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Trial registered on ANZCTR


Registration number
ACTRN12625000138482
Ethics application status
Approved
Date submitted
24/01/2025
Date registered
7/02/2025
Date last updated
7/02/2025
Date data sharing statement initially provided
7/02/2025
Type of registration
Prospectively registered

Titles & IDs
Public title
Effects of calcium on gut functions and blood glucose in healthy humans
Scientific title
Effects of intraduodenal calcium on plasma glucose, glucoregulatory hormones and gastric emptying in response to a mixed-nutrient drink in healthy adult males aged 18 to 55 years
Secondary ID [1] 313712 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Postprandial blood glucose 336307 0
Condition category
Condition code
Diet and Nutrition 332841 332841 0 0
Obesity
Oral and Gastrointestinal 332842 332842 0 0
Normal oral and gastrointestinal development and function
Metabolic and Endocrine 332843 332843 0 0
Normal metabolism and endocrine development and function
Musculoskeletal 332844 332844 0 0
Normal musculoskeletal and cartilage development and function

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The intervention in this study consists of a 75-min intraduodenal infusion of an isotonic solution containing either calcium chloride (CaCl2) or control (saline).

Participants enrolled into the study will receive, in randomised, double-blind fashion
(i) Saline (control),
(ii) 500 mg CaCl2,
(iii) 1000 mg CaCl2,

each occurring on separate sessions. Each study session will be 4-6 hours in duration and will be separated by at least 4 (and up to 10) days. Studies will be carried out in the Clinical Research Facility of the Adelaide Medical School, the University of Adelaide, by staff and students trained in the required techniques. To ensure adherence to the intervention, research staff will closely supervise the participants throughout the study visit.

Participants will be required to consume a standardised dinner meal (beef lasagne; total energy content: 602_kcal; McCain Food, Wendouree, Victoria, Australia) the night before each visit by no later than 7 pm. After fasting for ~ 13.5 hours overnight and refraining from exercise and alcohol during the previous 24 hours, participants will arrive at the laboratory at 8.30 am. Upon arrival and after confirming adherence to the study requirements, their vital signs, including blood pressure, heart rate and body temperature, will be measured to establish baseline values for safety, and they will be monitored throughout the study. Then, a 17-channel manometric catheter will be inserted through an anaesthetised nostril and allowed to pass through the stomach and into the duodenum by peristalsis. The infusion port will be positioned ~ 14 cm distal to the pylorus. The correct positioning of the catheter will be monitored continuously by measurement of the transmucosal potential difference in the stomach (~ -40 mV) and the duodenum (~ 0 mV). Once the catheter has been positioned correctly, an intravenous cannula will be placed into a forearm vein for regular blood sampling. At t = -30 min, a baseline blood sample (7 ml), visual analogue scale (VAS) questionnaire to assess GI symptoms and breath sample to assess gastric emptying will be collected. Then infusion of one of the study treatments (i.e, i) saline, ii) 500 mg CaCl2 or iii) 1000 mg CaCl2) will commence and continue for 75 minutes (t = -30 to t = 45). At t = -1 min, participants will consume, within 1 min, a mixed-nutrient drink (Nestle, 500 kcal, 350 ml) labelled with 150 mg of 13C-acetate for measurement of gastric emptying by non-invasive breath sampling at regular intervals, for subsequent analysis of 13CO2. Blood samples for the measurement of plasma hormone concentrations and glucose, and VAS scores, will be collected before and after the mixed-nutrient drink. At t = 240 min, after collecting final blood and breath samples and VAS scores, the i.v. cannula will be removed and participants will be served a light lunch, after which they will be allowed to leave the laboratory. A total of 98 mL of blood (14 sampling time points, 7 mL each) will be taken on each study day (study total of 302 mL).
Intervention code [1] 330311 0
Treatment: Other
Comparator / control treatment
Saline (sodium chloride 0.9%)
Control group
Placebo

