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Cow’s Milk- Decreasing your body’s ability to absorb thyroid hormone medication

October 11th, 2017

Are you diagnosed or know someone with an under-active thyroid?

Results presented at ENDO 2017 from a recent preliminary study showed that cow’s milk acts as a barrier to how well the body absorbs Levothyroxine, significantly decreasing the body’s ability to absorb this common hormone medication.  This means that patients who take Levothyroxine and also drink cow’s milk may not be receiving the full benefits or dosage prescribed.

Levothyroxine is prescribed for patients with an underactive thyroid to replace the natural thyroid hormone thyroxine. Primary investigator Deborah Chon, M.D stated that “These findings support previous research that calcium supplements can interfere with levothyroxine absorption.

The study

  • This study considered of 10 adults who had an average age of 33.7 years between them.
  • The split was 6 men and 4 women with no known thyroid disease and normal thyroid function before testing began.
  • No known allergies to either Levothyroxine or cow’s milk.

The study consisted of 2 different visits, a month apart from each other. Participants had to fast overnight before each one. Regular blood tests were taken through to measure T4 levels.

  • On the first visit, each candidate had to take 1000micrograms of oral Levothyroxine with nothing else.
  • On the second visit, they each took the same amount of Levothyroxine, plus 12oz of 2% cow’s milk.

Due to the regular blood tests being taken, investigators could measure Levothyroxine absorption through the amount of total T4 in the blood.

Results revealed that those who consumed both medicine and milk in conjunction had a lower T4 level.

The brand manufacturer of levothyroxine has recommended that the medicine should preferably be taken on an empty stomach, 30-60 minutes prior to eating or taking any other medication or supplements.

Given the study’s findings, a correlation can be seen that cow’s milk could have an interference with those who manage with thyroid replacement therapy.

Study link:

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