According to a study funded by Asahi and conducted by researchers from Tokushima University Graduate School and Asahi Quality & Innovations, the CP2305 group reported fewer premenstrual symptoms than the placebo group, particularly psychological symptoms.
Originally isolated from the stool of a healthy volunteer, previous studies have shown that a daily intake of CP2305 can relieve fatigue and stress-related symptoms in long-distance male runners, as well as reduce stress among students, and improve clinical symptoms of patients with irritable bowel syndrome.
However, no studies have been conducted on CP2305’s effects on premenstrual symptoms.
“To the best of our knowledge, this is the first study to evaluate the effects of probiotics or paraprobiotics on premenstrual symptoms,” researchers wrote in the Journal of Functional Foods.
More than 90% of young women suffer from premenstrual symptoms including physical or emotional discomfort.
The current findings suggest that CP2305 may improve emotional symptoms in healthy young women.
Study design
The double-blind, placebo-controlled, parallel-group clinical trial enrolled 25 females in the CP2305 group and 31 in the placebo group.
They were between 20 to 35 years old, with a regular menstrual cycle, and recruited from Tokushima University, Japan.
Participants were instructed to ingest two tablets (placebo or CP2305) once daily over the course of six menstrual cycles (approximately 183 days).
During the trial, participants were asked to refrain from fermented milks, foods containing live lactic acid bacteria, or other probiotic or prebiotic products.
The CP2305-containing tablet contained heat-inactivated CP2305 (1 × 1010 bacterial cells per 2 tablets), maltose, dextrin, starch, and vegetable oil.
The placebo tablet was similar except without CP2305.
Questionnaires were administered to assess the physical and mental health of participants. These assessed degree of anxiety, depression, tiredness, and sleep quality.
Premenstrual symptoms for every menstrual cycle were also recorded in a questionnaire.
In this study, researchers wanted to measure the concentration of salivary reproductive hormones such as hormones estradiol (E2) and progesterone (P4), cortisol, and chromogranin A (CgA).
Premenstrual symptoms are typically associated to periodic changes in the levels of the reproductive hormones such as E2 and P4. E2 and P4 are said to influence emotions, sleep patterns, and E2 is said to regulate various neurotransmitter systems, including serotonin and dopamine, which affect mood.
Saliva samples were collected during the luteal phase (3 to 6 days prior to menstruation) and the follicular phase (3 to 6 days after menstruation).
The primary outcome was a change in participants’ psychological conditions during premenstrual period, and the secondary outcomes were changes in participants’ physical conditions during the same period.
Improve mental symptoms but not physical
The CP2305 group saw psychological and sleep-related premenstrual symptoms improved, with significantly lower scores for “depressed mood,” “anxious,” “decreased interest in activities,” “easy fatigability,” and “sleep more” compared to the placebo group.
However, CP2305 intake was not associated to improving all physical symptoms measured.
Symptoms such as breast tenderness and swelling, were reduced in the placebo group, but remained unchanged in the CP2305 group. These symptoms tend to be associated to water retention.
Researchers said: “These data suggest that daily intake of CP2305 may increase fluid retention during the luteal phase.”
Although scores for other physical symptoms such as “constipation”, “having acne,” and “vaginal discharge” were significantly lower in the CP2305 group compared with the placebo group.
Salivary hormones
In the follicular phase, daily intake of CP2305 did not influence salivary E2, nor P4 post-menstruation levels.
In the luteal phase (pre-menstrual), P4 levels were higher while E2 levels were maintained in the CP2305 group.
Salivary cortisol and CgA levels were not affected by CP2305 administration.
“These data suggest that daily intake of CP2305 may affect E2 and P4 secretion during the luteal phase, thereby ameliorating premenstrual symptoms,” researchers wrote.
“Therefore, daily intake of CP2305 tablets might improve the premenstrual psychological symptoms of healthy young women in association with changes in reproductive hormone levels.”
Future steps
Researchers said CP2305 appeared to affect the central nervous system, resulting in attenuation of the stress-induced response and improvement of sleep quality.
In addition, they think CP2305 may increase the diversity of the gut microbiota, particularly increasing bacteria that produce short chain fatty acids (SCFAs).
According to them, gut metabolites produced by microbiota, such as SCFAs, may influence the regulation of E2 and P4 metabolites, resulting in fluctuation of premenstrual symptoms.
In this study, changes in the gut microbiome by CP2305 intake were not assessed, so researchers recommended: “Further investigations are warranted to elucidate whether alteration of the microbiota by CP2305 is associated with changes in the levels of reproductive hormones.
“Our findings in this study provide new evidence for the unexplored ability of CP2305 to ameliorate psychological premenstrual symptoms,” researchers wrote.
Further mechanistic studies will reveal better the impact of the daily intake of paraprobiotic CP2305 on young women’s mental health.
Source: Journal of Functional Foods
https://doi.org/10.1016/j.jff.2021.104426
“Daily intake of Lactobacillus gasseri CP2305 ameliorates psychological premenstrual symptoms in young women: A randomized, double-blinded, placebo-controlled study”
Authors: Kensei Nishida, et al.
