Science Says Sunday – Probiotics

Instagram, like Facebook, will often remind you of the pictures you posted on your feed years ago. This one is from 2014 when I attended the See Jane Write bloggers conference organized by the one and only Javacia Harris Bowser. What a fun time in blogging that was! I was a newbie, talking all things sartorial and very much still finding my footing in academia.

2014 is when I started my faculty position, and hadn’t yet found the confidence to share all things science. I felt more comfortable talking about fashion and lifestyle, how they related to life in academia, and some about my journey as a woman and person of color in academia as well.

I’m glad that this blog’s focus has evolved and I’m now talking about public health and health topics generally, with sprinkles of fashion and lifestyle here and there. 🙂

Today, I’m covering probiotics because I was recently introduced to the scientific work of Dr. Patricia Hibberd, Infectious Disease specialist and Chair of Global Health at Boston University. Together with information I’ve read, here are some points that you should consider if you are or want to take probiotics. Some, even I found surprising!

  • Is there convincing evidence that commercially available probiotics have been found to be beneficial to
    • treat or prevent the diarrhea after taking antibiotics?
      • No
    • decrease allergies?
      • No
    • treat irritable bowel syndrome
      • No
    • improve gut health in babies (via baby food and baby formula?)
      • No
  • Is this better than that?
    • Cold probiotics vs room temp
      • yes; and you’re not consuming good bacteria just because you’re eating yogurt. All yogurts with live bacteria contain Lactobacillus bulgaricus and Streptococcus thermophilus, but some manufacturers add other probiotic bacteria after pasteurization, such as L. acidophilusL. bulgaricusL. rhamnosus and L. casei.
    • Probiotics vs medication
      • probably not. There is no evidence that taking a probiotic over medication for any illness is proven more effective than the medication intended to treat the problem.
    • Prebiotics vs probiotics
      • apparently not mutually exclusive. In order for probiotics to be most effective, you need to have good representation of prebiotics in your daily nutrition. What does that mean?
        • “Prebiotics are specialized plant fibers. They act like fertilizers that stimulate the growth of healthy bacteria in the gut. Prebiotics are found in many fruits and vegetables, especially those that contain complex carbohydrates, such as fiber and resistant starch. These carbs aren’t digestible by your body, so they pass through the digestive system to become food for the bacteria and other microbes.”

Even I, a scientist, was convinced that taking probiotics while taking antibiotics would help prevent diarrhea. Wow!

Interestingly, two other scientists in the field – Eran Elinav and Eran Segal found at Israel’s Weizmann Institute of Science – carefully studied the effects of probiotics on the gut and collected samples from a small group of volunteers. What did they find:

Strikingly, in about half the people, the probiotics went in and went right back out. In the other half, they did appear to stay in the gut:

“Although all of our probiotic-consuming volunteers showed probiotics in their stool, only some of them showed them in their gut, which is where they need to be,” says Segal. “If some people resist and only some people permit them, the benefits of the standard probiotics we all take can’t be as universal as we once thought. These results highlight the role of the gut microbiome in driving very specific clinical differences between people.”

Their second study “questioned whether patients should be taking probiotics to counter the effects of antibiotics, as they are often told to do in order to repopulate the gut microbiota after it’s cleared by antibiotic treatment. “

“Contrary to the current dogma that probiotics are harmless and benefit everyone, these results reveal a new potential adverse side effect of probiotic use with antibiotics that might even bring long-term consequences,” Elinav says. “In contrast, replenishing the gut with one’s own microbes is a personalized mother-nature-designed treatment that led to a full reversal of the antibiotics’ effects.”

So, what does this mean?

Well, I think it means you’re probably better off eating a healthy diet and saving that money you’re spending on off-the-shelf probiotics, on something else! Sure, there seems to be no harm in consuming yogurt with live cultures, for example. But there is certainly greater benefit to eating – as my registered dietician colleague, Dr. Amanda Willig, says – other gut-health foods like “beans, oatmeal, and vegetables”.

Until we have better studies and better understand the gut biota, continue to learn about the products being thrown your way, but for now save that extra money for a rainy day.


  1. Niv Zmora, Gili Zilberman-Schapira, Jotham Suez, Uria Mor, Mally Dori-Bachash, Stavros Bashiardes, Eran Kotler, Maya Zur, Dana Regev-Lehavi, Rotem Ben-Zeev Brik, Sara Federici, Yotam Cohen, Raquel Linevsky, Daphna Rothschild, Andreas E. Moor, Shani Ben-Moshe, Alon Harmelin, Shalev Itzkovitz, Nitsan Maharshak, Oren Shibolet, Hagit Shapiro, Meirav Pevsner-Fischer, Itai Sharon, Zamir Halpern, Eran Segal, Eran Elinav. Personalized Gut Mucosal Colonization Resistance to Empiric Probiotics Is Associated with Unique Host and Microbiome FeaturesCell, 2018; 174 (6): 1388 DOI: 10.1016/j.cell.2018.08.041
  2. Jotham Suez, Niv Zmora, Gili Zilberman-Schapira, Uria Mor, Mally Dori-Bachash, Stavros Bashiardes, Maya Zur, Dana Regev-Lehavi, Rotem Ben-Zeev Brik, Sara Federici, Max Horn, Yotam Cohen, Andreas E. Moor, David Zeevi, Tal Korem, Eran Kotler, Alon Harmelin, Shalev Itzkovitz, Nitsan Maharshak, Oren Shibolet, Meirav Pevsner-Fischer, Hagit Shapiro, Itai Sharon, Zamir Halpern, Eran Segal, Eran Elinav. Post-Antibiotic Gut Mucosal Microbiome Reconstitution Is Impaired by Probiotics and Improved by Autologous FMTCell, 2018; 174 (6): 1406 DOI: 10.1016/j.cell.2018.08.047

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