. We will be writing a ton on IBS, which is unnecessarily stigmatized in part due to the medical community's still growing understanding of its pathogenesis.

FODMAP has almost exclusively been studied as a diet to reduce symptoms of IBS, and while we are still learning about its longterm effects on the microbiome, current data is promising. The implications of minimizing stress on your gut may be far reaching, but we are still studying how low FODMAPs affect the non-IBS community. If you're not intolerant to FODMAP foods (see the link below for examples) there's no reason to be exclusive about what you eat, and in fact the major issue that people strict with any diet often run into is not getting enough dietary fiber.


Is the FODMAP diet helpful for people without IBS?

Embracing a low FODMAP diet or even simply being mindful of high FODMAP foods can be incredibly useful in correlating your GI symptoms with what you ate, keeping in mind the time it takes for that food to get to your colon in the first place. There's nothing inherently wrong with high FODMAP foods, and I don't want the takeaway here to be that everybody should avoid them. Your gut may have no problem digesting these fermentable carbohydrates, but knowing what foods may cause you problems is the first step towards a healthier gut.

An important point is that the FODMAP diet is restrictive, and is only meant to be temporary followed by gradual reintroduction of foods as tolerated. I highlight this because it is important - studies have shown strict adherence to a FODMAP diet can lead to nutritional deficiencies, and if used for long periods of time can decrease the diversity of your gut microbiome. As with any dietary approach, making sure you are eating healthy, natural foods is always first and foremost - let FODMAPs guide but not absolutely restrict your diet and lifestyle.

-The Gut Doc


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