Bioavailability of Iodine in Cow's Milk in Swiss Adults

NCT03590431 | Completed

• 1 other identifier: BICOM 2018-00130
• Study Type: interventional
• Target: 12
• Locations: 1 country
• Sites: 1

Brief Summary

Iodine deficiency remains a global problem impairing health and development in affected populations. Although there has been remarkable global progress against iodine deficiency, mild and moderate iodine deficiency remain common globally, including European countries. Besides salt, milk and dairy products are important iodine sources in many industrialized countries, with varying contributions depending on the milk iodine concentration and the amount of milk and dairy consumed. Iodine absorption in humans depends on the iodine species and possibly on the iodine status of the person. Very little data is available on iodine absorption or bioavailability from different dietary sources including milk. Inorganic iodide is thought to be absorbed almost completely (\>90%). In contrast, only about two-thirds of some forms of organically-bound iodine are absorbed. The absorption of iodine from milk has not been quantified in humans. In this balance study, the investigators want to quantify the absorption of iodine in cow's milk in male and female adults and compare with the bioavailability from an iodine water solution (potassium iodide). The results of this study will inform on the bioavailability rate of iodine from cow's milk. Knowing the actual iodine bioavailability from milk is critical because milk and dairy products are major iodine sources in many industrialized countries. The primary objective of this randomized, cross-over design study is to assess iodine bioavailability (measured using excretion in urine) from whole cow's milk delivering an iodine level of about 600 µg/L and compare them with a control iodine solution. The investigators will test three drinks within one subject: 1) a milk with an intrinsic iodine concentration of about 600 µg/L; 2) a milk with a naturally low iodine concentration and an added amount of potassium iodide (extrinsic iodine in milk matrix) to reach a level of about 600 µg/L (adapted to the intrinsic concentration in 1)); and 3) control iodine solution (extrinsic iodine in water matrix) with the same iodine concentration.

Conditions

Iodine Bioavailability

Keywords

iodine; bioavailability; milk

Outcome Measures

Primary Outcomes (1)

• Iodine concentration in urine

  measured by Sandell-Kolthoff method, mikrograms per liter To calculate iodine absorption, excretion and retention.

  Days 1, 2, 3, 8, 9, 10, 15, 16 and 17

Secondary Outcomes (3)

• TSH

  day 1

• T4

  day 1

• iodine content of standardized diet

  prior to study start

Other Outcomes (2)

• Age

  at screening

• BMI

  at screening

Study Arms (3)

bioavailability iodine milk (extrinsic)

OTHER

300 ml whole cow's milk delivering ≈ 200 µg iodine (extrinsic iodine in milk, low protein-bound fraction)

Dietary Supplement: extrinsic iodine in milk

bioavailability iodine milk (intrinsic)

OTHER

300 ml whole cow's milk delivering ≈ 200 µg iodine (intrinsic iodine in milk, high protein-bound fraction)

Dietary Supplement: intrinsic iodine in milk

bioavailability water iodine solution

OTHER

300 ml water iodine solution delivering ≈ 200 µg iodine (water iodine solution)

Dietary Supplement: water iodine solution

Interventions

extrinsic iodine in milk DIETARY_SUPPLEMENT

300 ml whole cow's milk delivering ≈ 200 µg iodine (extrinsic iodine, low protein-bound fraction) The whole cow's milk will be produced in an experimental barn feeding supplementary iodine to reach a final iodine concentration of ≈ 50 µg/L. The iodine content of the extrinsically labelled milk will be adjusted to the required concentration (same as intrinsic iodine milk) by adding iodine in form of potassium iodide.

bioavailability iodine milk (extrinsic)

intrinsic iodine in milk DIETARY_SUPPLEMENT

300 ml whole cow's milk delivering ≈ 200 µg iodine (intrinsic iodine, high protein-bound fraction) The whole cow's milk will be produced in an experimental barn feeding supplementary iodine to reach a final iodine concentration of ≈ 600 µg/L. This concentration will define final supplemental iodine given to the participants (adapting the total portion size).

bioavailability iodine milk (intrinsic)

water iodine solution DIETARY_SUPPLEMENT

300 ml water delivering ≈ 200 µg iodine (control)

bioavailability water iodine solution

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Aged between 18 and 45 years
• BMI 19-25 kg/m2
• Current use of iodized salt at home
• Signed informed consent

You may not qualify if:

• Inadequate iodine status (defined as UIC \<70 µg/L or \>300 µg/L and assessed during screening from 5 urine spot samples)
• Exposure to iodine-containing X-ray/ computed tomography contrast agent
• Use of iodine-containing disinfectants (betadine)
• 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)
• Chronic use of medications (except for contraceptives)
• Use of iodine containing supplements within 1 month prior to study start
• Pregnancy (according to the participants own statement but confirmed by a pregnancy test with the first urine spot sample from screening)
• Breast feeding
• Vegan diet
• Drug abuse
• Extensive alcohol intake, defined as more than 3 (men) or 2 (women) standard drinks per day (i.e. 3dl beer, 1dl wine, 3-4cl liquor), with less than 2 days per week without alcohol consumption

Sponsors & Collaborators

• Isabelle Herter-Aeberli: lead

Study Sites (1)

ETH Zürich

Zurich, 8092, Switzerland

Location

Related Publications (1)

• van der Reijden OL, Galetti V, Burki S, Zeder C, Krzystek A, Haldimann M, Berard J, Zimmermann MB, Herter-Aeberli I. Iodine bioavailability from cow milk: a randomized, crossover balance study in healthy iodine-replete adults. Am J Clin Nutr. 2019 Jul 1;110(1):102-110. doi: 10.1093/ajcn/nqz092.

  PMID: 31788697 DERIVED

MeSH Terms

Interventions

Milk

Intervention Hierarchy (Ancestors)

Beverages; Diet, Food, and Nutrition; Physiological Phenomena; Dairy Products; Food; Food and Beverages

Study Officials

• Isabelle Herter-Aeberli, Dr.

  University of Zurich

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Masking Details: Two of the three test drinks will consist of milk delivering extrinsic iodine or intrinsic iodine and will appear the same. These two milks will be labelled with "A" and "B" and masking will be applied to the participant only (single-blinded). The code will be held by the Study coordinator. However, for the water iodine-solution, blinding will not be possible.
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Principal Investigator

Study Record Dates

• First Submitted: May 30, 2018
• First Posted: July 18, 2018
• Study Start: June 18, 2018
• Primary Completion: September 27, 2018
• Study Completion: September 27, 2018
• Last Updated: March 8, 2019

Record last verified: 2019-01

Locations

CH (1)