EFFECTS OF INGESTING MILK FERMENTED BY LACTOCOCCUS LACTIS H61 ON SKIN PROPERTIES AND HEALTH BIOMARKERS IN MIDDLE-AGED WOMEN: A RANDOMIZED, DOUBLE-BLIND STUDY

Objective: Previously, we showed that ingestion of fermented milk made by only Lactococcus lactis strain H61 (H61-fermented milk) improves various skin properties in young Japanese women (age, around 20 y). Because the condition of human skin varies with age, we investigated the effects of H61-fermented milk on skin properties of middle-aged women. Design and setting: A randomized, double-blind trial in a clinical research setting. Participants: Healthy, middle-aged, female volunteers (n = 23; age: 36–62 y). Intervention: H61-fermented milk (1010 CFU) or conventional yogurt (1010CFU of both Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus; a reference food) was given daily for 4 weeks. Measurements: Before and at the end of the 4-week treatment, we measured skin hydration (inner forearms and cheek) and sebum content (cheek only). In addition, salivary samples were collected for analysis of immune, stress, and inflammation biomarkers. Self-questionnaires (regarding skin and general health conditions) were done at week 4. Results: By mechanical analysis, the interventions did not alter the skin properties of either group. At week 4, self-questionnaire skin scores for elasticity and texture were significantly higher; scores for darkness tended to be improved in the H61-fermented milk group than the conventional yogurt group. In the general health condition section, diarrhea was significantly more prevalent in the H61-fermented milk than in the conventional yogurt group. The intervention did not alter immunoglobulin A, cortisol, α-amylase, and C-reactive protein levels in saliva. Conclusions: According to self-questionnaires, H61-fermented milk provides beneficial effects on some skin properties of middle-aged women. This intervention would be useful for increasing the quality of life in an aging population after characterizing the beneficial effect by mechanical analysis in future study.