Intake of yogurt containing L. lactis improves atopic dermatitis – Japan trial
Conducted by researchers from the Fukushima Medical University, the study was funded by The Fukushima Industry Support Fund and used a probiotic yogurt produced by Tohoku Kyodo Milk Industry.
The yogurt studied was fermented with five probiotic strains, namely S. thermophilus ST-20 strain, L. bulgaricus LB-12 strain, L. acidophilus La-5 strain, B. lactis Bb-12 strain, and L. lactis 11/19-B1.
According to the findings published in Nutrients, the consumption of the yogurt had alleviated AD symptoms, with L. lactis 11/19-B1 identified as the strain responsible for the improvement.
In the study, 18 AD patients between two to 15 years old were recruited and had to consume 80g of the yogurt daily for eight weeks.
During the study, they could continue with their AD treatment, including topical steroids and medicines, but were told not to eat foods containing probiotics.
An AD severity assessment and blood sampling were conducted every four weeks till the end of the trial to assess the impact of the yogurt.
Results showed that the average AD severity scores had dropped from about 40 points to nearly 20 points by the end of the trial.
There was also reduced medicine use due to improvements in AD symptoms.
However, the biomarkers involved in the pathology of AD, such as lgE, TARC, LDH, and EOS, did not change.
As a result, the researchers concluded that while yogurt intake had indeed improved AD, the underlying mechanisms however, remained unknown.
What’s at work?
To uncover the underlying mechanisms, the researchers conducted a mouse experiment using all five probiotic strains present in the yogurt.
To induce AD in mice, the researchers applied the chemical 1-fluoro-2, 4-dinitrobenzene (DNFB), which caused the mice to swell in their ears.
Except for L. lactis 11/19-B1 which only took one hour to bring down the ear swelling, all the other four probiotic strain took six hours before significant improvement was seen.
“These results suggested that the L. lactis 11/19-B1 contributed the most to the suppression of AD symptoms in the human clinical test,” the researchers said.
Even more research
More research was conducted to validate the role of L. lactis 11/19-B1 in suppressing AD.
The researchers went on to compare L. lactis 11/19-B1 with L. bulgaricus using a mice model.
They found that the mice which consumed L. lactis 11/19-B1 group had significantly suppressed inflammatory symptoms on their dorsal skin and ears when compared to the control group.
Such effects, however, were not seen in the mice which consumed L. bulgaricus.
The researchers explained that L. lactis11/19-B1 had worked by suppressing the formation of cells linked to inflammation, including Th1, Th2, and Th17.
“These results indicated that L. lactis 11/19-B1 is a promising candidate as a functional food to alleviate atopic dermatitis,” the researchers concluded.
Effect of the Lactococcus Lactis 11/19-B1 Strain on Atopic Dermatitis in a Clinical Test and Mouse Model
Authors: Suzuki, et al