Establishing the Glycaemic Index of Vegetable Smoothies

NCT07729631 | Completed

• 1 other identifier: 10814-13276
• Study Type: interventional
• Target: 16
• Locations: 1 country
• Sites: 1

Brief Summary

Glycaemic responses to carbohydrates ingested as fruit and vegetables may vary depending on factors inherent to the fruit or vegetable, and on the type of sugar. The aim of this project is to investigate the glycaemic responses to two new fruit and vegetable smoothies, and to establish the glycaemic index for each product relative to a glucose reference. Participants will undertake 4 postprandial tests with 2 different test drinks following best practice guidelines for glycaemic index testing. The test drinks (GREEN and RED) will be matched for carbohydrate to the glucose reference (CONTROL) which will be sampled two times. Fingerstick capillary blood sampling will measure glucose concentrations. These data will provide insight into how differing formulations can alter the glycaemic responses to fruit and vegetable drinks.

Conditions

Glycaemic Index; Glycaemic Response; Glycaemic Response Measurements

Keywords

Vegetable Smoothies; Glycaemic Index

Outcome Measures

Primary Outcomes (1)

• Glycaemic indices for 2 test drinks measured using capillary blood samples

  Glycaemic indices \[2-hour incremental area under the glucose curve (mmol/L-1x120 minutes) for each of the 2 test drinks relative to mean value of control conditions (CONTROL, REPLICATE CONTROL), expressed as a percentage\] in capillary blood samples

  120 minutes

Other Outcomes (4)

• Comparisons between conditions in glucose concentration in capillary samples

  120 minutes

• Comparisons between conditions in glucose concentration in capillary samples

  120 minutes

• Comparisons between conditions in glucose concentration in capillary samples

  120 minutes

Study Arms (4)

CONTROL

ACTIVE COMPARATOR

50 g glucose (55 g dextrose powder accounting for hydration) plus 519 mL water

Other: Vegetable Smoothie

REPLICATE CONTROL

ACTIVE COMPARATOR

50 g glucose (55 g dextrose powder accounting for hydration) plus 519 mL water

Other: Vegetable Smoothie

RED

EXPERIMENTAL

500 mL of commercially available "Red Goodness" providing 50 g of carbohydrate \[apple (47%), banana, chayote (8%), beetroot (7%), carrot (5%), cucumber (5%), cherry (3%), spinach (2%), mandarin, lemon, apple water, beetroot extract\]. Plus 19 mL water to standardise volume

Other: Vegetable Smoothie

GREEN

EXPERIMENTAL

519 mL of commercially available "Green Goodness" smoothie providing 50 g carbohydrate \[apples (46%), banana, courgette (10%), chayote (8%), guava, cucumber (5%), lemon (3%), spinach (2%), mandarin, apple water spirulina extract, turmeric extract, mint extract\].

Other: Vegetable Smoothie

Interventions

Vegetable Smoothie OTHER

Commercially available fruit and vegetable smoothie

CONTROL

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age: 18-65 years
• Body mass index 18-30 kg/m2

You may not qualify if:

• diagnosis of any form of diabetes
• intolerances or allergies to any of the study procedures (e.g. fructose/inulin intolerance)
• Fructose malabsorption
• Inborn errors of fructose metabolism (e.g. fructokinase deficiency, aldolase B deficiency, fructose-1,6-bisphosphatase deficiency)
• pregnant or lactating
• any condition that could introduce bias to the study (e.g. diagnoses of lipid disorders, including cardiovascular disease, or therapies that alter lipid or glucose metabolism, such as statins or niacin).

Sponsors & Collaborators

• University of Bath: lead

Study Sites (1)

Department for Health, University of Bath

Bath, BA2 7AY, United Kingdom

Location

Related Publications (2)

• Brouns F, Bjorck I, Frayn KN, Gibbs AL, Lang V, Slama G, Wolever TM. Glycaemic index methodology. Nutr Res Rev. 2005 Jun;18(1):145-71. doi: 10.1079/NRR2005100.

  PMID: 19079901 BACKGROUND

• Gonzalez JT. Are all sugars equal? Role of the food source in physiological responses to sugars with an emphasis on fruit and fruit juice. Eur J Nutr. 2024 Aug;63(5):1435-1451. doi: 10.1007/s00394-024-03365-3. Epub 2024 Mar 16.

  PMID: 38492022 BACKGROUND

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: PhD Researcher

Model Details: Randomised, controlled crossover trial

Study Record Dates

• First Submitted: July 22, 2026
• First Posted: July 27, 2026
• Study Start: October 22, 2025
• Primary Completion: December 15, 2025
• Study Completion: December 15, 2025
• Last Updated: September 22, 2026

Record last verified: 2026-09

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF
• Time Frame: These will become available at the point of publication permanently

Locations

GB (1)