Caring Medical
& Rehabilitation Services
715 Lake Street, Suite 600
Oak Park, Illinois 60301
708.848.7789 Phone
708.848.7763 Fax

Soy, Calcium, and Synthroid

Our Nutritionist's Question:
I have been doing some research on soy and calcium affecting the drug synthroid. There are a lot of rumors stating that you cannot have soy and synthroid at the same time because the soy keeps the body from absorbing the synthroid, which would allow the synthroid to help the thyroid. I can’t find any facts and research studies on the internet that prove soy and calcium do affect the drug. So I went a head and told a patient that she can eat soy and have calcium anytime she wants and does not have to wait a few hours in between the two. Do you know anything about synthroid and soy/calcium? I just want to make sure I told the patient the right thing. I looked on your past articles and could not find anything.

Answer:
There is nothing I know of (except the anti-thyroid drugs) that will block the effect of thyroid hormone replacement. I'm sure thousands of my thyroid patients have taken both calcium and soy together with their medication without any problem. Monitoring with TSH levels means I am quite sure there is not a problem.

There is an "anti-soy" group out there, probably a backlash to all the hype about soy early on. Truth (as usual) is somewhere in between. Soy is neither a devil nor an angel. It's just a food.

Whatever "they" are saying about soy and calcium and thyroid replacement, well it's just not true.