“These results suggest that HK L-137 may be beneficial for menopause-related outcomes in women with high stress levels and that its mechanism of action may be mediated through gut barrier-related host responses associated with microbial translocation,” wrote researchers at House Wellness Foods Corporation in Japan, who funded the study, in the journal Nutrients.
During menopause, alterations in the gut microbiome and increased intestinal permeability have been linked to increased microbial translocation, allowing bacteria to enter the systemic circulation and triggering inflammatory responses.
Lactiplantibacillus plantarum L-137 is a bacterial strain originally isolated from a fermented southwest Asian dish made from fish and rice. The heat-killed form HK L-137, marketed by House Wellness Foods, is a postbiotic reported to improve skin barrier function, suppress inflammation in the liver, and lower cholesterol through its immune-mediating and gut-supporting actions.
The current study noted that the benefits to menopausal symptoms and body mass index may be due to previously reported effects of HK L-137, such as immunomodulation, anti-inflammatory effects, improvements in gut barrier function, and modulation of the microbiota.
Study details
The randomized controlled parallel group trial involved 119 Japanese women aged 45–69 years with self-reported daily stress. They consumed either 10 mg HK L-137 or placebo daily for 12 weeks.
The researchers assessed mood, menopausal symptoms, and sleep quality at the start and end of the study using blood, urine, and saliva tests, medical interviews, and questionnaires.
The findings revealed no significant difference between groups in the questionnaire scores for mood state, menopausal symptoms, or sleep quality.
However, serum soluble CD14 (sCD14), a gut barrier function marker, and lactate dehydrogenase (LDH), an inflammatory marker, decreased significantly in the supplement group compared to placebo.
The researchers observed that in participants with higher baseline levels of negative mood, “HK L-137 significantly improved hot flashes item and sleep maintenance score, and was associated with favorable changes in sCD14, LDH, and body mass index versus placebo”.
sCD14 is regarded as a marker of microbial translocation, and the researchers suggested that the significant decreases in the supplement group, compared with increases in the placebo group, indicate that HK L-137 influenced host responses, potentially by strengthening tight junctions and enhancing the mucosal barrier in the gut.
They also noted that a study in obese animals suggested that administration of HK L-137 suppresses weight gain by improving intestinal barrier function.
The supplement may also indirectly influence estrogen-related pathways through effects on the gut environment, as evidenced by the higher estradiol levels in the HK L-137 group.
Noting that the subgroup findings should be interpreted with caution due to inconsistencies across analytical approaches, the researchers recommended future studies with more detailed assessments and research methods.
Source: Nutrients 2026, 18(21), 3641; https://doi.org/10.3390/nu18213641, “Effects of Heat-Killed Lactiplantibacillus plantarum L-137 on Menopause-Related Outcomes and Gut Barrier-Related Biomarkers in Japanese Women: A Randomized, Double-Blind, Placebo-Controlled Trial.” Authors: T. Nakajima et al.