Outcomes
Primary outcome [1] 340380 0
Plasma glucose concentrations
Timepoint [1] 340380 0
Plasma will be obtained from venous blood samples collected at baseline (t = -30 min), and then at regular time points before and after the drink (t = -25, -15, 0, 10, 20, 30, 45, 60, 75, 90, 120, 180, 240 min). where t = -30 min is just prior to infusion commencement and t = 240 min is 240 minutes following ingestion of the mixed-nutrient with drink.
Secondary outcome [1] 443911 0
Gastric emptying
Timepoint [1] 443911 0
Breath samples will be collected in sealed tubes at baseline (t = -30) (prior to treatment administration), every 5 minutes for the first hour after the drink (t = 0 to t = 60 min), and then every 10 minutes from t = 60 to t = 240 min.
Secondary outcome [2] 443915 0
Plasma concentrations of glucagon-like peptide-1 (GLP-1)
Timepoint [2] 443915 0
This will be assessed from venous blood samples that will be collected at baseline (t = -30 min), and then at regular time points before and after the drink (t = -25, -15, 0, 10, 20, 30, 45, 60, 75, 90, 120, 180, 240 min).
Secondary outcome [3] 443925 0
Plasma concentrations of glucose-dependent insulinotropic polypeptide (GIP)
Timepoint [3] 443925 0
This will be assessed from venous blood samples that will be collected at baseline (t = -30 min), and then at regular time points before and after the drink (t = -25, -15, 0, 10, 20, 30, 45, 60, 75, 90, 120, 180, 240 min).
Secondary outcome [4] 444460 0
Plasma concentrations of cholecystokinin (CCK)
Timepoint [4] 444460 0
This will be assessed from venous blood samples that will be collected at baseline (t = -30 min), and then at regular time points before and after the drink (t = -25, -15, 0, 10, 20, 30, 45, 60, 75, 90, 120, 180, 240 min).
Secondary outcome [5] 444462 0
Plasma concentrations of C-peptide
Timepoint [5] 444462 0
This will be assessed from venous blood samples that will be collected at baseline (t = -30 min), and then at regular time points before and after the drink (t = -25, -15, 0, 10, 20, 30, 45, 60, 75, 90, 120, 180, 240 min).
Secondary outcome [6] 444463 0
Plasma concentrations of glucagon
Timepoint [6] 444463 0
This will be assessed from venous blood samples that will be collected at baseline (t = -30 min), and then at regular time points before and after the drink (t = -25, -15, 0, 10, 20, 30, 45, 60, 75, 90, 120, 180, 240 min).
Secondary outcome [7] 444464 0
Plasma concentrations of insulin
Timepoint [7] 444464 0
This will be assessed from venous blood samples that will be collected at baseline (t = -30 min), and then at regular time points before and after the drink (t = -25, -15, 0, 10, 20, 30, 45, 60, 75, 90, 120, 180, 240 min).
Secondary outcome [8] 444465 0
GI symptoms (nausea and bloating) will be assessed as a composite secondary outcome.
Timepoint [8] 444465 0
These will be completed at regular time points before and after the drink (t = -30, -15, 0, 10, 20, 30, 45, 60, 75, 90, 105, 120, 135, 150, 180, 210, 240 min).

Eligibility
Key inclusion criteria
Healthy
Normal weight (BMI 19-25 kg/m2)
Minimum age
18 Years
Maximum age
55 Years
Sex
Males
Can healthy volunteers participate?
Yes
Key exclusion criteria
Each participant will be questioned prior to the study to exclude:
• significant GI symptoms, disease or surgery
• use of prescribed or non-prescribed medications (including vitamins and herbal supplements) which may affect energy metabolism, GI function, body weight or appetite (e.g. domperidone, cisapride, anticholinergic drugs (e.g. atropine), metoclopramide, erythromycin, hyoscine, orlistat, green tea extracts, Astragalus, St Johns Wort etc.)
• lactose intolerance/other food allergy(ies)
• current gallbladder or pancreatic disease
• cardiovascular or respiratory diseases
• individuals with low ferritin levels (males <30 ng/mL), or who have donated blood in the 12 weeks prior to taking part in the study
• any other illnesses as assessed by the investigator (including chronic illnesses not explicitly listed above)
• high performance athletes
• current intake of > 2 standard drinks on > 5 days per week
• current smokers of tobacco (cigarettes, cigars, pipes, sheesha, chewing, vaping etc.)
• recreational drug use, e.g marijuana
• current intake of any illicit substance
• vegetarians
• inability to tolerate nasoduodenal tube
• inability to comprehend study protocol
• restrained eaters (score >12 on the 3-factor eating questionnaire)

