Improving Constipation by Stimulating Fiber Intake Using Personalized Dietary Advice

Rationale: constipation-related complaints are prevalent in 5-20% of the population. Dietary fibers play a crucial role in improving and maintaining gut health, increasing stool weight, stool frequency and improvement of stool consistency. Currently, very few adults meet the recommendation of 30 (females) or 40 (males) grams of fiber per day. Personalized dietary advice may be the solution to increase dietary fiber intake and reduce constipation-related complaints in large populations. Objective: To investigate the effectiveness of personalized dietary advice (PDA) in reducing constipation-related complaints, by increasing dietary fiber intake in people with constipation-related complaints. Study design: This study has a one-group pre-test post-test design with a run-in period. The duration of the study is 8 weeks, which includes a 4-week run-in phase and a 4-week intervention period. All subjects receive the PDA. Study population: adult subjects with constipation-related complaints, defined as predominant Bristol stool form between 1-4 and not satisfied with their bowel habits (scale ranging from 1-10, cut-off \<6). Possibly stool frequency ≤4 stools per week will be included as a definition. Subjects need to have a relatively low dietary fiber intake defined as \<26 grams (females) or \<33 grams (males), which is ≥15% below the recommendation of fiber intake. Intervention: personalized advice based on their habitual food pattern (as assessed using a food frequency questionnaire) and preferences. Based on a special algorithm, the PDA provides high fiber alternatives for low-fiber products that subjects currently use, close to their current eating behavior, to help increase dietary fiber intake. This PDA will be provided using an online web-portal. Main study parameters/endpoints:primary outcomes are stool pattern, gastrointestinal complaints and constipation quality of life and severity. Secondary parameters include dietary fiber intake, physical activity, body