L. Reuteri Is Your Friend

A once common microbe in the human microbiome is L. reuteri (Limosilactobacillus reuteri; formerly known as Lactobacillus reuteri). It’s been central to mammalian evolution. But in modern humans, it’s in decline because of widespread use of antibiotics and farm chemicals, in the latter case specifically pesticides like glyphosate that has actually been patented as an antibiotic. “Recent studies have shown that low-level chronic dietary exposure to pesticides can affect the human gut microbiota” (J. Gama, et al, Chronic Effects of Dietary Pesticides on the Gut Microbiome and Neurodevelopment).

This is problematic since L. reuteri is such an important microbe for human health, demonstrating numerous health benefits. You’ll see wide array of scientific studies, articles, and videos that come up if you look at the Google results about several scientifically-supported strains of L. reuteri: DSM 17938, ATCC PTA 6475, ATCC PTA 5289, RD830-FR, and SD-LRE2-IT. It’s gotten a lot of attention in the alternative diet community. Dr. William Davis, of Wheat Belly fame, recommends making one’s own cultured dairy. There are many cheap yogurt makers, and some models of the Instant Pot have a yogurt making function.

In the past, humans could replenish microbes from food and environmental exposure. But commercial brands of probiotic foods like yogurt, kefir, and kombucha tend to lack L. reuteri; and, besides, they rarely contain high amounts of any microbe because they typically don’t let them culture long enough. And of course, for most of us, our environments and bodies have been hygienically cleansed. It’s part of the hygiene hypothesis, seemingly underlying the rise of many diseases, especially related to allergies and autoimmunity. This is unsurprising. After all, most of the genetics in the human body originate in non-human organisms.

That is why many people turn to probiotic supplements. There are several high quality and highly recommended products, some for general purposes and others more specific: BioGaia Gastrus, BioGaia Prodentis, and Seed DS-01 Daily Synbiotic (there are other products, but most companies don’t list the strains, CFUs, scientific research, and other info). These probiotic products can also be used to make one’s own cultured foods, which is actually more effective. Every three hours, the number of microbes doubles. So, the microbe count grows quite large by the time a standard 36 hour culture is finished.

According to Dr. Davis, over 90% of individuals in modern industrialized populations have entirely lost L. reuteri. In general, the contemporary microbiome, specifically in the West, is smaller and less diverse than that of traditional people. About L. reuteri specifically, it not only improves the health of gut, skin, immunity, joints, muscles, and much else. More interestingly, it helps the body to release the hormone oxytocin, the love molecule. Research has shown that, once reintroduced, human subjects feel calmer and more relaxed, kinder and more empathetic, closer and more understanding; while sleep and general wellbeing is improved.

Dr. Davis speculates that the loss of L. reuteri might be a causal factor in the psycho-social problems rampant in our society. And if so, he asks if reintroducing it might undo the damage. That fits into our own thinking and that of many others. There was a ketogenic study done on diabetic kids back in the 1940s or 1950s where the researchers noted that, besides health improvements, there were also behavioral improvements. Before that in the 1930s, Dr. Weston A Price observed that what he called moral health (happiness, friendliness, and pro-social behavior) was closely associated with physical health.

Directly relevant to our topic here, one might note that the traditional communities Dr. Price was looking at were eating probiotic foods and were not yet exposed to antibiotics, antimicrobials, farm chemicals, and industrial toxins. This is further corroborated with a wide array of evidence in Alan C. Logan and Susan L Prescott’s book The Secret Life of Your Microbiome: Why Nature and Biodiversity are Essential to Health and Happiness. It’s an intuitive view to take, that humans would be healthiest and act the healthiest when living in the optimally healthy conditions under which humans evolved.

9 thoughts on “L. Reuteri Is Your Friend

    • We bought the BioGaia product Gastrus. It has the two strains of L. reuteri that Dr. William Davis recommends. We’ll be making yogurt from it, as soon as we figure out how. Our Instant Pot is a model with the yogurt making function. The main issue is figuring out how to maintain it at body temperature. The typical strain used for yogurt cultures at a higher temperature.

