Certainly this is NOT the last word on the subject. The conclusion is "not enough evidence".
It is, of course, important that this is not taken as evidence against!
Selenium supplementation for Hashimoto's thyroiditis
Hashimoto's thyroiditis is a common disease in which a form of chronic inflammation of the thyroid gland results in reduced function of the gland. It is an auto-immune disorder, which means that a person's own immune system attacks the thyroid gland, so that it no longer makes adequate quantities of thyroid hormones (hypothyroidism). Common clinical manifestations include feeling cold, depressive mood, dry skin, puffy eyes, constipation, weight gain, slowed heart rate, joint and muscle pain and fatigue. Some but not all people with Hashimoto's thyroiditis have an enlarged gland, also called a goitre. Hashimoto's thyroiditis is more common in women than in men and tends to run in families. Other auto-immune diseases often occur simultaneously, such as vitiligo, rheumatoid arthritis and diabetes type 1. The disease does not always require treatment, but when it does, it is treated with synthetic thyroid hormone replacement (sometimes desiccated thyroid hormone is used, which is not synthetic). Selenium is an essential trace element that is required in small amounts for correct functioning of the immune system and the thyroid gland.
Four studies at unclear to high risk of bias comprising 463 participants were included. The mean study duration was 7.5 months (range 3 to 18 months). None of the studies addressed our key primary outcome-'health-related quality of life'. Two of our secondary outcomes-'change from baseline in levothyroxine (i.e. thyroid hormone) replacement dosage at end of the study' and 'economic costs'-were not assessed either. One study at high risk of bias showed a statistically significant improvement in subjective well-being with sodium selenite 200 µg plus levothyroxine compared with placebo plus levothyroxine (14/18 compared with 3/18, respectively). Selenomethionine 200 µg and sodium selenite 200 µg reduced the serum levels of anti-thyroid peroxidase antibodies in three studies, and although the changes from baseline were statistically significant, their clinical relevance is unclear. Adverse events were reported in two studies, and selenium supplementation did not lead to more adverse events than were seen with placebo. One adverse event was reported in both studies in the selenomethionine 200 µg plus LT4 arm versus none in the control arm.
In conclusion, the results of these four studies do not provide enough evidence to support the use of selenium in the treatment of Hashimoto's thyroiditis.
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