Prebiotics and Probiotics

A prebiotic is a soluble starch or fiber (oats, Metamucil/psyllium fiber, Miralax/propylene glycol). It is digested by our intestinal microbes and transformed into short chain fatty acids (SCFAs). SFCAs (butyric acid, propionic acid, valeric acid) are used for energy, maintenance, and repair in the colon.

Average fiber ingestion for our typical patient is 12 grams/day, but it should be 35-40 grams per day. Starchy root vegetables (sweet potatoes, yams, Russet or Yukon potatoes, carrots, parsnips, beets, turnips, rutabaga, butternut squash, winter squash, Jerusalem artichokes) are the best sources of soluble fiber.

Consuming prebiotics in diet helps create the gut flora needed to digest them and has many health benefits.

Some prebiotics also come in supplement form, and sometimes in the same supplement as the probiotics.

Prebiotics are contra-indicated on a FODMAP diet, which is one of the therapeutic diets that we use for people with irritable bowel syndrome. The reason is that prebiotic fibers feed all the microbes, and not only the good ones. Therefore, on a FODMAP diet, the idea is to starve all these pathogens.

Probiotics are specific microbes (mostly bacteria, but some yeast strains) that have known health benefits in humans.

When taking a probiotic supplement, it stays in your body 1-2 weeks. It makes B vitamins, vitamin K, it secretes antibiotics and anti-cancer substances and benefits your microbiome (gut microbes). Then, you will poop it out and it’s gone. Probiotics have temporary benefits, but they do not re-populate or re-colonize our colon. They refresh, renew and strengthen our colon function.

Who should be taking pre-biotics and pro-biotics? People who want to stay healthy, people with an auto-immune condition (which disrupts the microbiome and creates a leaky gut), people who take antibiotics (it could take generally 6 weeks to 3 months to re-balance your intestinal flora after a course of antibiotics). Other people who would benefit from probiotics are those with recurrent bladder infections, who get colds and flu all the time, vaginal yeast infections, athlete’s foot, and thrush.

There are no perfect guidelines for probiotic dosage, but in general 50-100 billion colony forming units per day are accepted dosages. We tend to dose them based on advanced nutritional laboratory evaluation. Probiotics are safe even in infants and pregnant women.

Most probiotic supplements are a combination of different strains, all beneficial for health.

A specific probiotic is an yeast, saccharomyces boulardii, related to bread yeast. It helps specifically people with yeast overgrowth. It can also help specifically when taking antibiotics, and also helps with diarrhea, even that caused by clostridium difficile. We recommend rotating different probiotic supplements that have different strains.

Sometimes, when first taking probiotics, some people feel worse as their intestinal microbes change. That is usually temporary and can be better with reducing the dosage.

Sometimes, probiotics produce a histamine (allergic) response. Using a low dose of just one strain of probiotic is sometimes helpful, for instance lactobacillus plantarum.

And if you are like me and have “pill-fatigue”, we found a delicious new way to consume probiotics. The Coconut Cult company makes great probiotic coconut yogurt, with 16 different probiotic strains and in 5 flavors. This food is natural, organic, and vegan, without fillers or thickeners. We ordered a bunch for our patients, but we ate the whole first batch ourselves (!). Not to worry, though, they have more! Check them out at

We hope this covers the basics of pre-biotics and probiotics. Please let us know if you have other questions.

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