I’ve got an exciting personal experiment to report on.
Some time in the past decade, I developed a very troubling case of hand eczema that is mostly triggered by cold, dry weather in the fall and winter. It can also flare up when I do a lot of cleaning — when my hands are exposed to a lot of water and soap, which are very drying. It results in patches of painful, red, itchy, inflamed, dry skin covering most of my hands. If you know anything about eczema — also referred to as atopic dermatitis — you know that it’s very different from your run of the mill “dry skin.” In fact it’s a completely different thing — it’s an inflammatory byproduct of an overactive/abnormal immune response. Like an allergy, but on your hands. In my case, I’ve determined that a certain level of dryness is required to trigger this response — hence the weather and cleaning triggers. The dryness allows something in the environment — things that should usually be benign like dust or pollen — to trigger the overactive response.
I initially treated this the same way most people do — go to a dermatologist and have them prescribe a steroid-based cream. But as I learned more about what eczema actually is, I decided this was an absurd way to treat it — essentially nuking your skin with steroids, which have nothing at all to do with the pathogenesis of eczema, to make it simply stop producing more skin. At best it treated the symptoms, and it had side effects that didn’t seem very worth it (is there anything creepier than “skin thinning”? It’s like out of a horror movie). Given that dermatologists have a monopoly on prescribing steroid creams, I figured they were probably more useful to them than they were to me. So I just lived with it.
But a funny thing happened. Over the past couple of years, it stopped happening. But I didn’t actually realize it stopped happening until this fall, when it came back. It was quite a shock — I had completely forgotten about it. But as soon as the weather began to turn cold and dry, it hit hard. Nothing had significantly changed about my environment this year compared to the past few. So then I started to think about diet. But I had not made any dietary changes in the past year or two. And then it occurred to me — I actually did, and very recently. In September I decided to stop consuming a few staple fermented/probiotic foods that I have steadily consumed for the past couple of years — sauerkraut, kimchi, and kombucha. The kombucha was much less frequent — probably a few times a month. But sauerkraut or kimchi were consumed almost daily. I decided to stop them all to see if it made any real difference in how I felt. And for a while I didn’t notice anything. But then fall came, and so did the dry, cold weather. And then the eczema. And I also realized that the last time I had eczema was the winter right before I began regularly consuming these foods. Was there a connection?
I decided to focus on kimchi and sauerkraut, as I consumed them much more frequently than kombucha. And I already knew what the “active ingredient” in these foods would be — fermented vegetables like sauerkraut and kim chi are dominated by the bacterial species Lactobacillus plantarum. In addition to this, I knew that, unlike the commensal bacteria that take up residence in our gut, the primary mechanism of action that exogenous bacteria from fermented foods have in the human body is immune system modulation as they pass through. And again, eczema is a product of abnormal immune response. If sauerkraut & kimchi were responsible for the abatement in my eczema, then it was the L. plantarum and its immunomodulating effects.
Well, after multiple flares over the past few months, I finally got around to testing this hypothesis out.
I searched around and was able to find a probiotic supplement that was solely composed of isolated L. plantarum (it’s marketed as a digestive aid, but I ignored that). I then waited for my eczema to flare up again. As soon as it did, I began taking the L. plantarum. Within three days, the eczema had completely disappeared. This would usually be when the eczema actually gets worse. It usually has about a 2 week cycle before the active inflammation completely subsides. I’ve never seen it disappear like this. Usually at this point, hand washing would be painful and exacerbate it. Now I could hand wash with abandon. Even more amazing: I was able to walk around outside during a particularly cold spell without gloves, and did not have any exacerbation or return of the symptoms whatsoever. Being able to do these things three days into a flare up is unheard of. My hands now feel completely impervious to the triggers. Something has clearly interrupted the inflammatory response.
Following this discovery, I searched around and actually found a tiny handful of studies that support the effect of L. plantarum on eczema:
- Two separate studies showed L. plantarum inhibiting house-dust-mite-induced eczema in mice.
- Another study found a similar effect — L. plantarum inhibited allergic reaction and histamine-induced scratching (which is a hallmark symptom of eczema) in mice. It concluded that L. plantarum “may improve allergic diseases, such as anaphylaxis, atopic dermatitis, rhinitis, and pruritus…”
- L. plantarum was successfully used as a vaccine against dust mite allergy in mice.
- And based on the promising results in these mouse studies, a human study was done to see if L. plantarum had an effect. It did. The study looked at 118 children with eczema, and found that in the group given L. plantarum, the bacteria was seen to have a beneficial effect.
In all of these studies, L. plantarum led to inhibition of allergy & dermatitis through immunologic alteration. Exactly as I predicted would happen to me. I did not know these studies existed until after my own experiment. The fact that they corroborate my own experience is quite compelling.
If anyone else out there has this issue, consider giving this a try and reporting back. I’m really curious to see if it works for other people. I also think it must hold some potential for alleviating environmental allergies. I plan to post an update looking more deeply into how L. plantarum is having this effect, as I think there is a lot more to be learned from this.
And a final note. This all goes to show that probiotics/fermented foods certainly do have their place in gut health, but in a very different way than fermentable fiber consumption. Contrary to what many believe, probiotics and fermented foods will not significantly alter the bacterial composition of your microbiome. As these studies indicate, and my experience shows, the bacteria and their beneficial effects are undetected once consumption ceases.
Which makes sense.
As I said, the main mechanism of action for exogenous bacteria is through immune modulation as they pass through — a fundamental principle of the “Hygiene Hypothesis,” which contends that humans evolved to have regular exposure to bacteria from foods, soil, animals, and the environment to the extent that these bacteria became a fundamental part of our immune system. They don’t take up residence, they are merely tourists exploring a vast jungle. But like any deep pocketed traveler, they have beneficial effects as they pass through. A steady, constant exposure is the key.
In the case of our resident, commensal gut bacteria, it’s a very different ballgame. In this instance, we’re looking to modulate a rainforest teeming with flora numbering over 100 trillion. Do you really think parachuting in a few billion foreign flora, who don’t even consider this their home, is going to significantly affect this ecosystem? Or does it make more sense to, say, make it rain 50% more in a given month?
Want to alter your microbiome? Make it rain. Consume plant fiber.
But if you have an annoying case of eczema, you might want to host a few more jungle tours.