I’m really happy to see that some reader reports from Kimchi and Sauerkraut experimenters have started to pop up in the comments — people looking to repeat my L. plantarum & eczema experiment to see if they get similar results. And I’ve noticed that a distinct pattern has emerged from these reports: slow but noticeable improvement. Progress seems to be slower than mine. And for that reason, there’s a less definite causal link. When progress is slower, it’s much harder to connect it to a specific cause. After all, skin conditions progress in waves and are expected to both improve and worsen over time. But if the sauerkraut or kimchi that readers are consuming are the cause of this slow but noticeable improvement, then there is probably a good explanation for why my experiment produced quicker results, and thus more defined causality.
First, the reports. Reader Wilbur first reported that he, too, struggled with eczema in the past but that this winter was the first where he did not experience the symptoms. This happened to be the first winter that Wilbur was consuming sauerkraut and kimchi. Because Wilbur’s family members were also suffering from eczema, he decided to see if kimchi would help them:
I’ve only been able to work with one person, but I can say after 5 days of radish kimchi that the eczema in that person is very clearly receding and, in a few spots, is completely gone. From prior experience, it would not have done this on its own. This person also did not use any of the usual medical remedies.
Wilbur then followed up:
We’ve had an odd set of results. Patient 1 described above does indeed have receding eczema except that we noticed a new patch today. It’s possible we missed it before, but I don’t know how. Patient 2 has seen no effects from kimchi, and a new patch appeared today. I, on the other hand, have the best skin I’ve had in many years.
Reader Jason H. reports:
Day 5 – I’m eating 4-5 fork loads of the Farmhouse kraut per day and I believe that my knuckle has improved a small amount. I’m also keeping an eye on my ankles. They get dry and scaly in the winter and I never even thought of it being eczema related. There has been no improvement so far.
And reader Hielkje then reported:
For a while now a have one finger with eczema. Not very extreme, just a slightly more red, dryer en the lines more pronounced. Sometimes gaps arise, especially after cleaning. A few weeks ago, I had a small pimple underneath my finger. It itched for three weeks and very slowly disappeared. The day before I read this article, came another. Since I had sauerkraut in the fridge, I immediately started eating a couple of spoons. Raw of course. Now I have eaten it six out of the seven days. After the second day I saw the pimple became soft and smaller. The third day it was gone. Great, very happy. The skin of my finger has become a little more softer but is still dry. The color is now almost identical to my other fingers.
In my experiment, I noticed clear and dramatic results within 3 days. Why might this be? Well, the main difference between my experiment and the experiment of these readers is that, instead of consuming fermented foods, I instead took a probiotic pill that solely contained L. plantarum — the primary bacteria found in sauerkraut and kimchi. This pill contains 10 billion colony forming units of L. plantarum.
How does that compare to sauerkraut and kimchi? The data on this is extremely sparse, and considering how much fermented products can vary, we’ll have to assume that what we come up with is a very ballpark number. But from this sauerkraut production study, which I’ve repeatedly found to be one of the only studies that delves sufficiently into this question, we find that L. plantarum is a) the predominant bacterial species in sauerkraut; and b) is found to be at a concentration of 10 million CFU per ml of product. (I was also able to find some real-world confirmation on this product page, which states that based on independent lab tests, this brand of sauerkraut contains about 7.8 million CFU. So we really might not be that far off).
One standard serving of sauerkraut or kimchi comes out to about 4 tablespoons, which is about 60 ml of product. That is very close to my stated daily average of about four forkfuls. I assume readers are consuming around the same amount. We’ll also have to assume that, on average, sauerkraut and kimchi do not have widely divergent concentrations (sourness/acidity is a pretty decent measure of fermentation, and I’ve never noticed a big difference in sourness between the two). So given those numbers, here is the comparison:
Fermented food: 600 million CFU of L. plantarum / day
Probiotic capsule: 10 billion CFU of L. plantarum / day
Why does this make a difference? It’s quite likely that, as with any kind of intervention, to achieve a clinically significant effect you’d have to reach a specific concentration. When I first experienced remission from eczema in the winter, it was after consuming these fermented foods for months on an almost daily basis (I started consuming them in the spring of 2011). I had plenty of time to build up a concentration of L. plantarum in my body from these foods. From this study, we see that there was a significant difference between groups who were administered L. plantarum for 15 days and 30 days. And it found that it takes about 15 days after the discontinuation of L. plantarum administration for the bacteria to become undetected. So it does seem that administration has a cumulative effect, and slowly diminishes after consumption ends.
My experiment showed that it took three daily doses of 10 billion CFU to eradicate the eczema. At that rate, for those attempting the same with sauerkraut or kimchi, it would take 50 days to achieve similar results.
Now, I actually think it might not take quite that long — we have to allow for the fact that, regardless of reaching the right concentration, human skin can only heal so quickly. Perhaps I reached the required concentration on the second day. Maybe even the first. But regardless, these two different interventions will likely require different durations to achieve the same result.
This is also the reason I tend to favor interventions that will achieve results as quickly and dramatically as possible when engaging in personal experiments. That’s one of the reasons I decided to use a probiotic pill this time, rather than simply eating the fermented foods again. It’s really important to establish causality first — I can always go back to the fermented foods later. Delayed results can decrease motivation in continuing the experiment, and will result in some level of questioning. Now that I’ve established causality to a sufficient degree, I can freely go back to the fermented foods.