Food and medicine interaction
Coffee, soy, walnuts and high-fiber foods and levothyroxine (Synthroid, Levoxyl, others)
EstablishedEvidence level: established. Shown in drug labeling or in controlled studies in people.
Last reviewed
What can happen
Taking levothyroxine with coffee lowered its absorption in a small controlled study (absorption measures fell by roughly 20 to 36 percent), and bran fiber interfered even more. MedlinePlus warns that soybeans, walnuts and dietary fiber may affect how levothyroxine works.
- Why it happens
- These foods can bind levothyroxine or reduce how much is absorbed from the gut.
- At ordinary food amounts
- Ordinary amounts matter when taken close to the dose. Waiting before coffee removed the effect in the study: coffee taken 60 minutes after the tablet gave results similar to water.
What to do
Take levothyroxine as directed, usually on an empty stomach 30 to 60 minutes before breakfast, and keep your routine consistent. Tell your prescriber if you change your coffee, soy or fiber habits, since your dose may need rechecking.
Never stop or change a prescribed medicine without talking to the prescriber.
Common questions
Can I have coffee, soy, walnuts and high-fiber foods while taking thyroid hormone?
Take levothyroxine as directed, usually on an empty stomach 30 to 60 minutes before breakfast, and keep your routine consistent. Tell your prescriber if you change your coffee, soy or fiber habits, since your dose may need rechecking. Ordinary amounts matter when taken close to the dose. Waiting before coffee removed the effect in the study: coffee taken 60 minutes after the tablet gave results similar to water.