Sentence:  In the presence of a low <WSD>iodine</WSD> intake , thyroglobulin labelled in vivo with * * f is found to contain more mono-iodotyrosine than normal , the amounts of di-iodotyrosine and iodothyronines being correspondingly reduced . 
Meaning of the word marked with <WSD> tags:  a nonmetallic element belonging to the halogens; used especially in medicine and photography and in dyes; occurs naturally only in combination in small quantities (as in sea water or rocks)