Plain English Summary
Background and study aims
There is a convincing body of research showing how different fats elicit different effects on appetite, hunger and fullness, and as a result; energy intake. There are different types of fats called triglycerides that are used for energy. It has been shown that medium-chain triglycerides (triglycerides with a fatty acid chain length of 6-12 carbons, MCT) lead to reduced feelings of hunger and a suppression of food intake compared to long-chain triglycerides (triglycerides with a fatty acid chain length of over 12 carbons, LCT). Likewise, there have been studies suggesting that conjugated linoleic acid (CLA) (a healthy fatty acid that is found in meat and dairy products mostly) may also lead to greater satiation (feeling full) than the LCT found commonly in food. To date, only one study has been conducted to explain which fat has the most potential to be used to promote satiation and therefore decrease energy intake. Furthermore, most of the research currently conducted has been done so in lean individuals. As appetite regulation differs between lean and obese individuals the study of obese individuals can help provide insight into the satiating properties of various lipids, and their potential to be used in weight management strategies. The aim of this study is to compare the effects of two lipids (CLA and MCT) to each other and to a control on fullness in obese and lean controls and examine satiety hormones that influence food intake following the consumption of lipids in obese and lean controls.
Who can participate?
This study will recruit two groups: healthy-weight participants (BMI 18.5-24.9 kg/m2) and 16 obese (BMI 30-40 kg/m2) aged 18-60 who are not restricted eaters.
What does the study involve?
The study involves three non-consecutive test days in a randomised order. After a 24 hour standardisation period and overnight fast, participants come to the laboratory and consume a smoothie breakfast to which MCT, CLA or a control lipid is added (one per test day). Over the next three hours, subjective sensations of appetite, gastric emptying breath tests, and blood samples (via cannulation) are taken in order to elucidate the effects of these lipids on appetite, as well as the mechanisms behind any observed effects. After the data collection period, participants consume an ad libitum lunch to examine the satiety effect of the lipids, and participants are required to fill diet diaries for the remainder of the day and the following 24 hours. Participants are assessed for their fat-related appetite control and their energy intake.
What are the possible benefits and risks of participating?
There are no direct benefits or risks with participating.
Where is the study run from?
Oxford Brookes Centre for Nutrition and Health (UK)
When is the study starting and how long is it expected to run for?
May 2016 to March 2018
Who is funding the study?
1. Oxford Brookes University (UK)
2. TANITA Healthy Weight Community Trust (UK)
Who is the main contact?
Dr Miriam Clegg
Trial website
Contact information
Type
Scientific
Primary contact
Dr Miriam Clegg
ORCID ID
http://orcid.org/0000-0002-8871-0116
Contact details
Oxford Brookes Centre for Nutrition and Health
Oxford
OX3 0BP
United Kingdom
Additional identifiers
EudraCT number
ClinicalTrials.gov number
Protocol/serial number
171082
Study information
Scientific title
A comparison of the satiating properties of medium-chain triglycerides (MCT) and conjugated linoleic acid (CLA) in lean and obese participants
Acronym
Study hypothesis
The study’s two core aims are to:
1. Compare the effects of two functional lipids (CLA and MCT) to each other and to a control for perceived satiety and actual food intake in obese individuals and lean controls.
2. Examine satiety hormones that might be influencing food intake following the consumption of the functional lipids in obese individuals and lean controls.
Ethics approval
Oxford Brooked University, 15/03/2017, ref: UREC 171082
Study design
Randomised cross-over design
Primary study design
Interventional
Secondary study design
Randomised controlled trial
Trial setting
Other
Trial type
Other
Patient information sheet
Not available in web format, please use the contact details below to request a patient information sheet
Condition
Lean and obese individuals
Intervention
Following provision of informed consent and study screening, eligible participants are given weighing scales and a standardisation booklet in order to fulfil standardisation requirements. This requires abstaining from alcohol and strenuous physical activity, and to record all food and drink consumed throughout the 24 hours preceding each trial. This was to be repeated in the same period before the remaining trials.
Participants completed three trials in a random order: control, and the two functional lipids: MCT and CLA.
