A quick catch up for anyone who is just tuning in:
Recently, I discovered that L. plantarum — the dominant bacterial strain in fermented plant foods like kimchi and sauerkraut — cures my hand eczema. I initially discovered this by noticing that I hadn’t experienced any eczema in the past two years, during which I consumed these foods on a near daily basis. And I then noticed that once I stopped consuming them last fall, my eczema returned. I hypothesized that not only was it these foods that kept the eczema away, but that it was specifically the probiotic bacteria that was creating the effect, because probiotic bacteria are known to primarily act through immune system modulation. And eczema is an allergy-related disease that is a product of an abnormal immune system response. So to test this hypothesis, I obtained a probiotic supplement containing a pure, isolated form of L. plantarum. Within three days of taking the supplement, my eczema had completely cleared.
Since then, multiple reports from readers of this blog (and elsewhere) have tried the experiment and replicated the results. And they have worked for other immune/allergy-related conditions as well, which was something I also hypothesized in my original report.
As you can imagine, since then I’ve been extremely interested in L. plantarum. Here’s why:
- Anything that can have this kind of effect on the human body must hold some major significance for general human health.
- Fermented foods have been a part of the human diet for a very long time, and are found throughout almost every culture. Humans are very likely adapted to eating them, which means the bacteria in fermented foods are important for human health.
- Fermented foods, for the most part, fall into two categories: vegetables and dairy. Because L. plantarum is the dominant bacterial strain in fermented plant foods, this means that L. plantarum would account for a very significant proportion of the health benefit derived from fermented foods.
And it’s that last point that my mind has been focused on lately. I’ve been pretty satisfied with the explanation that L. plantarum must be important because it’s so dominant in fermented vegetables, which probably make up the majority of fermented foods (milk is just one food, but there are many types of plant foods you can ferment). But I haven’t been completely satisfied.
You see, I also very regularly consume fermented dairy, in the form of yogurt. But I never found yogurt to have any effect on my eczema. I’ll consume it for a while, stop for a while, and nothing. And it’s also the case that L. plantarum is not in yogurt. But fermented dairy must be important to human health as well. I guess L. plantarum can’t really explain its importance.
Or can it?
One thing I’ve known is that, while L. plantarum is never in any yogurt I’ve ever come across, it is found pretty often in kefir. Yogurt, on the other hand, has probably gone through quite an evolution in the past hundred years as it’s become a much more ubiquitous, mass produced food. Today, for a manufacturer to be able to call its fermented dairy product “yogurt,” it needs to contain just two bacterial species: S. thermophilus and L. bulgaricus. Whether this has anything to do with what constitues the ancient and ancestral formulation of yogurt, I do not know. But I very much doubt it.
Kefir production, on the other hand, very likely maintains much more of its traditional “ancestralness.” It isn’t as widely consumed, and can be considered much more of an artisanal food product. It is most often produced through the use of traditional kefir grains, which likely maintain a bacterial profile that is much closer to the kefir that’s been consumed for centuries. Kefir is always MUCH more diverse in its bacterial profile. Here is an example of the content of one widely available kefir grain starter set. You’ll notice it is much more diverse than your average yogurt product, and it contains L. plantarum.
And here is a study of traditional Tibetan kefir grains. Guess what bacterial species was isolated from them? L. plantarum.
Is it possible that the traditional yogurt consumed by ancient cultures also contained L. plantarum at one point? Kefir is known to have originated in the Caucasus. But yogurt, too, is known to have a strong connection to the Caucasus region, and perhaps originated there as well. Wouldn’t it be awfully likely that the traditional formulation of yogurt would contain a bacterial profile that is much more similar to kefir, and generally more diverse than what you find today on store shelves?
But there’s more.
I just came across this study (thanks Dr. BG!) that analyzes the fermented milk consumed by the Maasai tribe of Kenya. The Maasai are a beloved object of study by the paleo/ancestral health community, probably owing to the fact that they maintain a very traditional, ancestral way of life, and because they show that you can consume a ton of milk, blood, and meat all day and stay pretty healthy.
For the Maasai, milk is an extremely important food source. Probably the most important. And the majority of it is consumed in fermented form. And guess what bacterial species was found to predominate in the Maasai’s fermented milk:
Lactobacillus plantarum was the major species among the lactic acid bacterial strains isolated from traditional fermented milk of the Maasai in Kenya.
