Effect of Low Dose Galactose on Glycaemia and Glucose Kinetics (GLOWS)

EFFECT OF LOW DOSE GALACTOSE ON GLYCAEMIA AND GLUCOSE KINETICS

This project will establish the degree to which adding low-dose galactose to a meal can control blood sugar levels. People will consume standardised glucose drinks (75g glucose, as an oral glucose tolerance test). People will consume these with and without the addition of galactose, and with the addition of another sugar (fructose) for an extra comparison. We will use state-of-the-art labelling methods (dual stable isotope technology) to follow what happens to the glucose that is ingested and understand what happens to sugar being released by the liver and sugar being taken up by other tissues like the muscles. These methods can tell us how the addition of galactose can control blood sugar levels. For example, the galactose could slow down the appearance of glucose from the gut and/or liver released into the blood, or it could increase the disappearance of glucose from the blood into muscles. We will measure the appearance of our label on exhaled breath, which will establish whether ingested sugar is stored, or burned as fuel. We will also explore other potential ways in which galactose might control blood sugar levels by measuring key hormones and metabolites that contribute to blood sugar control (for example, insulin, fatty acids, and incretin hormones which potentiate insulin secretion). This additional evidence of how galactose can control blood sugar levels will provide the understanding required to best make use of this approach across a variety of settings.

Study Overview

• Status: Recruiting
• Conditions: Glucose
• Intervention / Treatment: Dietary supplement: Glucose Powder; Dietary supplement: galactose; Dietary supplement: fructose

• Study Type: Interventional
• Enrollment (Estimated): 25
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Lucy Merrell, PhD; Phone Number: +441225385518; Email: lhm31@bath.ac.uk
• Study Contact Backup: Name: Javier T Gonzalez, PhD; Phone Number: +441225385518; Email: j.t.gonzalez@bath.ac.uk

Study Locations

• United Kingdom
  • Bath, United Kingdom
    • Recruiting
    • University of Bath
    • Contact: Lucy Merrell; Phone Number: +441225385518; Email: Lhm31@bath.ac.uk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age: 18 years and above;
• Normoglycaemic (fasting glucose <6.1 mmol/L)
• Body mass index: 18.5-30 kg/m2

Exclusion Criteria:

• weight instability (>5% change within last 3 months);
• pregnant or lactating;
• following a very low-carbohydrate (ketogenic) diet;
• diagnosis of diabetes or prediabetes, or any other metabolic disease;
• dietary intolerances or allergies, or to any other study procedures;
• disorders in the ability to metabolise galactose or fructose (e.g., galactosemias);
• diagnosis of any gastrointestinal disorders;
• any other condition/medications that could introduce bias;
• unable to understand and follow study procedures

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Sham Comparator: CONTROL; 75 g oral glucose tolerance test	Dietary supplement: Glucose Powder; 75 g glucose
Experimental: GALACTOSE; 75 g oral glucose tolerance test plus 7.5 g galactose	Dietary supplement: Glucose Powder; 75 g glucose; Dietary supplement: galactose; 7.5 g galactose
Active Comparator: FRUCTOSE; 75 g oral glucose tolerance test plus 7.5 g fructose	Dietary supplement: Glucose Powder; 75 g glucose; Dietary supplement: fructose; 7.5 g fructose

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Glucose incremental area under the curve	Difference in glucose concentration incremental area under the curve between treatments over a 180-minute postprandial period.	180 minutes
Plasma glucose kinetics	Difference in plasma glucose kinetics (rate of total glucose appearance, rate of endogenous glucose appearance, rate of exogenous glucose appearance, rate of glucose disappearance and glucose metabolic clearance rate) between treatments over a 180-minute postprandial period.	180 minutes
Oxidative and non-oxidative fate of ingested glucose	Difference in oxidative and non-oxidative fate of ingested glucose between treatments over a 180-minute postprandial period.	180 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Glucoregulatory and metabolite concentrations	Difference in glucoregulatory hormone and metabolite incremental area under the curve between treatments over a 180-minute postprandial period, with the following metabolites and hormones: Insulin, C-peptide Glucagon, Glucose-dependent insulinotropic polypeptide (GIP), Glucagon-like peptide-1 (GLP-1), Non-esterified fatty acids (NEFA), Glycerol, Uric acid, Triacylglycerol. Oxygen saturation, pH, Bicarbonate.	180 minutes
Whole-body carbohydrate and fat oxidation	Difference in whole-body carbohydrate and fat oxidation rates between treatments over a 180-minute postprandial period.	180 minutes

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Other analyte concentrations	Difference in hormone and analyte concentrations during the postprandial period, adjusted for baseline, with the following analytes: Fructose Galactose Low-density lipoprotein cholesterol High-density lipoprotein cholesterol C-reactive protein Aspartate transaminase Alanine aminotransferase	180 minutes

Collaborators and Investigators

• Sponsor: University of Bath
• Collaborators: University of Birmingham; Arla Foods

Publications and helpful links

General Publications

• Watkins J, Simpson A, Betts JA, Thompson D, Holliday A, Deighton K, Gonzalez JT. Galactose Ingested with a High-Fat Beverage Increases Postprandial Lipemia Compared with Glucose but Not Fructose Ingestion in Healthy Men. J Nutr. 2020 Jul 1;150(7):1765-1772. doi: 10.1093/jn/nxaa105.

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2026
• Primary Completion (Estimated): December 31, 2028
• Study Completion (Estimated): December 31, 2029

Study Registration Dates

• First Submitted: May 14, 2026
• First Submitted That Met QC Criteria: May 14, 2026
• First Posted (Actual): May 20, 2026

Study Record Updates

• Last Update Posted (Actual): May 20, 2026
• Last Update Submitted That Met QC Criteria: May 14, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Carbohydrates; Sugars; Hexoses; Monosaccharides; Ketoses; Galactose; Fructose
• Other Study ID Numbers: 5530-15133; UKRI/BB/C001910/1 (Other Grant/Funding Number: BBSRC and Arla Foods Ingredients)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: IPD will be shared via the University of Bath data repository in deidentified form at the point of publication of the primary outcome in a peer-reviewed journal.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No