Effects of Calcium on Gut Functions and Blood Glucose in Humans With Type 2 Diabetes

NCT06942195 | Recruiting

• 1 other identifier: 13243-1
• Study Type: interventional
• Target: 8
• Locations: 1 country
• Sites: 1

Brief Summary

The intervention in this study consists of a 75-min intraduodenal infusion of an isotonic solution containing either of 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, or (iii) 1000 mg CaCl2 in three separate sessions, each of which will be separated by at least 4 (and up to 10) days. Each study session will be 4-6 hours. 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.

Conditions

T2DM

Keywords

Intraduodenal; Calcium; Gastric emptying; Glucoregulatory hormones; Plasma glucose; Human

Outcome Measures

Primary Outcomes (1)

• Plasma glucose concentrations

  Plasma glucose concentrations (mmol/L) will be assessed using glucose oxidase method.

  Blood samples will be collected over 4.5 hours: at baseline (time = -30 minutes), then at regular intervals before and after drink administration (times = -25, -15, 0, 10, 20, 30, 45, 60, 75, 90, 120, 180, 240 minutes).

Secondary Outcomes (3)

• Gastric emptying

  Breath samples will be collected in sealed tubes over 4.5 hours: at baseline (time = -30 minutes) (prior to treatment administration), every 5 minutes after the drink (times = 0 to 60 minutes), then every 10 minutes until 240 minutes post-drink.

• Plasma concentrations of glucoregulatory hormones e.g. glucagon-like peptide (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), C-peptide, glucagon, insulin and cholecystokinin (CCK)

  Blood samples will be collected over 4.5 hours: at baseline (time = -30 minutes), then at regular intervals before and after the drink (times = -25, -15, 0, 10, 20, 30, 45, 60, 75, 90, 120, 180, 240 minutes).

• GI symptoms (nausea and bloating) will be assessed as a composite secondary outcome.

  Visual Analogue questionnaires will be collected over 4.5 hours: at baseline (time = -30 minutes), at regular intervals before and after the drink (times = -25, -15, 0, 20, 30, 45 minutes), then every 10 minutes until 240 minutes.

Study Arms (3)

Ca-1000

ACTIVE COMPARATOR

In this arm, participants will receive a 75-minute intraduodenal infusion of an isotonic solution containing 3.68 g of calcium chloride dihydrate (CaCl₂·2H₂O), dissolved in 225 mL of distilled water.

Other: Ca-1000

Ca-500

ACTIVE COMPARATOR

In this arm, participants will receive a 75-minute intraduodenal infusion of an isotonic solution containing 1.84 g of calcium chloride dihydrate (CaCl₂·2H₂O), dissolved in 225 mL of distilled water. Additionally, 1.2 g of sodium chloride (NaCl) will be added to ensure the solution is isosmotic (300 mOsm).

Other: Ca-500

Control

PLACEBO COMPARATOR

In this arm, participants will receive a 75-minute intraduodenal infusion of saline (an isotonic solution containing 2.8 g of sodium chloride (NaCl), dissolved in 225 mL of distilled water).

Other: Control

Interventions

Ca-1000 OTHER

Calcium, an essential mineral and a key component of dairy, is a regular part of our daily diet. Recent studies have shown that calcium, at doses of 1000 mg, stimulates gut hormones and motility, will be 'higher dose' in this condition.

Ca-1000

Ca-500 OTHER

Calcium, an essential mineral and a key component of dairy, is a regular part of our daily diet. Recent studies have shown that calcium, at doses of 500 mg, stimulates gut function. In this condition, it will be considered 'lower dose.'

Ca-500

Control OTHER

Saline (an isotonic solution containing 2.8 g of sodium chloride (NaCl), dissolved in 225 mL of distilled water).

Control

Eligibility Criteria

• Age: 18 Years - 70 Years
• Sex: male
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Males with type 2 diabetes mellitus (T2DM). Diagnosis of T2DM will be based on WHO criteria. Only males will be included to avoid the confounding effects of the menstrual cycle on gastric emptying.
• BMI: 28-38 kg/m².
• HbA1c \>=6.5 - \<=7.9% at screening.
• Blood glucose medications will be required to be withheld for 48 hours prior to each study day.
• Weight-stable (i.e. \<5% fluctuation) at study entry, which will be ascertained by a stable body weight in the preceding 3 months.

You may not qualify if:

• Significant GI symptoms, or history of GI disease or surgery
• Current gallbladder or pancreatic disease
• Cardiovascular or respiratory diseases
• Any other illnesses (except type 2 diabetes) as assessed by the investigator - (including chronic illnesses not explicitly listed above)
• Use of prescribed or non-prescribed medications (including vitamins and herbal supplements) which may affect energy metabolism, GI function, bodyweight 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)
• Individuals with low ferritin levels (\<30 ng/mL), or who have donated blood in the 12 weeks prior to taking part in the study
• High performance athletes
• Current intake of \> 2 standard drinks on \> 5 days per week (\>140g/week)
• Current smokers of tobacco (cigarettes, cigars, pipes, sheesha, chewing, vaping etc.)
• Current use of recreational drugs, e.g. marijuana
• Current intake of any illicit substance
• Vegetarians
• Inability to tolerate nasoduodenal tube
• Inability to comprehend study protocol

Sponsors & Collaborators

• University of Adelaide: lead

Study Sites (1)

Clinical Research Facility, Adelaide Health and Medical Sciences Building

Adelaide, South Australia, 5005, Australia

RECRUITING

Study Officials

• Prof Christine Feinle-Bisset

  Adelaide Medical School University of Adelaide Level 5 Adelaide Health and Medical Sciences Building, Cnr George St and North Tce, Adelaide, SA 5005

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Prof Christine Feinle-Bisset

CONTACT

+61 8 8313 6053; christine.feinle@adelaide.edu.au

Penelope Fitzgerald, MsC

CONTACT

+61883136278; penelope.fitzgerald@adelaide.edu.au

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: In order to blind both investigator and participant, the treatments will be prepared on the morning of each study day, by a research officer who will have no involvement in data analysis.
• Purpose: OTHER
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor Christine Feinle-Bisset

Study Record Dates

• First Submitted: April 8, 2025
• First Posted: April 24, 2025
• Study Start: May 22, 2025
• Primary Completion: March 28, 2026
• Study Completion: April 28, 2026
• Last Updated: December 26, 2025

Record last verified: 2025-04

Data Sharing

• IPD Sharing: Will not share

Locations

AU (1)