Bioavailability of Iodine in Cow's Milk in Swiss Adults

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

Interventions

DIETARY_SUPPLEMENT

extrinsic iodine in milk

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.

DIETARY_SUPPLEMENT

intrinsic iodine in milk

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).

DIETARY_SUPPLEMENT

water iodine solution

300 ml water delivering ≈ 200 µg iodine (control)

Sponsors & Collaborators

• Isabelle Herter-Aeberli

  lead OTHER

Principal Investigators

• Isabelle Herter-Aeberli, Dr. · University of Zurich

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

SINGLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

45 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2018-06-18

Primary Completion

2018-09-27

Completion

2018-09-27

Countries

• Switzerland

Study Locations