The Bioavailability of Iodine in Plant-based Milk Alternatives (IoBIO)

Iodine is a mineral commonly found in seafood and dairy products such as milk and cheese. Iodine is important as it is required to make thyroid hormones which regulate growth and metabolism at all stages of life. The UK population has been iodine-sufficient for many years, however, there is now concern that iodine deficiency may be more prevalent than previously thought. This is a concern because iodine deficiency during pregnancy can result in cognitive impairment and developmental delays in children.

This study will to measure the ability to absorb iodine from plant-based milk alternatives fortified with iodine and compare with cow's milk in adults. Knowing the actual iodine bioavailability from plant-based alternatives is important because plant-based milk alternatives are becoming increasingly popular, especially in young adults, and are used as a replacement for cow's milk.

In this study, participants will consume three test drinks (cow's milk, soya milk and oat milk), one per week. The study will start with the cows' milk and the other two drinks will be administered in a random order with a crossover design. We will ask participants to follow a low iodine diet for three days leading up to the test day where they will drink one of the test drinks. Participants will then keep a food diary and collect their urine for the following 24 hours. Participants will then go back to their usual diet for at least four days before starting the next arm of the study with another test drink. This data will be used to calculate how much iodine was absorbed.

Study Overview

• Status: Active, not recruiting
• Conditions: Iodine Deficiency
• Intervention / Treatment: Dietary supplement: Cow's milk; Dietary supplement: Oat milk; Dietary supplement: Soya milk

• Study Type: Interventional
• Enrollment (Estimated): 17
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Guildford, United Kingdom, GU2 7XH
    • University of Surrey

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Self-reported healthy adults
• Aged 18+
• English speakers
• Signed consent form
• No allergies or intolerances to the study drinks
• Not following a vegan diet (participants will be required to drink cow's milk)

Exclusion Criteria:

• Pregnancy or lactating (according to the participants own statement)
• Living outside of the UK
• Involvement in another research study where diet is restricted or modified
• History of thyroid disease (according to the participants own statement)
• Any metabolic, gastrointestinal or chronic disease such as diabetes, hepatitis, hypertension, or cancer (according to the participants own statement)
• Use of iodine containing supplements within 1 week prior to study start
• Inadequate (<70 µg/day) or excessive (>500 µg/day) iodine intake from food (assessed during screening with previously validated iodine-specific FFQ)
• Use of iodine-containing disinfectants (betadine)
• Exposure to iodine-containing X-ray/ computed tomography contrast agent within the last month

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Cow's milk; Semi-Skimmed UHT Milk (estimated iodine concentration: 350 µg/L) providing approximately 200 µg of iodine (approx. 570mL).	Dietary supplement: Cow's milk; Participants will consume one portion of semi-skimmed cow's milk which will provide approximately 200 µg of iodine
Experimental: Oat milk alternative; Oat Drink (estimated iodine concentration: 370 µg/L) providing approximately 200 µg of iodine (approx. 545mL).	Dietary supplement: Oat milk; Participants will consume one portion of plant-based milk alternative (oat) which will provide approximately 200 µg of iodine
Experimental: Soya milk alternative; Soya Drink (estimated iodine concentration: 460 µg/L) providing approximately 200 µg of iodine (approx. 435mL).	Dietary supplement: Soya milk; Participants will consume one portion of plant-based milk alternative (soya) which will provide approximately 200 µg of iodine

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Urinary iodine excretion	1 sport urine sample will be collected the day before test drink consumption and a 24-hour urine sample will be collected following the test drink consumption.	A single spot-urine sample collected on days: 2, 9, 16 Urine collected for 24 hours after consumption of test drink on days: 3, 10, 17

Collaborators and Investigators

• Sponsor: University of Surrey

Study record dates

Study Major Dates

• Study Start (Actual): July 1, 2024
• Primary Completion (Estimated): July 1, 2025
• Study Completion (Estimated): August 1, 2025

Study Registration Dates

• First Submitted: January 3, 2025
• First Submitted That Met QC Criteria: January 9, 2025
• First Posted (Actual): March 25, 2025

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: January 9, 2025
• Last Verified: January 1, 2025

More Information

Terms related to this study

• Keywords: milk; iodine; plant-based; iodine bioavailability
• Other Study ID Numbers: FHMS 23-24 161 EGA

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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