      Also, we decided to get Seed DS-01 Daily Synbiotic, also mentioned above. It is a balanced and broad-spectrum probiotic that includes a different strain of L. reuteri, but many other varieties of microbes. It gets a lot of positive reviews in the alternative health community. We appreciate their scientific approach, in offering supporting evidence for the purpose of each strain. And most importantly, their product appears to be effective.

      In looking around, these seemed to be two of the best probiotic companies. In recent years, we’ve done many other changes, in diet, exercise, and lifestyle. But we haven’t yet tried high quality probiotics. Years ago, our main health issues, excess fat and chronic depression, were resolved. But we still have some lingering issues, including some aftereffects (e.g., irritability) carried over from decades of depression — maybe we could use an oxytocin boost.

      The last point we made in this post is closest to our heart. We were glad to see Dr. Davis brought it up in some of his videos. We probably have mentioned it to you before. But here we left out the ideological angle. We’d love to see more research along these lines. It’s scientifically known that unhealthy conditions (pathogen exposure, parasite load, stress, etc) increases social conservatism and right-wing authoritarianism. So, would reintroducing something like L. reuteri increase the rate, instead, of social liberalism and left-wing egalitarianism?

    • By the way, what action have you now taken in regards to L. reuteri? Have you used probiotics in the past? We have off and on over the years, but it’s always been something we picked up at a local store, and so probably nothing as high of quality. This is the first time we got more serious about looking into what’s available on the broader market.

      We will be doing our own experimentation, as is our wont. Though having lost some initial enthusiasm about the yogurt, we still plan on trying it out and hoping for the best. But we’ll also be taking the Seed synbiotic (prebiotic + probiotic). After mentioning it to our oldest friend, he decided to try out Seed as well. He too was impressed by what he read about it.

      It’s quite interesting, once you start digging into it. There is a lot more info about it these days, for one thing, and that is what is now drawing me into it. Like other areas of research, it seems the field is advancing quite a bit and quickly. All in all, one can sense how we are on the verge of revolutionary changes in the understanding of many aspects of human health.

      That last part is what captures our curiosity the most, as we already mentioned. What if so much of what we think of as personality, thinking style, character, morality, culture, and ideology is most fundamentally about health, individual and public, private and shared; in terms of genetics, epigenetics, and environment with the probiotic angle including all three areas?

      Whatever experiments you do with probiotics, we hope you come back and let us know about it. We can compare notes. If we (the blogger) have more info, thoughts, and observations on the matter, we’ll consider writing another post for an update. This above writing was our preliminary thoughts, as we begin our own experiments. We’ll see about getting a yogurt fermenting this weekend. And our order of Seed should be coming in soon.

  1. As a side note, we’ve continued to do research on the topic. One concern came up in a Reddit discussion, about making yogurt with L. reuteri. It evolved to grow in the mammalian body, not fermented in a container of dairy. It needs the conditions of a body to protect it from competing microbes.

    It doesn’t compete well because it grows relatively slowly. But under normal conditions, in being introduced to babies, that slow growth is fine over a lifetime, as long as there aren’t antibiotic exposures. In a ferment, though, a contaminating microbe is likely to quickly outgrow it. And a sterile environment is about impossible outside of a laboratory. That is why the BioGaia company warns against trying to make a yogurt with it. Some others agree with the reasons given. But it’s hard to know as a non-expert.

    It’s not necessarily so much the worry of contaminants, as wild microbes can have health benefits as well. Wild fermentation is a common practice, after all. But it means that one can’t determine how much L. reuteri is in the final product, possibly no where near as much as claimed by Dr. William Davis. And with each batch made with the last, contaminating bacteria could increasingly take over. Apparently, no testing has been done on homemade L. reuteri yogurt. All that Dr. Davis says is that, when looked at under a microscope, he sees L. reuteri. That is as expected. That still doesn’t answer the question of the bacterial count (CFUs).

