The low FODMAP diet can be very helpful for irritable bowel syndrome (IBS). It has been shown to decrease gas, bloating, abdominal pain, diarrhea, and may also help constipation. Some have expressed concern that a low FODMAP diet decreases intestinal bacteria, which is debatable. However, exciting evidence shows a low FODMAP diet can reduce leaky gut, calm the immune system, and even repair the intestines. Let’s discuss.
Healing Leaky Gut with a Low FODMAP Diet
Dr. Michael Ruscio: Hey, everyone. This is Dr. Ruscio, and let’s discuss how the low FODMAP diet works. Now, if you’re not familiar with the low FODMAP diet, this is a diet that restricts what may seemingly be some healthy foods, like asparagus, because these foods are actually very powerful at feeding gut bacteria.
And for some people who have potentially too much gut bacteria to begin with, eating foods that feed those gut bacteria can actually make them feel worse. And there’s been quite an impressive amount of clinical literature showing that the low FODMAP diet can be very helpful for those with IBS and those with IBD, irritable bowel syndrome and inflammatory bowel disease.
Now, with IBS, typical symptoms are gas, bloating, abdominal pain, diarrhea or loose stools, and/or constipation. And actually, the symptoms are very similar for IBD, inflammatory bowel disease, typically presenting as ulcerative colitis and Crohn’s. And there have been a number of clinical trials that have shown benefit, even double-blind trials, showing benefit with the low FODMAP diet.
So if you’re someone with digestive ailments, then the low FODMAP diet is certainly a consideration. However, what sometimes concerns people is because these diets in effect starve bacteria, because these diets cut out foods that feed bacteria, so they, therefore, then can starve bacteria. People have expressed concern that perhaps you are going to cause a negative consequence to your intestinal bacteria.
And I do not think that this is actually fully borne out, and I’ll be presenting an expanded presentation on this at the 2017 Ancestral Health Symposium in Seattle. But I wanted to give a few kind of highlights from the presentation that I’ll be giving here really quick. And I apologize, I’m not super prepared. But I wanted to share these few insights with people.
Firstly, there’s not consistent data that shows that the changes in the microbiota or the gut bacteria that occur after a low FODMAP diet are bad. There actually may be some good changes that occur also when you look at the microbiota and when you look at, I’m sorry, the studies more broadly.
But I want to get us off of the tunnel vision of the gut bacteria, because there may be other things that improve, that are important and that may be more important than the gut bacteria in the gut when you go on a low FODMAP diet. And these may be, namely, an improvement in what’s called enteroendocrine cells, an improvement in leaky gut, and then, thirdly, an improvement in histamine.
And so, I’ll put one study up here on the screen. And you can read through the details. I’m sorry I didn’t have a chance to kind of consolidate this. But this is one of the slides I’ll be going through. Dietary guidance normalizes large intestinal endocrine cell density in patients with irritable bowel syndrome.
So essentially, what this study is showing is that in patients with irritable bowel syndrome, they have different densities of zone as enteroendocrine cells in their intestines. And these are partially responsible for the release of serotonin, which is something that helps with motility and flow of food and also pain reception in the gut.
So a low FODMAP diet has shown the ability to help make the density of these cells in the intestines more like that of healthy controls. So the low FODMAP diet actually improves some of the enteroendocrine cells in the intestines and makes them look more like that of healthy controls.
So this may be one often overlooked mechanism as for why the low FODMAP diet is helpful. And I’ll also put up here a chart where you can see, in this study, they actually took biopsies before and after low FODMAP diet in IBS patients and compared those to biopsies of healthy controls. And we see that the intestinal cells actually become more like that of healthy controls when you go on the low FODMAP diet. So this may be a major mechanism that has been overlooked, if nothing short of something that’s very interesting.
Secondly here, I wanted to share two findings about leaky gut and histamine. So this next study, the “Low FODMAP Diet Modulates Visceral Nociception by Changing Gut Microbiota and Intestinal Permeability and IBS.” That last piece, intestinal permeability and IBS—the low FODMAP diet did show the ability to decrease leaky gut as measured by LPS or lipopolysaccharide. So the low FODMAP diet may help with leaky gut.
And then third and finally here, this next reference, “FODMAPs Alter Symptoms and Metabolome of Patients with IBS, a Randomized Controlled Trial.” Essentially, what they found was there was an improvement in markers of immune activation, most namely here, histamine. Histamine is a signaling molecule in the gut, and this may indicate that people with IBS, and I would also argue potentially with IBD, may have a skewed immune system in the gut. And I’ve made this argument before.
And we may need to play by different rules, so to speak, if someone does not have a healthy gut immune system. We may not want to just try to increase their gut bacteria, increase their gut bacteria, increase their gut bacteria, because the immune system in the gut may not get along well with those gut bacteria. So this may be why a low FODMAP diet is helpful, because a low FODMAP diet prunes the microbiota or trims the shrubs, so to speak, and that then is liked by the immune system. And this causes a more harmonious environment in the gut at large.
So those were a few studies that I wanted to share that I think highlight some important findings regarding the low FODMAP diet, which is it may work for reasons outside of just bacteria. And in light of this boom of research and interest that’s occurring in the microbiota, in the gut bacteria, in the world of bacteria in your gut, it’s important not to become tunnel-visioned into only thinking about things through the lens of gut bacteria.
And as I’ve outlined for you here, first and most important, the clinical literature clearly shows the low FODMAP diet can be very helpful for those with IBS and for those with IBD. That’s the first and most important thing. Second, we shouldn’t overly obsess over changes in bacteria if we see positive clinical improvements occurring.
And then, thirdly, we should be open to other mechanisms that may not be bacterial-dependent that may account for why the low FODMAP diet works so well clinically.
Most namely here, we see an improvement of the enteroendocrine cells in the intestines. We see a reduction of leaky gut, and we see a reduction of histamine, a signaling molecule involved with the immune system. So for all these reasons, it’s important to keep in mind that we want to make decisions, first, based upon clinical outcome, and then try to essentially find the mechanisms that account for that, and not become overly skewed into looking at one potentially in vogue measure of the microbiota and potentially getting a negative outlook on the low FODMAP diet because of what’s happening, because of the bacteria, and make sure we have a broad examination of the data and make a decision that accounts for all these things.
So in my opinion, the low FODMAP diet, certainly there’s more to learn about it, but for those with IBS and IBD, it can be very helpful. And it may be helpful for reasons other than gut bacteria, most namely the cells in the intestines, leaky gut, and the immune system in the intestines.
So if you’re finding benefit from the low FODMAP diet but you’re concerned that it may cause a dwindling of gut bacteria, I wouldn’t worry about it. Also, if you haven’t tried the low FODMAP diet because you heard it can cause a dwindling of gut bacteria, I also would try it. It’s also important to mention that after about four to eight weeks on the low FODMAP diet, you should then reintroduce foods to tolerance and try to push out to the broadest diet possible.
It’s not necessarily that we have to be on a restricted, very low FODMAP diet in perpetuity. We start there, see how much gain we can achieve clinically, and then reintroduce to tolerance. And most patients will be able at least to introduce some, if not many, higher FODMAP foods in the longer term with no problem.
So, this is Dr. Ruscio, and hopefully this information helps you get healthy and get back to your life. Thanks.
What do you think? I would like to hear your thoughts or experience with this.
Dr. Ruscio is your leading functional and integrative doctor specializing in gut related disorders such as SIBO, leaky gut, Celiac, IBS and in thyroid disorders such as hypothyroid and hyperthyroid. For more information on how to become a patient, please contact our office. Serving the San Francisco bay area and distance patients via phone and Skype.