Inclusion Criteria:  Healthy Male or female Aged 18-48 Signed informed consent  Exclusion Criteria:  Pregnancy and lactation Past and present thyroid conditions Diseases of the gastrointestinal tract Allergy to seafood or dairy Consumption of iodine supplements Currently taking medication (other than the contraceptive pill) Having a habitual diet very low in iodine (<1 portion of dairy per day, or < 1 portion of fish per week)