Coffee impairs intestinal absorption of levothyroxine; report of additional cases
A Sindoni, R Vita, S Fusco, G Saraceno, MA Pappalardo, O-R Cotta, S Grasso, F Trimarchi, S Benvenga
Coffee interferes with the intestinal absorption of levothyroxine
We report another six adult patients, 5 women and 1 man, aged 38 to 62 years, who were observed during the last 18 months. All patients were referred because of failure of serum TSH to be normalized or suppressed by appropriate replacement (1.6-1.8 μg/kg b.w.) or TSH-suppressive (2.0-2.2 μg/kg b.w.) therapy with L-T4. In each of the six patients, serum TSH failed to be normalized or suppressed if L-T4 was swallowed simultaneously with coffee (or followed by coffee soon after).
Correction of this habit, by drinking coffee 60 minutes after having swallowed L-T4 with water, resulted in normalization or suppression of serum TSH.