    That said, it doesn’t necessarily follow that yogurt can’t or shouldn’t be made with L. reuteri. Even with contaminants, the desired strain will grow to some extent, maybe depending on how much fermentation medium one is using. Dr. Davis, for example, recommends adding inulin. But the additional fermentation medium will first and foremost feed the invasive bacteria, and so it might not actually increase L. reuteri beyond what would otherwise happen. The whole point is that fermentation drastically increases the number. Is that true or not? If not, one might be better off just taking the tablets straight.

    Still, L. reuteri will proliferate as well, if to a lesser degree, unless there is some other factor that interferes. Or that would probably be the case, as one might speculate, in the first batch and maybe the batches immediately following. But Dr. Davis might be incorrect that endless batches can be made from the last with no degeneration with foreign bacterial takeover. Many people have observed that the consistency improves or worsens with later batches, and that is likely an indicator of contaminants.

    One commenter in another Reddit discussion stated that they use the BioGaia tablets for 3-4 or slightly more batches, and then they start over going back to the tablets again. That seems like a wiser and more cautious approach, if one insists on making yogurt with it. But we’re undecided at this point, feeling less confident than we did originally. One could, of course, split the difference by alternating between taking the tablets and making yogurt from them.

    Importantly, the issue is not so much that L. reuteri yogurt can’t be made but under what conditions can it be effectively and safely produced. The BioGaia company made their own yogurt product for a time, although it apparently was only available in Japan. Sales, however, dropped; maybe because of Covid-19 shutdowns. That’s too bad. If it was available in a local store or otherwise easily purchased, many people would go with that option, not only for the insurance of quality but also simple convenience.

    Contrasted to homemade L. reuteri yogurt, the thing is BioGaia would’ve been producing their yogurt in the same sterile conditions as their other products, along with testing it regularly to ensure content and quality. That can’t be replicated in a home kitchen. But it’s hard to dismiss all of the positive testimonials of those who have followed Dr. Davis’ directions in making their own L. reuteri yogurt. Maybe we will experiment. It’s just not clear what we could ever determine through experimentation. We don’t doubt we can make yogurt. It’s just the whole point is to get as high amount of L. reuteri as possible. Without sending our batches out to a lab for testing, we could never know what we’re getting. That is disappointing.


    “Is it possible to make yoghurt by adding BioGaia’s probiotic L. reuteri strains to milk?

    “It cannot be recommended to use BioGaia’s probiotic Limosilactobacillus reuteri (formerly known as Lactobacillus reuteri) strains for yoghurt production. The BioGaia L. reuteri strains are probiotic bacteria of human origin that thrives in the human GI tract and exerts its effect there. It does not produce the right compounds that turn milk into yoghurt. They do not multiply properly and do not give texture or flavor to the product when fermented in any type of food.

    “BioGaia cannot take responsibility for the safety of “yoghurt products” produced at home with our probiotic strains.”

    • Here is an update. We got to talking with someone who seems to have experience and understanding. He further explained about the process of making L. reuteri yogurt. It might be presumed that the other strain he is referring to is L. reuteri DSM 17938, with both strains included in the BioGaia Gastrus product. With the two combined, it sounds like contamination is less of a concern. Below is what he said:

      “The original blend used by Dr. Davis actually had a another communal type of Reuteri that seemed to protect against foreign invasion while enhancing proliferation of LR6475. When just using LR6475 alone you just want to make sure to flood it with starting counts around 100-200 billion, in which even just the sheer lactic acid production is enough to claim it territory in full.

      “That and maintaining consistent 100 degree temps during the fermentation helps not only for the growth, but also to keep a majority of other things out.

      “Still I definitely try to err on the side of caution and abide by the basics of fermentation by making “clean” batches after a few— because without proper equipment and testing who knows what potential hitchhikers you can end up with during storage that can proliferate to a point of causing issues over multiple generations.”

    • We started a discussion on the Fermentation subreddit. Two of the commenters were kind of aggressive, actually; or rather some combination of haughty and condescending. We ended up having to put one of them back in his or her place, in defending the utility of culturing L. reuteri in dairy; which was ironic as the topic of discussion was how to do so without dairy. If you look at the following comment thread, you’ll see the info dump where we summarized the dairy issue and shared numerous scientific articles.

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