it does say something useful. it points out that iodine can't be synthesized in our bodies.
the fact it doesn't add more, possibly irrelevant, information does not diminish its usefulness.
it does not imply anything about things that aren't being discussed. it's abnormal to read everything with a qualification like "in our bodies" as a implication of some other hidden meaning.
as technical people we probably enjoy delving into tangents and pedantry far too much. but, for example, adding a statement "... In fact, iodine is an element and cannot be synthesized ... " would be a tangent and should be avoided or edited out.