Clinical trial NCT05892003: Scot Sweet Study (Interaction of a Non-nutritive Sweetener With a High-fibre Weight Loss Diet)
Official title: Healthy Diets for a Healthy Weight: Exploring Physiological Mechanisms Related to Dietary Fibre and Non-Nutritive Sweeteners
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Appetitive Behavior
Keywords: fibre
non-nutritive sweetener
weight loss
gut microbiome
glycaemic control
Lead sponsor: University of Aberdeen
Sponsor class: OTHER
First posted: 2023-06-07
Enrollment: 20
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: BASIC_SCIENCE

Brief summary: The investigators present a weight loss diet intervention study, to be conducted as a within-subject design, with all food and beverages provided, to assess interaction of non-nutritive sweetener (sucralose) with a high-fibre weight loss diet, on markers of gut health in humans. This study will allow assessment of the effects of a non-nutritive sweetener (sucralose) with a high-fibre (soluble fibre, fructo-oligosaccharides, FOS) diet on metabolic health and activity and composition of gut microbiota, by a controlled human diet intervention study. The investigators propose to recruit participants living with obesity, with a poor diet quality (moderate habitual fibre intake) to additionally address diet inequalities in the research approach, and this will also allow examine the time-course of adaptation of the gut microbiome (measured in faecal samples). The investigators will also assess changes in free-living glycaemic control with addition of dietary fibre and bio-markers of health.


Eligibility criteria: Inclusion Criteria:

* healthy but overweight/obese (BMI 28-40kg/m2) males and females (postmenopausal, using the oral contraceptive pill or some form of hormonal contraceptive)
* moderate habitual fibre intake (18-23g/day)

Exclusion Criteria:

Medication exclusion criteria:

* antibiotic use (within the past 3 months due to impact on gut microbiota)
* anti-depressants (current)
* smoking or vaping
* weight loss medication

Medical exclusion criteria:

* Females who are planning to be pregnant, are pregnant or are breastfeeding
* Anyone with food allergies, self-reported food sensitivity or intolerance
* Anyone with coeliac disease or gluten intolerance
* Anyone taking medication which may affect their appetite
* Anyone with an eating disorder
* Anyone with diabetes
* Anyone with a gastrointestinal disorder, kidney disease, liver disease or gout
* Anyone suffering from a psychiatric disorder or any type of substance abuse
* Anyone suffering from unregulated thyroid disease

Other exclusion criteria:

* Anyone following a vegetarian or vegan diet
* Anyone following a current weight loss programme (that may be affecting lifestyle, physical activity \& diet) or undergone gastric band/reduction surgery
* Anyone with unsuitable veins for blood sampling
* Anyone who is unable to fluently speak, read and understand English
* Anyone who is unable to comply to an alcohol-free diet for 6 weeks

Current sweetener consumption will not be an exclusion criteria as the Phase 1 - CTRL and Phase 2 - HF WL diets will provide enough of a washout (4 weeks) before the Phase 3 diets containing sucralose are consumed. Participants who do habitually consume sweeteners will be asked not to use them during the study.

Primary outcomes:
measure: Change in gut metabolites (from faecal samples) in response to dietary fibre and non-nutritive sweetener
timeFrame: At baseline and end of each arm (study days 1, 15, 29 and 43)
measure: Change in gut microbiome composition (from faecal samples) in response to dietary fibre and non-nutritive sweetener
timeFrame: At baseline and end of each arm (study days 1, 15, 29 and 43)
measure: Change in gut metabolite production (from faecal samples) in response to dietary fibre and non-nutritive sweetener
timeFrame: At baseline and end of each arm (study days 1, 15, 29 and 43)
Secondary outcomes:
measure: Change in free-living glycaemic control in response to dietary fibre and non-nutritive sweetener
timeFrame: every day of study diets (42days)
measure: Change in glycaemic control in response to dietary fibre and non-nutritive sweetener
timeFrame: At baseline and end of each arm (study days 1, 15, 29 and 43)
Other outcomes:
measure: Change in concentration of blood metabolites in response to dietary fibre and non-nutritive sweetener
timeFrame: At baseline and end of each arm (study days 1, 15, 29 and 43)
measure: Change in concentration of gut hormones in response to dietary fibre and non-nutritive sweetener
timeFrame: At baseline and end of each arm (study days 1, 15, 29 and 43)
measure: Change in lipid profile in response to dietary fibre and non-nutritive sweetener
timeFrame: At baseline and end of each arm (study days 1, 15, 29 and 43)
measure: Change in lipid ratios in response to dietary fibre and non-nutritive sweetener
timeFrame: At baseline and end of each arm (study days 1, 15, 29 and 43)
measure: Change in concentration of urinary metabolites in response to dietary fibre and non-nutritive sweetener
timeFrame: At baseline and end of each arm (study days 1, 15, 29 and 43)
measure: Height
timeFrame: At screening visit only
measure: Change in body weight in response to dietary fibre and non-nutritive sweetener
timeFrame: At screening and 3 times a week on each arm (20 occasions from date of screening up to study day 43)
measure: Change in Body Mass Index (BMI) in response to dietary fibre and non-nutritive sweetener
timeFrame: At screening and 3 times a week on each arm (20 occasions from date of screening up to study day 43)
measure: Change in daily nausea symptoms in response to dietary fibre and non-nutritive sweetener
timeFrame: every day of study diets (42days)
measure: Change in daily bloating symptoms in response to dietary fibre and non-nutritive sweetener
timeFrame: every day of study diets (42days)
measure: Change in daily flatulence symptoms in response to dietary fibre and non-nutritive sweetener
timeFrame: every day of study diets (42days)
measure: Change in daily abdominal cramp symptoms in response to dietary fibre and non-nutritive sweetener
timeFrame: every day of study diets (42days)
measure: Change in daily intestinal rumble symptoms in response to dietary fibre and non-nutritive sweetener
timeFrame: every day of study diets (42days)
measure: Change in daily diarrhoea symptoms in response to dietary fibre and non-nutritive sweetener
timeFrame: every day of study diets (42days)
measure: Change in daily constipation symptoms in response to dietary fibre and non-nutritive sweetener
timeFrame: every day of study diets (42days)
measure: Change in daily bowel movements in response to dietary fibre and non-nutritive sweetener
timeFrame: every day of study diets (42days)
measure: Change in daily hunger rating in response to dietary fibre and non-nutritive sweetener
timeFrame: every day of study diets (42days)
measure: Change in daily fullness rating in response to dietary fibre and non-nutritive sweetener
timeFrame: every day of study diets (42days)
measure: Change in daily desire to eat rating in response to dietary fibre and non-nutritive sweetener
timeFrame: every day of study diets (42days)
measure: Change in retrospective food consumption rating in response to dietary fibre and non-nutritive sweetener
timeFrame: every day of study diets (42days)
measure: Change in appetite in response to dietary fibre and non-nutritive sweetener
timeFrame: every day of study diets (42days)
measure: Change in food intake
timeFrame: at screening (7days) and every day of study diets (42days)
Locations:
city: Aberdeen
country: United Kingdom
facility: Rowett Institute, University of Aberdeen
Study officials:
affiliation: Rowett Institute, University of Aberdeen
name: Alexandra Johnstone, Prof
role: PRINCIPAL_INVESTIGATOR
affiliation: Rowett Institute, University of Aberdeen
name: Alexander Ross, Dr
role: PRINCIPAL_INVESTIGATOR
References: