Lay opinion vs evidence: TSH Ernährung

The relationship between TSH and nutrition is often discussed, but the evidence is nuanced. It is well-established that adequate iodine and selenium intake are essential for normal thyroid function. Iodine deficiency can raise TSH, and selenium deficiency can impair T4-to-T3 conversion. However, extreme diets or isolated supplements (e.g., high-dose iodine) in euthyroid individuals are usually not beneficial and may be harmful. Claims that specific foods (e.g., cruciferous vegetables) significantly lower or raise TSH are not strongly supported by evidence. Factors like stress, sleep deprivation, or medications often have a greater impact. If TSH is abnormal, a full thyroid workup (including fT3, fT4, antibodies) is necessary before recommending dietary changes. Overall evidence is moderate, as many recommendations are based on observational studies or extrapolations from deficiency regions.