Evidence check: TSH Schilddrüse in the context of Darmgesundheit

The provided context does not contain specific information about EFSA lowering the selenium upper limit to 255 µg/day. In general, EFSA reduced the tolerable upper intake level (UL) for selenium from 300 to 255 µg/day in 2023, citing evidence from human studies linking long-term high intake to increased risk of type 2 diabetes and selenosis. However, since this detail is absent from the given knowledge base, I cannot confirm it from the provided sources. The evidence level is therefore unclear. For accurate guidance, refer to the original EFSA scientific opinion (e.g., EFSA Journal 2023). Caveat: always consider dietary selenium sources and consult a healthcare professional before taking supplements.