Should You Go Low Carb If You Have IBS?

Is feeding your microbiome the best approach if you struggle with IBS or other digestive issues? According to the data, this may not be the best approach for a variety of reasons.

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Is there a consensus for the amount of carbs that are best for digestive issues like IBS? According to the data, there is a consensus that a lower carbohydrate approach may be more tolerable if you’re experiencing digestive problems.

A couple of protocols to consider include:

Paleo diet

• This is a good place to start. The paleo protocol removes a lot of common allergenic foods like gluten, dairy, and refined sugars. By removing these foods, you’re removing common sources of carbohydrates.

Low FODMAP

• This is a great option if you need to reduce the amount of fermentable carbohydrates that feed bacteria. It’s been shown to significantly help those with IBS. The low FODMAP diet isn’t necessarily a low carb diet, but it reduces certain types of carbs that may be contributing to your symptoms.

Other diets to consider that are helpful for digestive problems include the Specific Carbohydrate Diet (SCD) and the Fast Track Diet.

Experiment with a couple of diets to see which one works best for you. The carbohydrate component is usually addressed as part of the guidelines in that particular diet.

Some people do better on a paleo or low FODMAP diet that is a little higher in carbs. Others do better on one of these protocols that is lower in carbs. Start out with lower carb and slowly increase your carb consumption to find your tolerance level.

How does the microbiome influence this? Do people with digestive issues need to feed their bacteria in order to feel better?

For many people with digestive issues, feeding your bacteria is not the best approach. The healthier a person is, the better they tend to do with foods that feed the microbiome, like fiber and prebiotics. This helps bulk the stool and make bowel movements easier and more consistent.

The challenge if you have digestive issues is that the bacterial feeding approach tends to be problematic and exacerbate symptoms. You may need to design your diet and supplement program around limiting your bacterial growth.

One study of 20 patients with IBS were put on the low FODMAP diet for 3 weeks. 85% of the patients experienced a notable improvement in their symptoms. From there they were divided into two groups.

One group stayed on low FODMAP and one group started on 16 grams per day of FOS (fructooligosaccharides). 80% of the low FODMAP group maintained their improvements. Only 30% of the FOS group maintained their improvements.

In this case, prebiotics don’t seem to be very helpful. The people on the low FODMAP diet saw improvement in their symptoms and inflammation. However, there were some markers, such as microbiota levels and SCFA (short-chain fatty acids), that looked less healthy on paper even though the patient felt significantly better.

There is another component that has to do with the immune system and the gut that is pretty interesting. A key mediator of the immune system and the gut is histamine. If your immune system in your gut activates, that causes a release of histamine. Also, if you have too much bacteria in the gut, those bacteria release histamine, which can cause further immune activation. Histamine and gut bacteria are strongly linked.

Many people do not have healthy immune systems. You may be prone to over-activation of your immune system.

It has been shown that while following a low FODMAP diet, you may yield an eight-fold decrease in histamine. This may be another component of why a low FODMAP diet is helpful.

Another argument that comes up sometimes is once you have healed your gut, then you can go on a higher fermentable protocol. This does have some truth to it. We recommend starting on a more narrow, lower fermentable diet, and then begin adding in more foods and more variety. The goal for you is to find the broadest, most diverse diet that makes you feel good.

However, looking at another study in patients who were in remission from Crohn’s disease, half of the patients went on a high FODMAP diet and they saw a doubling of their symptoms. So ramping up your fiber and prebiotics once you’re asymptomatic may not be the best idea.

Diet is probably the best way to get some prebiotics in your system rather than fiber supplements, which are more concentrated.

Again, someone who is super healthy would probably be just fine with a high FODMAP diet. However, those with imbalances in the gut may find high doses of fiber and prebiotics to be problematic.

Despite all the expert claims that say you must feed your microbiome to be healthy, if you have a compromised digestive system, you may do best limiting certain carbohydrates, fiber, and prebiotics in your diet.

You know your body better than anyone. Listen to it, and feed it in a way that helps you thrive.

For more information on the best diets for gut health, check out our podcast here.

What do you think? I would like to hear your thoughts or experience with this.

• Get help using this information to become healthier.
• Get your personalized plan for optimizing your gut health with my new book.
• Healthcare providers looking to sharpen their clinical skills, check out the Future of Functional Medicine Review Clinical Newsletter.

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.