Upon arriving at the laboratory, participants are to be fitted with a cannula, give a baseline gastric emptying sample (GE), and fill baseline visual analogue scales (VAS) pertaining to appetite. After this, the smoothie breakfast containing the lipid is served, which participants have five minutes to consume. Participants remain in the lab for three hours whilst repeat samples are taken until an ad libitum lunch is served. The ad libitum lunch is a single item buffet (pasta) which is served hot in multiple bowls. Bowls will be replaced once the participant has consumed ½ to ¾ of a bowl.
After the ad libitum lunch finishes, participants are free to leave the laboratory, with another diet diary, which is to be filled for the remainder of the day and following 24 hours.
Gastric emptying breath tests are taken every 15 minutes, visual analogue scales and blood samples every 30 minutes throughout the three hour period.
Intervention type
Other
Phase
Drug names
Primary outcome measure
1. Energy intake assessed by the ad libitum buffet lunch that participants consume at the end of each trial in isolated booths at 180-195 mins (until participants reach satiety)
2. Visual Analogue Scales will be used to measure subjective sensations of appetite: Hunger, Fullness, Desire to Eat, Prospective Food Consumption and Nausea at 0 mins, 30 mins, 60 mins, 90 mins 120 mins and 180 mins
3. Gastric emptying, measured through the 13C octanoic acid breath test at 0 mins, 15 mins, 30 mins, 45 mins, 60 mins, 75 mins, 90 mins, 105 mins, 120 mins, 135 mins, 150 mins, 165 mins and 180 mins
4. Blood parameters implicated in fat-related appetite control: cholecystokinin, acylated ghrelin, PYY and β-hydroxybutyrate. Blood samples taken at 0 mins, 30 mins, 60 mins, 90 mins 120 mins and 180 mins
Secondary outcome measures
1. 48 hour energy intake, through recorded diet diaries completed after the morning in the laboratory and the following day
2. Hedonic properties of the lipid (to outline palatability issues with the breakfasts which may confound the results) assessed by Qualitative Descriptive Analysis at 5 min
Overall trial start date
01/05/2016
Overall trial end date
30/03/2018
Reason abandoned (if study stopped)
Eligibility
Participant inclusion criteria
1. Aged 18-60 years
2. BMI of 18.5-25.0 kg/m2 or 30.0-40.0 kg/m2
Participant type
Healthy volunteer
Age group
Adult
Gender
Both
Target number of participants
Planned Sample Size: 32 total; 16 healthy weight and 16 obese
Total final enrolment
29
Participant exclusion criteria
1. Allergic/intolerant to any of the foods provided in the study
2. Taking medication which could affect appetite
3. Smokers
4. A ‘restrained eater’, as defined by the TFEQ and DEBQ
5. Currently dieting to lose weight
6. Anaemic
7. Vegan
Recruitment start date
12/07/2017
Recruitment end date
01/03/2018
Locations
Countries of recruitment
United Kingdom
Trial participating centre
Oxford Brookes Centre for Nutrition and Health
Oxford Brookes University
Gipsy Lane
Headington
United Kingdom
Oxford
OX3 0BP
United Kingdom
Funders
Funder type
University/education
Funder name
Oxford Brookes University
Alternative name(s)
Funding Body Type
private sector organisation
Funding Body Subtype
Universities (academic only)
Location
United Kingdom
Funder name
TANITA Healthy Weight Community Trust
Alternative name(s)
Funding Body Type
Funding Body Subtype
Location
Results and Publications
Publication and dissemination plan
At the close of the trial, participants who have expressed interest in knowing the results of the study will be contacted. The results will be analysed, and written up for publication to relevant scientific journals. Results will also be presented at relevant conferences.
IPD sharing statement:
The datasets generated during and/or analysed during the current study are/will be available upon request from Dr Miriam Clegg, Oxford Brookes Centre for Nutrition and Health, Department of Sport Health Sciences and Social Work, Faculty of Health and Life Sciences, at mclegg@brookes.ac.uk (+44 1865 484365.
Intention to publish date
01/08/2018
Participant level data
Available on request
Basic results (scientific)
Publication list
2020 results in https://pubmed.ncbi.nlm.nih.gov/32248292/ (added 03/06/2020)