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FruGut study

Diet is a crucial target for the improvement of human health. In the modern world, diets are diverse, and diet-related diseases are becoming more and more common. In particular, it is becoming increasingly apparent that stool weight, as well as the bacteria that live in our gut, are strongly linked to both diet and health. What we eat has a great impact on the composition of the bacteria of our gut. In turn, the gut bacteria play diverse roles in human health, influencing not only our gut but also our heart health, and even our brain health. Therefore, optimising our gut bacterial composition is vital to our health and wellbeing.

This research study aims to investigate the effects of fruit products on the gut symptoms, gut function and gut bacteria in people with constipation.


Who are we recruiting?

We are looking for healthy people between 18-65 years old with functional constipation and a body mass index between 18.5-29.9 kg/m2. Eligible participants will meet the criteria for constipation and have a habitual low fibre intake. People with gut-related disorders (e.g., coeliac disease, Inflammatory Bowel Disease, diverticular disease) or other chronic disorders (e.g. renal, cardiac or pulmonary) will be excluded. Also, people who have taken certain medications recently known to affect gut motility (e.g. mebeverine, opiates), those who frequently use laxatives, have ongoing alcohol, drug or medication abuse, those who frequently consume fruit products or dislike/have an intolerance or allergy to fruit products, and those who have had recent or extensive gut surgery will not be eligible. Pregnant and breastfeeding women will also be excluded.

What is required of me if I take part?

The study aims to investigate the effect of fruit products on the gut bacteria, as well as gut symptoms and transit time in healthy people with constipation. You will be required to consume fruit products on a daily basis for a total of 4 weeks. You will not be required to make any other changes to your usual diet. The study includes three visits to King’s College London at the Waterloo Campus. You will also be required to provide stool, urine and blood samples and be asked if you would like to take a SmartPill.

A SmartPill is a pill (the size of a large vitamin tablet) that is not digested, passes straight through your digestive system and is expelled during a bowel movement (typically 1-5 days). During this time, you will also be asked to wear a monitor that can be clipped onto clothing. The SmartPill transmits a signal to the monitor every 20 seconds which allows recording of different measurements including pressure, pH and temperature.

All study fruit products will be provided and you will be reimbursed with £100 upon completion.

Project status: Ongoing

Principal Investigator


Contact us

Metabolic Research Unit
Franklin-Wilkins Building
150 Stamford Street