Effects of food containing Lactococcus lactis strain T21 on the improvement of skin condition: a randomized, double-blind, placebo-controlled, parallel-group study.

Abstract

This research aimed to examine the effect of daily intake of food containing Lactococcus lactis strain T21 (T21) on skin conditions and inflammation-related markers in healthy adults who experience itching because of dry skin and have an atopic predisposition. A randomized, double-blind, placebo-controlled parallel-group study was conducted on 44 subjects aged 20 to 64 years. Subjects were randomly assigned to receive a T21-containing food or placebo daily for 8 weeks. The hydration of stratum corneum, trans-epidermal water loss, skin brightness (L*), skin redness (a*), and quality of life (QOL) scores were evaluated. Moreover, SCCA2, Th1/Th2, peripheral blood eosinophil count, TGF-β1, TARC, total IgE, and LDH were measured as inflammation-related markers. The results showed that, compared with the placebo, food containing T21 reduced trans-epidermal water loss in the neck and increased neck skin brightness (L*) after 8 weeks of consumption. Furthermore, a stratified analysis in subjects with a history of atopy showed improvements in neck skin redness (a*) and skin-related QOL. No significant improvement in inflammation-related markers was observed. Intake of food containing T21 for 8 weeks in healthy adult with atopic predisposition was suggested to improve skin barrier function in the neck and brightness in the neck skin. Furthermore, the results also suggested that it had the effect of improving rough skin and reducing discomfort due to dryness in healthy adults with a history of atopy.