If you have IBS or SIBO, you may have heard of the low FODMAPs diet, sometimes called the IBS diet. Maybe your doctor recommended you try it and gave you a long list of foods to avoid. But you feel confused—what exactly are FODMAPs? Does this diet really work for gut problems like IBS or SIBO? Is a low FODMAPs diet a healthy long-term solution to your gut problems?
Let’s start at the beginning: what the heck is a low FODMAPs diet?
FODMAPs is the acronym for Fermentable Oligosaccharides Disaccharides Monosaccharides And Polyols. These are short-chain carbohydrates found in many foods like beans, dairy, fruits, and veggies. Once in your gut, FODMAPs pull water into your intestine and are resistant to absorption, meaning they hang out in the gut a little longer than other carbs. Your gut bacteria begin to ferment them, which creates extra gas that can cause symptoms like bloating, distension, diarrhea, and even pain. A diet low in FODMAPs helps reduce these symptoms for many sensitive people.
Studies have shown that a low FODMAPs IBS diet effectively reduces symptoms for around 70% of those with IBS (1, 2, 3).
But for the remaining 30%, a low FODMAPs diet is not helpful (1).
Why could that be? Well, IBS is a complex condition with many moving parts. Gut dysbiosis, or an imbalance of beneficial to potentially harmful gut bacteria, is not the only contributing factor to IBS symptoms. Sensitivity to psychosocial stress, heightened visceral sensitivity (aka pain in the inner organs that those with IBS often experience), and ultra-enhanced gut-brain communication may all contribute to symptoms (3). And a low FODMAPs diet seems to benefit those with IBS-D (diarrhea) more than IBS-C (constipation) due to the decrease in dietary fiber associated with most low-FODMAPs eating plans (3,4).
As far as SIBO goes, there isn’t much hard science looking at the therapeutic benefits of a low FODMAPs diet (5). However, for many practitioners, a low FODMAPs diet is part of the SIBO protocol since it can help reduce symptoms while SIBO is being treated. The reasoning is simple—SIBO means an overgrowth of bacteria, and a low FODMAPs diet reduces fuel for those unwanted bacteria.
However, researchers have found a strong association between IBS and SIBO. It is estimated that anywhere from 4% to 75% of IBS patients have SIBO, and the actual number might be close to 50% (6).
In the real world, this could mean that many folks are misdiagnosed with IBS when SIBO is the true culprit of their gut issues. This is a critical point to investigate…could approximately half of people diagnosed with IBS need treatment to eradicate SIBO?
The connection between IBS and SIBO may also be because some people with IBS are at higher risk of developing SIBO due to slower gut transit time (7).
SIBO treatment is intensive and often needs repeating. It includes targeted antibiotic therapy with either conventional antibiotics or herbal antimicrobials needed to kill off unwanted bacteria, as well as compounds that positively alter intestinal function.
The point is, SIBO can’t be eradicated with diet alone – so why aren’t more medical professionals testing for SIBO? Especially when their patients’ IBS symptoms get *almost* better with a Low-FODMAPs diet? Honestly this is one of my pet peeves and why I advocate for testing, not guessing!
A low FODMAPs IBS diet comes with challenges. It is restrictive, expensive, and not intended to be a long-term solution for IBS (2) or SIBO.
If you have ever done an elimination diet, you know that the reintroduction phase is crucial. (Just ask anyone in the Good Poopers Club™!) The same is true for a low FODMAPs diet—the reintroduction of FODMAPs is critical to properly determine which foods lead to symptoms. Working with a nutritionist is vital for success as you don’t want to permanently eliminate dozens of foods without good cause.
And this is where things get a little muddy, so let’s clarify them! High FODMAPs foods aren’t unhealthy or destructive. In fact, quite the opposite! High FODMAPs foods contain beneficial prebiotic fibers that are important for gut health, so long-term avoidance of these foods isn’t recommended. The good news is that the benefits of a low FODMAPs diet can be sustained after selective FODMAPs reintroduction (6). This simply means that everyone reacts to FODMAPs foods differently—you may remove a dozen foods during the initial phase but then discover you are only sensitive to one or two after reintroduction.
Interestingly, strain-specific probiotics may be just as effective as a low FODMAPs diet when it comes to improving IBS symptoms (4, 8).
When researchers compared a low FODMAPs diet to regular probiotic supplementation in a group of patients with IBS, they found that the probiotic supplements Lactobacillus rhamnosus GG and VSL#3 worked equally as well as a low FODMAPs diet (4,8). And guess what? Lactobacillus rhamnosus GG is available at most drugstores in the US under the brand name Culturelle™.
If trying a low FODMAPs IBS diet sounds overwhelming to you, probiotic supplementation might be a good place to start, along with focusing on a nutrient-dense diet. Also, consider yoga or meditation, as these have been shown to help calm IBS (9). Finally, removing ultra-processed foods is beneficial for IBS and SIBO since common food additives like artificial sweeteners, emulsifiers, and food coloring can harm the gut and worsen symptoms (10).
If, however, you’re ready to deal with your diet and investigate any underlying causes of IBS, SIBO or FODMAPs intolerance – book a call with me and we can talk about your options!