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This is what you have been waiting for!  We had so much interest in the probiotic webinar in May that we ran out of time for all the questions.  Special thanks to Dr. Wendy Dahl for providing answers to questions asked in the webinar Enhancing Health and Wellness with Probiotics  The recording is posted and 1.0 CPEU offered for RDNs and NDTRS.  You can access this recording at .

Did I hear correctly that probiotics for antibiotic diarrhea is best for patients 65 or younger? 

Yes. In a review of the studies of probiotics and antibiotic-associated diarrhea (AAD) (Jafarnejad et al, 2016), researchers looked specifically at the elderly. They concluded that “adjunct probiotic administration is associated with a reduced risk of AAD in adults but not in elderly people [as a group].” No harm was found though and there may benefit to some individuals.

I read a study that showed that compared with taking probiotics post antibiotic therapy, the group that did not take any probiotics returned their microbiome to a pre-antibiotic state faster. This is counter to what I would imagine being the case, any thoughts on why that would be?  

I would need to read the paper that you are referring to. Please send my way by email. It may be possible that the probiotic somehow beneficially modulated the microbiota composition, i.e., the pre-antibiotic state was not necessarily ideal in all the individuals.

Do you know what is the mechanism to reduce depression? Is it brain-gut communication?

There are several mechanisms (or a combination) proposed by which the gut microbiota or probiotics might impact brain function, and thus depression, etc. It could be through metabolites (substances) produced by microbes that are absorbed into the blood and travel to the brain, such as short-chain fatty acids, etc. For example, some microbes can produce serotonin and other compounds (same as nerves produce), but it is unclear whether the microbe production of these metabolites changes the levels in the brain. Other ways that a probiotic may affect brain function might be through the immune system or the vagus nerve (which directly connects the brain and the gastrointestinal tract) – communication goes both ways through the vagus nerve, brain to gut and gut to brain.

Can I take stool softeners and laxatives without interfering with probiotics? 

I don’t think stool softeners would affect probiotics due to their lack of effect on transit (the time it takes for “food to waste” to move through the gut). However, laxatives may decrease what we call the “persistence” of probiotics. Our recent study showed that probiotics might be “washed out” in people with very fast transit times (e.g., diarrhea). If laxatives cause diarrhea, the probiotics may wash out quickly. One might need to ensure daily intake of a probiotic, maybe even more than once a day to maintain the probiotic and the effect.

What about generic, i.e., CVS? 

The probiotic brand, generic or otherwise, should label the probiotics it contains. It should state the genus (Bifidobacterium, Lactobacillus or other such as Saccharomyces), species (e.g., for Bifidobacteriumadolescentis, animalis, bifidum, breve and longum; For Lactobacillus….acidophilus, casei, fermentum, gasseri, johnsonii, paracasei, plantarum, rhamnosus) and strain for most (often a combination of letters and a number) (e.g.,Lactobacillus johnsonii N6.2) and the number of live organisms or viable cells (at least 1 billion). Buying from a store that has fast turnover is good too so you can be quite sure that the probiotic has not been sitting on the shelf for months (and mostly dead).

Does alkaline water have any effect on probiotics? 

There is very little research on how foods and beverages we consume affect probiotic survival. Consuming probiotics with food is thought to protect them from stomach acid. Antacids neutralize stomach acid, but I don’t think there is any research looking at whether alkaline water would affect probiotic survival.

Back to your comment that yogurt is NOT all probiotic. For the everyday person, client, yogurt is an easy and desirable food to recommend. What do RDNs do now to recommend an easy-to-find and flavorful probiotic food? 

As you are aware, yogurt is a healthful food even if it does not contain a tested probiotic. If a consumer is looking for a specific health effect for a probiotic, they can look for a product that contains more than just the fermentation organisms (L. bulgaricus and S. thermophilus), but one or more Bifidobacterium or other Lactobacillus spp. If the consumer is after a very specific health effect, then look for products that list more than just genus (Bifidobacterium, Lactobacillus or other) but also the species name (e.g., for Bifidobacteriumadolescentis, animalis, bifidum, breve and longum; For Lactobacillus….acidophilus, casei, fermentum, gasseri, johnsonii, paracasei, plantarum, rhamnosus) and a strain indentify (often letters and/or a number). One example is Bifidobacterium lactis DN 173-010 but there are others with demonstrated probiotic health benefits.

How does greek yogurt, with active cultures figure in? 

Greek yogurt is just made a bit differently and is higher in protein. It still goes through the general fermentation process with the fermentation microbes such as L. bulgaricus and S. thermophilus. Greek yogurt can be with or without specific probiotics.

Are there times when probiotics are contraindicated and could cause harm? if so, what are some examples? 

Probiotics have a long history of safe use and are generally considered safe for most populations. There are “theoretical risks” and a few case reports of systemic infections and potential side effects. Allergy is also a possible risk given some are grown on a media containing milk. It is generally suggested that individuals with immune-compromising conditions should consult their physician prior to taking probiotics.