Iodine Deficiency
Conditions
Keywords
iodine, seaweed, supplementation, reformulation, food matrix, thyroid function
Brief summary
In this project, the investigators propose an intervention design testing the efficacy of a food reformulated with seaweed as an ingredient in meal, capsules against placebo and no intervention controls. The randomised control trial (supplementation) will last 24 weeks. The aim is to study the effect of the food matrix on variables associated with iodine nutrition: iodine status and thyroid function.
Detailed description
This study is a randomized, double-blind, placebo-controlled trial conducted in Glasgow, United Kingdom. Inclusion criteria are as follows: healthy premenopausal women aged 18 - 60 years who would remain a resident in Glasgow for 24 weeks; who were self-reported low iodine consumers consuming milk less than once per day and non-oily fish less than once per week. Those with a history of thyroid dysfunction, taking medications other than the contraceptive pill or smoking, as well as pregnant or lactating women and those planning to conceive, were excluded. Those taking dietary supplements containing iodine would also excluded and there was no restriction related to body mass index (BMI). Participants are recruited via social media and advertisements displayed around the Greater Glasgow area. Interested parties are screened and, if eligible, invited to a 30-minute appointment at which participants were randomly assigned through a web-based randomisation service to one of four groups after consent is obtained; reformulated pizza, control pizza, iodine capsules, or placebo capsules. During this initial meeting anthropometric measurements, blood pressure and a venous blood sample are collected, and participants are also asked to complete a sociodemographic questionnaire and an iodine specific food frequency questionnaire (FFQ). Participants are provided with instructions and equipment to record a 3-day estimated food diary and to collect 12 spot urine samples at different times of day over 2-7 days. Upon returning the spot urine samples, participants were given either the pizzas or supplements to begin the intervention. Participants are asked to consume one pizza or supplement three times a week for 24 weeks. Participants are asked to collect a further 10-12 sample spot urine samples at week 2 of the intervention. Participants are asked to attend another 30-minute appointment at 12 and 24 weeks in which baseline measurements are repeated along with a change to diet questionnaire.
Interventions
DIETARY_SUPPLEMENTReformulated pizza
Reformulated food with 400ug of iodine per meal, three times per week (to achieve 122% of weekly recommended intakes - average 140ug/day).
DIETARY_SUPPLEMENTControl pizza
Control (placebo) meal to consume thrice weekly (no iodine supplementation).
DIETARY_SUPPLEMENTSeaweed capsule
Capsules containing seaweed extract, the iodine-rich ingredient in the reformulated pizza, 400ug iodine per capsule, to be consumed three times per week (122% of weekly recommended intake).
DIETARY_SUPPLEMENTControl capsule
Empty capsules (placebo)
Sponsors
University of Glasgow
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
DOUBLE (Subject, Investigator)
Masking description
Masking of pizzas was achieved by the use of pizzas with identical appearance and taste. Iodine and control supplements were also identical in appearance. Both pizzas and supplements were provided to investigators already masked. Pizzas labelled X and Y. Supplements labelled A and B
Intervention model description
Randomized, double-blind, placebo-controlled trial
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 60 Years
Healthy volunteers
Yes
Inclusion criteria
* self-reported healthy women * aged 18 to 60 * pre-menopausal * with no history of thyroid dysfunction * without any known allergic reactions to foods * not on medication that impact on absorption of nutrients from the gut * not currently taking dietary / multivitamin supplements (must have discontinued usage 2 weeks prior the start of the study)
Exclusion criteria
* pregnancy * lactation * habitual consumption of seaweed-based products (\>once per week), milk (\>once per day), sea fish, non-oily, e.g. cod (\>once per week) * veganism (as food products contains cheese) * Involvement in another research study where diet is restricted, modified, or dietary habits are studied. * women who have reached menopause.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in urinary iodine concentration (UIC) | 0, 12 weeks | Change in UIC assessed in pooled spot urine samples at 12 weeks, from baseline |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Concentration of thyroid stimulating hormone | 0, 12, 24 weeks | measured by immunoassay |
| Concentration of Free Triiodothyronine | 0, 12, 24 weeks | measured by immunoassay |
| Concentration of Thyroxine | 0, 12, 24 weeks | measured by immunoassay |
| Dietary iodine intake | 0, 12, 24 weeks | estimated by food frequency questionnaire (FFQ) |
| Change in urinary iodine concentration (UIC) | 0, 2 weeks | Change in UIC assessed in pooled spot urine samples at 2 weeks, from baseline |
| Changes in body weight | 0, 12, 24 weeks | Changes in body weight assessed from baseline at 12 and 24 weeks |
| Changes in body mass index | 0, 12, 24 weeks | Changes in body mass index assessed from baseline at 12 and 24 weeks |
| Changes in waist circumference | 0, 12, 24 weeks | Changes in waist circumference assessed from baseline at 12 and 24 weeks |
| Concentration of thyroglobulin | 0, 12, 24 weeks | measured by immunoassay |
Other
| Measure | Time frame | Description |
|---|---|---|
| concentration of HDL/LDL cholesterol | 0, 12, 24 weeks | measured in blood |
| glucose concentration | 0, 12, 24 weeks | measured in blood |
| concentration of total cholesterol | 0, 12, 24 weeks | measured in blood |
| concentration of triglycerides | 0, 12, 24 weeks | measured in blood |
Countries
United Kingdom
Outcome results
None listed