glutathione is the master antioxidant Do You Know About Antioxidant? Glutathione & Thyroid Health: The
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Martos et al., 2017

Further human clinical research is needed before definitive conclusions can be made
Additionally, deficiencies in selenium and zinc, commonly observed in restrictive diets, can impair antioxidant defense (via glutathione peroxidase) and reduce deiodinase function, further diminishing thyroid hormone activation [105]
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Low plasma vitamin B12 concentrations are common in patients with cancer
