A note for those who take thyroid hormone...
We work with many folks who experience frustration because their thyroid dose never seems to be stable.
"Every time I get my blood drawn, it seems my dose needs adjustment!"
While there are many factors that can affect the reliability of the dose, some basics that help to keep your levels stable are to:
- Take the thyroid hormone on an empty stomach, ideally 45 minutes before eating and 2-3 hours after eating
- Avoid taking calcium, vitamins, antacids, iron, or soy products at the same time as thyroid hormone
- Avoid certain medications known to interfere with thyroid hormone absorption (sertraline, raloxifene, colestipol, sucralfate, fiber supplements) at the same time as the thyroid medication
- Stick with the same brand of thyroid hormone for consistency, or for generic versions try to stick with one manufacturer
- Stop high dose biotin supplements for 3 days before blood testing, as high dose biotin (above the RDA) can cause inaccurate thyroid blood test results
This month an interesting article was published in Frontiers in Endocrinology showing that both coffee and tea, when consumed within one hour of taking thyroid hormone, interfered with the absorption of thyroid hormone.
Shown below in the first figure is the TSH level at (1) baseline, (2) when drinking coffee or tea or both within one hour of thyroid hormone ingestion, and (3) when separating these drinks by 4 hours from the thyroid hormone. You'll notice the TSH rose substantially when they were consumed together, indicating decreased absorption of thyroid hormone.