Wednesday, October 24, 2012

Kimchi on trial as eczema therapy. Not convinced

Those of you who are fans of probiotics, especially kimchi, will be thrilled to know that scientists recently reported the results of a trial testing kimchi-extracted bacteria as a treatment for eczema.

The researchers, led by Jihyun Kim at Sungkyunkwan University School of Medicine in Seoul, conducted a randomized, double-blind, placebo-controlled test of a strain of Lactobacillus plantarum in 118 eczema patients. L. plantarum is apparently a major species of bacteria found in Korean pickled cabbage, or kimchi, and a previous study showed that it had promise in a mouse model of eczema.

The idea behind probiotics is the hygiene hypothesis: in short, that being dirty is good for you (I'm pretty sure that most research shows that, if this is true, it holds only for kids during the first few years when their immune systems are developing). Proper balance of gut flora might tilt your immune system more toward a type 1 helper T cell-run operation rather than one dominated by type 2 Th cells, which are possibly over-represented in eczema patients. So: eat friendly bugs and reduce your chances of developing allergic disease.

The scientists split their subjects into a test group and a control group. From what I can tell they did as good a job as anyone could to make sure the results were not biased by expectation.

However, while they present their data openly in the paper, they claim it shows that L. plantarum clearly reduced symptoms of eczema, as measured by self-assessed quality of life as well as lab-quantified levels of immune cells and signaling molecules.

When I look at their data it says no such thing. In fact, it says that within experimental bounds, L. plantarum does nothing at all. I am surprised the journal editors allowed them to make those claims--but as always, maybe I'm missing something.

The trial was published in the journal Pediatric Allergy and Immunology, and paid for by the CJ Cheiljedang Corporation, which manufactures probiotic capsules of L. plantarum.

Thanks to reader K.M.O. for the tip.

2 comments:

  1. I tried the probiotics thing for a while. I noticed absolutely no change in my skin. So far, the only thing that does anything at all for me is cortisone, keeping a strict moisturizing regimen and avoiding dairy, wheat and eggs.

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  2. My impression from reading the scientific literature is that probiotics might be useful for eczema in the first two or three years of life. After that, sure, they might help your digestion and overall health, but they don't do anything specifically for eczema. However, a lot of people want to believe in probiotics, and they don't do any harm, so they're always going to be around as a benign placebo.

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