The goal of this randomized blinded placebo-controlled clinical trial is to investigate the effect of low- and high-dose supplementation of Acacia fiber on gut health and microbiota composition in adults with occasional constipation in a controlled diet context. Acacia fiber is a soluble dietary fiber with prebiotic properties, and this study evaluates its role in modulating gut microbiota and associated gastrointestinal outcomes. Acacia fiber has previously demonstrated improvements in stool frequency in the context of an irritable bowel syndrome with constipation (IBS-C)-characterized population. The main questions this study aims to answer are: Does Acacia fiber supplementation (5 g or 10 g) improve the frequency of bowel movements or stool consistency (assessed by Bristol Stool Scale) in the context of healthy population with occasional constipation? Does Acacia fiber benefit on gut health correlates with specific gut microbiota modulation characterised by shotgun sequencing? What are mechanistical faecal & blood markers that may support this correlation? Researchers will compare low-dose Acacia fiber (5 g), high-dose Acacia fiber (10 g), and placebo to see if Acacia fiber modulates gut microbiota composition in a manner consistent with prebiotic activity and whether these changes are associated with improvements in bowel movement frequency and stool consistency. Participants will:

• Take a daily supplement of either 5 g Acacia fiber, 10 g Acacia fiber, or placebo
• Complete study diaries, including the Bowel Habits Diary and Bristol Stool Scale
• Complete the Patient Assessment of Constipation Quality of Life, modified Gastrointestinal Symptoms Rating Scale, and sleep and stress Likert scales
• Complete 3-day food records

Inclusion Criteria:

• Males and females aged between 30 and 60 years old, inclusive

• Body Mass Index (BMI) between 18.5 to 29.9 kg/m², inclusive

• Stable body weight defined as a <5% change in body weight in the three months prior to baseline as assessed by the Qualified Investigator (QI)

• Participants must meet the following criteria of occasional constipation for the past 3 months. This will be assessed at screening and confirmed over a 2-week period prior to baseline:

  • 5 CSBMs per week AND either one of the following: at least 25% of Bowel Movements (BMs) are BSS type 1 or 2 OR straining for most of the BMs (≥50%), defined as 3 minutes or more during BM, as assessed by the QI

OR,

At least 50% of BMs are BSS type 1 and 2, as assessed by the QI

OR,

≤ 3 CSBMs per week as assessed by the QI

• Low to moderate fiber intake, defined as < 18 g per day for women and < 22 g per day for men, as assessed by the Food Frequency Questionnaire (FFQ)
• Females not of child-bearing potential, defined as those who have undergone a sterilization procedure (e.g. hysterectomy, bilateral oophorectomy, bilateral tubal ligation, complete endometrial ablation) or have been post-menopausal for at least 1 year prior to screening

OR,

Individuals of child-bearing potential must have a negative baseline urine pregnancy test and agree to use a medically approved method of birth control for the duration of the study. All hormonal birth control must have been in use for a minimum of three months. Acceptable methods of birth control include:

Hormonal contraceptives including oral contraceptives, hormone birth control patch (Ortho Evra), vaginal contraceptive ring (NuvaRing), injectable contraceptives (Depo-Provera, Lunelle), or hormone implant (Norplant System)

Double-barrier method

Intrauterine devices

Non-heterosexual lifestyle and agrees to use contraception if planning on changing to heterosexual partner(s)

Vasectomy of partner at least 6 months prior to screening

Abstinence and agrees to use contraception if planning on becoming sexually active during the study

• Agrees to maintain current lifestyle habits (diet, sleep, physical activity, medications, supplements, and without any new addition) as much as possible throughout the study
• Provided voluntary, written, informed consent to participate in the study
• Healthy as determined by medical history and laboratory results as assessed by the Qualified Investigator (QI)
• Willing and able to comply with the study protocol (e.g., concomitant treatment) and complete questionnaires, records and diaries associated with the study, as well as complete all clinic visits

Exclusion Criteria:

• Individuals who are pregnant, breast feeding, or planning to become pregnant during the study
• Allergy, sensitivity or intolerance, to study products
• Chronic constipation, as assessed by the QI
• Following a specific diet (e.g., vegetarian, paleo, ketogenic, carnivore)
• Colonoscopy within four weeks prior to baseline or during the study
• Gastrointestinal related sensitivities including gluten and lactose intolerance
• Current or history of any significant diseases of the gastrointestinal tract (e.g., irritable bowel syndrome, irritable bowel disease, gastrointestinal surgery) as assessed by the QI
• Unstable metabolic disease, autoimmune disease or chronic diseases as assessed by the QI
• Unstable hypertension. Treatment on a stable dose of medication for at least 3 months will be considered by the QI (See Section 8.3.1)
• Type I diabetes
• Type II diabetes if on insulin treatment. Type II diabetics on stable medication for at least three months and an Hemoglobin A1c (HbA1c) of <8.0% may be included after assessment by the QI on a case-by-case basis
• Significant cardiovascular event in the past 6 months. Participants with no significant cardiovascular event on stable medication may be included after assessment by the QI on a case-by-case basis
• History of or current diagnosis with kidney and/or liver diseases as assessed by the QI on a case-by-case basis, with the exception of history of kidney stones in participants who are symptom free for 6 months
• Self-reported confirmation of current or pre-existing thyroid condition. Treatment on a stable dose of medication for at least 3 months will be considered by the QI
• Major surgery in the past 3 months or individuals who have planned surgery during the course of the study. Participants with minor surgery will be considered on a case-by-case basis by the QI
• Cancer, except skin basal cell carcinoma completely excised with no chemotherapy or radiation with a follow up that is negative. Volunteers with cancer in full remission for more than five years after diagnosis are acceptable
• Individuals with an autoimmune disease or are immune compromised as assessed by the QI
• Self-reported confirmation of a Human Immunodeficiency Virus (HIV)-, Hepatitis B- and/or C-positive diagnosis as assessed by the QI
• Self-reported confirmation of blood/bleeding disorders as assessed by the QI
• Use of prescribed cannabinoid products
• Chronic use of cannabinoid products (>2 times/week). Occasional users will be required to washout for at least 60 days and abstain for the duration of the study period
• Regular use of tobacco or nicotine products within the past three years, as assessed by the QI.
• Alcohol intake average of >2 per day or >10 per week of standard drinks as assessed by the QI
• Alcohol or drug abuse within the last 12 months
• Current use of prescribed and/or over-the-counter (OTC) medications, supplements, and/or consumption of food/drinks that may impact the efficacy and/or safety of the investigational product, gut transit and/or constipation, or gut microbiota characteristics (e.g., fibre, pre- pro- postbiotic, polyphenols extract, etc.) (Section 8.3)
• Clinically significant abnormal laboratory results at screening as assessed by the QI
• Blood donation 30 days prior to baseline, during the study, or a planned donation within 30 days of the last study visit
• Participation in other clinical research studies 60 days prior to baseline, as assessed by the QI
• Individuals who are unable to give informed consent
• Any other condition or lifestyle factor, that, in the opinion of the QI, may adversely affect the participant's ability to complete the study or its measures or pose significant risk to the participant

Sponsor representatives will be masked to randomization assignments and treatment groups during the conduct of the study.