Or how about this: Dadiah is a traditional fermented buffalo milk drink consumed by the Minangkabau tribe of Indonesia. In other words, another excellent way to see what traditional dairy fermentation really looks like.
And once again, we find L. plantarum to be a major component of this product. Not only that, but when analyzed, it was found to be the bacterial strain that had the greatest anti-colonization effect on pathogens in the fermented drink:
The most adhesive Lactobacillus plantarum strain was IS-10506, with 9.8% adhesion. […] All tested LAB strains displaced and inhibited pathogen adhesion, but the results were strain-specific and dependent on time and pathogen strains. In general, L. plantarum IS-10506 showed the best ability against pathogen adhesion.
As you can see, not only did the traditional fermented drink contain L. plantarum, but when compared to other Lactic Acid bacterial strains, it was shown to be the one with the strongest impact on host health.
Which brings us to the second part of our exploration. I think we’ve established a pretty good anthropological case for L. plantarum’s importance for human health. But what about some hard, scientific data? Well, that last study on Dadiah isn’t bad. And my own experience with eczema is pretty darn good proof, too. But are there any other studies comparing L. plantarum’s immune modulation abilities to other bacterial strains? Would I even be asking that question if there weren’t any!?
Here’s an interesting one: researchers took a look at which bacterial strain had the best ability to reduce an allergic reaction to soy. They fermented soy with various bacterial strains, including Bacillus subtilis and, of course, L. plantarum. The use of B. subtilis is especially interesting, because it is the traditional bacteria used to ferment soy into Japanese Natto. The results: fermentation by all bacteria reduced allergy response significantly, but L. plantarum did the best:
L. plantarum fermented soy flour showed the highest reduction in IgE immunoreactivity (96-99%) depending upon the sensitivity of the plasma used.
But here’s an even better one. It isn’t even about L. plantarum. It’s about Bifidobacterium infantis. The study examined B. infantis’s ability to protect the gastrointestinal barrier through its immune modulating effects. But before it did so, it first did a comparison among bacterial strains to see which had the strongest effect. The one with the strongest effect was the one chosen to be further examined. B. infantis was the winner, so that’s the one that was chosen to study further.
As you can see, B. infantis came in first. And Bifidobacterium breve came in second. Third place: L. plantarum! Why does this vindicate what we’ve been saying? Because out of the three, only L. plantarum is a probiotic bacteria found in fermented foods. The other two are bifidobacteria — they are the commensal bacteria that reside in the human body. Of course these would show the strongest effect! B. infantis, specifically, is the dominant strain of commensal bacteria found in human infants. This is like comparing the importance of a micronutrient to a human organ. Exogenously consumed probiotic bacteria like L. plantarum can be thought of as a very important nutrient like, say, Vitamin D. But your commensal microbiota are a part of you. So sure, Vitamin D is important for human health. But you know what’s even more essential? Your spleen.
So from this graph, on the specific, narrow measures that this study uses, we see that L. plantarum is indeed a major player in human host health. And probably THE major player when it comes to fermented food consumption. And it’s quite likely that this study alone doesn’t get at the entire unique nature and capabilities of L. plantarum.
And now a final, meta note to end this post. As you can see, both anthropology and scientific data are vital tools to figure out the human health puzzle. This post, and this blog in general, are a pretty good testament to that, I hope. But in the end, when it comes to practical matters of health, I have to vouch for the superiority of anthropology, for a very simple reason: despite what many “experts” would have you believe, there is so much more we don’t know than we do know. When it comes to human health, anthropology is a map of the unknown.
Take my eczema example, for instance. I consumed fermented foods for over two years. Why? Not because I had any scientific proof that they would help me. I didn’t even know how, exactly, they could improve my health. I simply observed that they seemed to be an immensely important part of traditional human food consumption. So I took it on faith. For a while. (It also helps that I grew to like them.)
But I’m also a pretty skeptical person. After a while, I started to wonder if there really was any benefit. So I stopped consuming them. And that’s how I made my discovery. The dots were all there, of course — the fact that eczema is an immune condition, that probiotic bacteria modulate the immune system. Even studies showing L. plantarum treating eczema in mice and humans. But seeing the dots and connecting them is easy in hindsight (in fact, that’s how most experts make their livings, and then pretend it was foresight).
Anthropology was the map. It allowed me to follow a healthful trail without seeing the dots. And then a healthy dose of skepticism and personal experimentation turned on all the lights.
In conclusion: eat your damn kimchi!