Bioavailability of Iodine in Cow's Milk in Swiss Adults
Condition: Iodine Bioavailability
Study type: Interventional

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.
    


Intervention name(s): extrinsic iodine in milk; intrinsic iodine in milk; water iodine solution
Intervention type(s): Dietary Supplement; Dietary Supplement; Dietary Supplement
Intervention description(s): 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.; 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).; 300 ml water delivering ≈ 200 µg iodine (control)
Intervention MeSH terms: Iodine; Cadexomer iodine
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Participant)
Primary purpose: Basic Science
Keywords: iodine; bioavailability; milk