The Lactose Intolerance Clearinghouse Has Moved.

My old website can be found at I am no longer updating the site, so there will be dead links. The static information provided by me is still sound.

For quick offline reference, you can purchase Planet Lactose: The Best of the Blog as an ebook on or or or a whole lot of other places that Smashwords is suppose to distribute the book to. Almost 100,000 words on LI, allergies, milk products, milk-free products, and the genetics of intolerance, along with large helpings of the weirdness that is the Net.

I suffer the universal malady of spam and adbots, so I moderate comments here. That may mean you'll see a long lag before I remember to check the site and approve them. Despite the gap, you'll always get your say. I read every single one, and every legitimate one gets posted.

Wednesday, July 25, 2007

Serious Warning About Thyroid Medication

If you are taking high doses of the thyroid medication levothyroxine and the medication is not working properly, it may be because you are lactose intolerant.

This was the surprising news from a study in the medical journal Thyroid 2006, 16(11): 1171-1173. doi:10.1089/thy.2006.16.1171. The study, "Lactose Intolerance Revealed by Severe Resistance to Treatment with Levothyroxine," was by three Spanish researchers, Manuel Munoz-Torres, Mariela Varsavsky, and Guillermo Alonso.

Here's the abstract:

The most common cause of apparent ineffectiveness or resistance to treatment with oral levothyroxine (LT4) is the result of noncompliance, known as pseudomalabsorption. However, an abnormality in the bioavailability of LT4 should also be considered in patients requiring large doses of LT4 to achieve euthyroidism. The incidence of lactose intolerance in Caucasian adult patients is 7%–20%, but the association with resistance to treatment with oral LT4 is unusual. We report a 55-year-old woman in whom treatment LT4 for hypothyroidism was found related to a previously undiagnosed oligo-symptomatic lactose intolerance, an unusual association. Although rare, intolerance to lactose should be considered in the differential diagnosis of gastrointestinal diseases that can cause malabsorption of LT4. The possibility of correcting this disorder with simple dietary measures justifies its consideration.

Obviously, it you are taking levothyroxine, you should talk with your doctor just to be safe.

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1 comment:

Knight said...

Wow. Who would have thought it. Very interesting fact. I was lactose intolerant as a child but grew out of it by high school.