What are prebiotics and who should take them?

One of the most interesting and promising research topics in IBS is the biome, the unique bacterial ecology in our belly which regulates our immune system, mood and digestive function.

While antibiotics have saved many lives, research is discovering that it doesn’t come without cost. Sometimes antibiotics are unavoidable. But it’s important to be cautious when taking them.

One course of antibiotics can disturb the biome for 16 months. The triple antibiotic therapy for H. pylori can lead to long lasting derangements in the composition of commensal (beneficial) flora for up to 4 years.

Probiotics have definitely risen in popularity and are even recommended by some doctors. However, there is a misunderstanding about what they do.

People think that probiotics can replace the good bacteria lost after a course of antibiotics. But that’s not true.

Once the bacterial strains are completely gone they are gone and can’t be replaced. But if there’s still a tiny bit left there’s hope to regrow it by feeding it.

The difference between probiotics and prebiotics

Probiotics are like tourists that pass through and spend money to improve the local economy. Their job is to support the immune system and create a good environment for local bacteria to thrive. They don’t move in and become citizens of the gut.

Prebiotics on the other hand, can help regrow beneficial bacteria by feeding them directly. Prebiotics are food for bacteria.

Some bacteria eat fiber while others eat starch. Prebiotics are a type of fiber that feeds beneficial bacteria. And different types of bacteria prefer different types of fiber.

There are many types of prebiotics. There are prebiotic fibers and prebiotics foods. The type of prebiotic you need to emphasize depends on what species of bacteria are lacking and need the most support.

Akkermansia, for example is a keystone strain that feeds other bacterial strains. I have written about it here.

Akkermansia likes cranberry and polyphenols (green tea, cocoa, red wine, blueberries).

Bacteroidetes a major bacterial phyla that like a prebiotic fiber called glucomannon. You can find glucomannon in pure aloe vera juice and konjac root. Shiratake noodles are made of konjac root and a great, low carb way to get your glucomannon.

Firmicutes is the other major bacterial phyla and it thrives on prebiotic like FOS and inulin.

Which prebiotics should you take?

Stool testing is the best way to figure out which bacteria strains or species are low/lacking and need support.

There are two options for testing. The GI Map will give you a breakdown of both the beneficial and pathogenic bacteria in your gut. It also provides information on how well you digest your food and if there are any pathogenic infections or gut permeability that are interfering with gut health and causing digestive symptoms.

You need to order the GI Map through a function medicine practitioner such as myself.

The other option is the Viome test, which anyone can order directly and also comes with food recommendations to help build up lacking strains.

If testing is not affordable or available another option is to buy a broad spectrum prebiotic supplement that you can throw in your smoothies, oatmeal, yogurt or soup.

I typically use this one with my clients. It has 12 different strains of prebiotics, including apple pectin which helps repair the intestinal lining. It contains the following prebiotics: fibregum tan acacia gum, CreaFibe Cellulose, guar gum, cranberry seed powder, carrot fiber, inulin, citrus fiber, apple pectin, glucomannan, psyllium husk, flax, prune, lactobacillus acidophilus La-14 (7.5 billion CFU/serving) and bifidobacteria longum (500 million CFU/serving). I typically take Two teaspoons a day.

This version comes with resistant starch added. Resistant starch feeds the bacteria in the large intestine that produce a short chain fatty acid called butyrate. Butyrate is extremely protective to gut lining and anti-inflammatory.

Who should not take probiotics

Since prebiotics are intended to support bacterial growth, people who have an overgrowth of bacteria in the small intestine (SIBO) should avoid prebiotic foods and supplements.

With SIBO the aim is to reduce bacterial overgrowth, and prebiotics do the opposite. For this reason, people with SIBO can react badly to both probiotics and prebiotics. For SIBO folks the usual digestive health advice of eating plenty of fiber and consuming fermented foods does not always apply. Most SIBO sufferers feel worse when they eat certain prebiotic foods.

Partially hydrolyzed guar gum is the only exception to this rule for people who have methane dominant SIBO only. This type of prebiotic fiber has been shown to reduce methane overgrowth.

What are prebiotic foods?

You can find some prebiotic foods on the high FODMAP food list. Onions, garlic, Jerusalem artichokes, leeks, asparagus, dandelion greens, apples jicama, and chicory root (found in many coffee substitutes).

Bananas are also rich in prebiotic but typically tolerable by most (but not all) people with SIBO.

One of the best ways to support the biome is to feed it as much diverse plant fibers as possible.

Roots and tubers (carrots, sweet potatoes, parsnips, rutabaga, celeriac) are particularly good for feeding and regrowing beneficial bacteria.

If you don’t have SIBO, eating a diet higher in FODMAPs (fermentable fibers and carbohydrates) will be restorative after a course of antibiotics.

Probiotic foods like yogurt, apple cider vinegar and sauerkraut are particularly great for supporting lactobacillus and also in lesser part, bifidobacteria species, which are important for reducing symptom of IBS.

Apples, artichokes, blueberries, almonds and pistachios, can all help your Bifidobacteria thrive.

Bifidobacteria helps digest dietary fiber and other complex carbs your body can’t digest on its own. It also helps prevent infection and produces vitamins and short chain fatty acids. Bifido help prevent infections from other bacteria such as E. coli by producing chemicals that prevent toxins from passing into the blood

Studies have shown that people with celiac disease, obesity, diabetes, allergic asthma and dermatitis all appear to have lower levels of Bifidobacteria in their intestines compared to healthy people