The placebo-controlled, double blind parallel intervention trial "PostWelLB" aims to test whether 3 months of daily supplementation with the postbiotic product "Humiome® Post LB" (HPLB; 340 mg / day) can reduce self-reported stress (PSS10 questionnaire)- in an older (50 - 75 years; all genders) population in France.

The clinical study "PostWelLB" aims to test whether 3 months of daily supplementation with the postbiotic product "Humiome® Post LB" (HPLB) can reduce stress in an older population compared with placebo.

The investigational product (IP) HPLB is a postbiotic according to the International Scientific Association of Probiotics and Prebiotics (ISAPP), who defined postbiotics as "preparations of inanimate micro-organisms or components thereof that provide a health benefit on the host". In essence, HPLB is a fermentation product containing heat inactivated bacterial bodies of Limosilactobacillus fermentum (CNCM I-2998) and Lactobacillus delbrueckii (CNCM I-4831) and metabolite-rich spent fermentation medium (mainly lactic acid). The product also contains lactose, which is used as drying support.

HPLB was developed from an over-the-counter drug, Lactéol, which has been used for decades in more than 30 countries in support of oral rehydration in acute diarrhoea and to improve digestive comfort. Lactéol has an extensive safety record and has been studied in several clinical trials in which it has been shown to reduce digestive upset, improve abdominal comfort, reduce occasional bloating, and help achieve or maintain normal bowel movements.

In addition to effects on digestive health, recent preclinical studies on mice and dogs suggested that HPLB can also affect mood and stress, in line with the emerging concept that the intestinal microbiome may affect wellbeing.

In the present placebo-controlled, double blind clinical trial, the investigators therefore wish to test if daily supplementation with HPLB can reduce stress and improve wellbeing. This will be tested in older volunteers, because the risk of stress increases with age. Verum or placebo will each be administered daily for 12 weeks in capsules made from plant-based material which each also contain small amounts of a widely used flowing agent (magnesium stearate).

Additional endpoints of the trial relate to sleep quality, digestive health, and faecal microbiome composition.

INCLUSION CRITERIA:

• Men and women aged between 50 and 75 years old (limits included),
• Body mass index (BMI) ≥ 18.5 and < 30 kg/m²
• Presenting a level of psychological stress characterized by a PSS-10 score ≥ 14 and ≤ 26,
• For women: not at risk of pregnancy (as per definitions of Appendix 13) Participants currently of childbearing potential, using an effective method of contraception.
• Menopausal without hormone replacement therapy (estrogenic replacement therapy stopped since more than 3 months can be included)
• Good general and mental health according to the opinion of the investigator: No relevant abnormalities from medical history nor from the medical consultation
• Agreeing to maintain lifestyle habits during the study (same dietary and physical activity habits)
• Able and willing to participate to the trial by complying with the protocol procedures as evidenced by a dated and signed ICF
• Affiliated with a social security scheme,
• With access to a health-care provider, who can be contacted by the CRO, and who reside in areas with available emergency health services,
• Agreeing to be registered in the national database of subjects participating in clinical research,
• Having a smartphone or personal computer compatible with the eConsult and ePRO applications.

EXCLUSION CRITERIA:

• Suffering from a metabolic disorder such as treated or untreated diabetes,
• Suffering from thyroid dysfunction, high blood pressure or other metabolic disorders treated for less than 6 months and/or non-stabilized,
• Suffering from a severe chronic disease: cancer, HIV, renal failure, hepatic or biliary disorders ongoing (except for cholecystectomy since more than two years and asymptomatic), chronic inflammatory digestive disease, arthritis or other chronic respiratory trouble (except for mild asthma under treatment),
• Suffering from GI disorders found to be inconsistent with the conduct of the study by the investigator (e.g. celiac disease, Chron's disease, etc.),
• With a known food allergy or intolerance or hypersensitivity to any of the trial products' ingredients,
• Women who are pregnant or lactating or intend on becoming pregnant within the following six months,
• Having a history or presence of a psychiatric or neurologic disease including epilepsy, cerebrovascular disturbance, traumatic brain injury, dementia, Alzheimer's Disease, clinical depression, or other clinically significant psychiatric/neurologic condition that could interfere with the interpretation of the study results in the opinion of the investigator,
• Having recently experienced or currently experiencing a significant stress as per investigator's judgment (e.g. grieving, divorce, moving, etc.),
• Having a condition and/or receiving a treatment that may cause immunosuppression (e.g.: under immunomodulating treatment for HIV infection, allograft, auto-immune disease or cancer, etc.)
• Under treatment or dietary supplement which could significantly affect parameter(s) followed during the trial according to the investigator or stopped less than one month prior to V1,
• Under treatment with one or more of the following treatments stopped less than one month prior to V1:
• psychotropic medications (including antidepressants and tranquilizers), stimulant medications, and/or narcotics having an effect on stress, sleep aid medications, supplements, and/or products, including antihistamines, acid-blocking medication (e.g., proton pump inhibitor, H2 blocker),
• Under treatment with an effect on the microbiome such as antibiotics stopped less than one month prior to V1,
• Having a lifestyle deemed incompatible with the trial according to the Investigator as described below:
• Practicing a high-level of physical activity (defined as more than 10 hours of intense physical activity a week, walking excluded),
• Regularly consuming more than 2 standard drinks of alcohol daily or 14 weekly or not agreeing to keep alcohol consumption habits unchanged throughout the study,
• With a significant change in dietary or physical activity habits in the 3 months prior to randomisation (no hyper or hypocaloric diet, no high-protein diet, no prolonged fasting for more than one week, no planned change in the level of sports activity in the next 3 months),
• With a personal history of anorexia nervosa, bulimia, or significant eating disorders according to the Investigator,
• Taking part in another clinical trial or being in the exclusion period of a previous clinical trial,
• Having received, during the last 12 months, indemnities for clinical trial higher or equal to 6000 Euros,
• Under legal protection (guardianship, wardship) or deprived of rights following an administrative or judicial decision,
• Presenting a psychological or linguistic incapability to sign the ICF, Impossible to contact in case of emergency.