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