BUDAPEST, HUNGARY The oral probiotic Lactobacillus paracasei achieved substantial, clinically meaningful reductions in dandruff in a double-blind, placebo-controlled randomized trial.
Consumption of the probiotic also resulted in several secondary benefits, including reduced scalp erythema, itching, and greasiness, along with a steady decline over time in scalp Malassezia yeast counts, Dr. Audrey Gueniche reported at the annual congress of the European Society for Dermatological Research.
She and her coworkers at L'Oréal in Clichy, France, had previously shown that the probiotic speeds recovery of skin barrier function following controlled damage induced by tape stripping. They also demonstrated that L. paracasei helps regulate skin immune function.
Since those defects play an important role in dandruff conditions, the investigators decided to explore L. paracasei as a potential treatment for this common flaky scalp condition.
Thirty white men with moderate to severe dandruff were randomized to 57 days of daily consumption of L. paracasei in powder form or to placebo. Participants had to agree not to consume yogurt or other food products produced by the bacterial fermentation of milk during the trial and not to alter their customary face and scalp hygiene routine.
Biweekly clinical assessments documented declining levels of free and adherent dandruff, the coprimary study endpoints. The divergence between probiotic and placebo became significant after 45 weeks. After 57 days, the probiotic group had a 70% reduction from baseline in their standardized free dandruff score and a 72% decrease in adherent dandruff, compared with reductions of 23% and 34%, respectively, in the placebo group.
Investigator ratings of scalp erythema showed a 58% reduction in the probiotic group after 57 days and a 31% decrease with placebo. The reductions in dandruff and erythema scores were still maintained 1 week after the end of probiotic supplementation, according to Dr. Gueniche.
Global efficacy ratings made by blinded investigators on day 57 showed that 64% of patients in the probiotic arm were scored as having "good improvement" or "total healing," compared with 27% of controls, she reported.
Patients in the probiotic group rated their dandruff as reduced by 57% at the study's end, compared with a self-assessed 16% decrease in the placebo group. The L. paracasei group rated its scalp pruritus as 47% improved, versus a 13% reduction for controls. The probiotic users also rated their scalp erythema as 72% improved, compared with a 43% reduction reported in the placebo group.
Total Malassezia yeast counts showed a significant decrease over time in the probiotic group. In terms of M. restricta and M. globosathe two species that have been identified as the major players in dandruff conditionsscalp counts increased sharply in the placebo group from day 15 on but remained steady over time in the probiotic treatment arm, Dr. Gueniche said.
Source Elsevier Global Medical News