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Eligible volunteers are assigned a participant number and randomised treatment for each study visit. Randomisation involves contacting the holder (study assistant) of the randomisation table to inform them of participant details and study dates. The unblinded study assistant is, therefore, responsible for allocating a random treatment to the participant and administering the dose.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
The randomisation is generated using a 3x3 Latin Square design, with subjects randomly allocated to one of three treatment sequences. Randomisation using blocks of size 3 will be generated with sealedenvelope.com.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint/s
Statistical methods / analysis

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
24/03/2025
Actual
Date of last participant enrolment
Anticipated
31/12/2025
Actual
Date of last data collection
Anticipated
9/01/2026
Actual
Sample size
Target
15
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
SA

Funding & Sponsors
Funding source category [1] 318237 0
Self funded/Unfunded
Name [1] 318237 0
Christine Feinle-Bisset
Country [1] 318237 0
Australia
Primary sponsor type
Individual
Name
Prof Christine Feinle-Bisset, Adelaide Medical School & CRE in Translating Nutritional Science to Good Health, University of Adelaide
Address
Country
Australia
Secondary sponsor category [1] 320564 0
Individual
Name [1] 320564 0
Prof Michael Horowitz, Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide Medical School & CRE in Translating Nutritional Science to Good Health, University of Adelaide
Address [1] 320564 0
Country [1] 320564 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 316829 0
Central Adelaide Local Health Network HREC
Ethics committee address [1] 316829 0
Level 3, Roma Mitchell Building 136 North Terrace Adelaide SA 5000
Ethics committee country [1] 316829 0
Australia
Date submitted for ethics approval [1] 316829 0
12/12/2024
Approval date [1] 316829 0
16/12/2024
Ethics approval number [1] 316829 0
13243

Summary
Brief summary
Recent studies have demonstrated that calcium, in the doses of 500 mg and 1000 mg, stimulates gut hormones and pyloric pressures and suppresses energy intake. Given the key role of these GI hormones and pyloric pressures in the regulation of gastric emptying, which in turn is a key determinant of the lowering of blood glucose after a meal, we propose to investigate the dose-related effects of intraduodenal calcium infusion on gastric emptying, glucoregulatory hormones, and blood glucose in response to a mixed-nutrient drink in healthy participants.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 139134 0
Prof Christine Feinle-Bisset
Address 139134 0
Adelaide Medical School University of Adelaide Level 5 Adelaide Health and Medical Sciences Building, Cnr George St and North Tce, Adelaide, SA 5005
Country 139134 0
Australia
Phone 139134 0
+61 8 8313 6053
Fax 139134 0
Email 139134 0
[email protected]
Contact person for public queries
Name 139135 0
Prof Christine Feinle-Bisset
Address 139135 0
Adelaide Medical School University of Adelaide Level 5 Adelaide Health and Medical Sciences Building, Cnr George St and North Tce, Adelaide, SA 5005
Country 139135 0
Australia
Phone 139135 0
+61 8 8313 6053
Fax 139135 0
Email 139135 0
[email protected]
Contact person for scientific queries
Name 139136 0
Prof Christine Feinle-Bisset
Address 139136 0
Adelaide Medical School University of Adelaide Level 5 Adelaide Health and Medical Sciences Building, Cnr George St and North Tce, Adelaide, SA 5005
Country 139136 0
Australia
Phone 139136 0
+61 8 8313 6053
Fax 139136 0
Email 139136 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.