Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT04867031 |
| Other study ID # |
200160161 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
August 26, 2017 |
| Est. completion date |
July 3, 2018 |
Study information
| Verified date |
January 2023 |
| Source |
University of Glasgow |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
This study is a randomized crossover trial, lasting 12 days in total, which will assess the
difference in iodine bioavailability (as a percentage of iodine consumed that is excreted in
urine) from three iodine-rich foods; semi-skimmed milk, white fish, and dried seaweed sheets.
Each of the three foods will provide approximately 140µg of iodine, and iodine excretion will
be monitored for 36 hours following food ingestion via collection and analysis of urine.
Description:
Iodine insufficiency is one of the three key micronutrient deficiencies highlighted as major
public health issues by the World Health Organisation, and recent evidence indicates that the
UK is now iodine deficient. Iodine deficiency represents a particular threat for women of
child-bearing age, unborn infants and young children, as iodine is essential to synthesise
the thyroid hormones, which are involved in key metabolic function including fetal brain
development. Maternal iodine deficiency and the resulting changes in thyroid function has
been associated with adverse pregnancy outcomes including spontaneous miscarriage, fetal
distress and death, preterm delivery, low birth weight and impaired neuropsychological
development, with significant impact on later life development and quality of life.
There is no iodine fortification programme in the United Kingdom, and despite worldwide
efforts to tackle iodine deficiency and associated disorders via iodine supplementation and
food-fortification (of salt mainly), consumption of supplements in the UK is virtually
non-existent, with iodised salt used by less than 5%.
In the UK, the main dietary sources of iodine are dairy and sea-foods. Our previous studies
have shown that seaweed intake can increase the iodine status of women with diets habitually
low in iodine. Reduced bioavailability of iodine from the seaweed matrix, which could have
implications for dietary recommendations.
This study address the influence of the food matrix on iodine bioavailability, in the context
of food guidelines and assessment of the iodine status.
This project is in collaboration with the British Broadcast Corporation (BBC).
The study design is a crossover randomised trial - to last 9 days, plus three days pre-trial
washout [total 12 days] - with 3 arms:
1. fish arm: portion equivalent to 140 µg iodine, approx. 130g.
2. milk arm: portion equivalent to 140 µg iodine, approx. 450mL.
3. seaweed arm: portion equivalent to 140 µg iodine, approx. 6g.
Each arm will be separated by two washout days, and participants will follow a low iodine
diet (avoiding dairy, and all seafood) throughout the study, as well as three days prior to
the first arm. Iodine levels will be monitored in urine collected during the 12 hours
preceding and 36 hours following the meal. Urine will be collected in time fractions
A parallel design study showed that 56% (SD 20%) of a dose of potassium iodide is excreted
after 24hours, compared to 36% (SD 13%) when the same dose comes from seaweed. In order to
detect a similar difference, a sample of at least 13 participants is required (n=19 to allow
for 30% attrition).
