[45] Nishiyama S,Futagoishi-Suginohara Y,Matsukura
M,Nakamura T,Higashi A,Shinohara M,others.
"Zinc supplementation alters thyroid hormone
metabolism in disabled patients with zinc deficiency."
Journal of the
Research reported by
Department of Pediatrics, Kumamoto University School of Medicine, Japan
Conclusion: Zn may play a
role in thyroid hormone metabolism in low T3 patients and may in part
contribute to conversion of T4 to T3 in humans.
Author's abstract:
OBJECTIVE: We examined zinc
(Zn) status in relation to thyroid function in disabled persons, because the
association between Zn deficiency and thyroid function remains controversial.
METHODS: After measuring serum free 3,5,3'-triiodothyronine (T3) and free thyroxine (T4) in 134
persons, TSH-releasing hormone (TRH) injection test and estimation of Zn status
were conducted in persons with low free T3.
RESULTS: Thirteen had low
levels of serum free T3 and normal T4. Patients with elevated levels of serum 3,3',5'-triiodothyronine (rT3) showed an enhanced reaction of
serum thyrotropin (TSH) after TRH injection.
Nine of 13 patients had mild to moderate Zn
deficiency evaluated by body Zn clearance and increased urinary Zn excretion.
After oral supplementation of Zn sulphate (4-10 mg/kg
body weight) for 12 months, levels of serum free T3 and T3 normalized,
serum rT3 decreased, and the TRH-induced TSH reaction normalized.
Serum selenium concentration
(Type 1 T4 deionidase contains selenium in the rat) was unchanged by Zn
supplementation.
Looks like zinc supplementation may help those with low FT3, and
a higher than normal ratio of RT3 to T3
to get their FT3 levels up and reduce that RT3:T3 ratio…now why do they have
increased Zn clearance causing this deficiency?