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The Absorption of Thyroid Medications

thyroid medication

For some lactose intolerant people, even tiny amounts of lactose that are found in thyroid medications can be an issue, resulting in impaired absorption of thyroid medications. Yes, thyroid medications could be sabotaging their own absorption if they contain even teeny amounts of lactose.So if you are someone that can’t get his/her TSH into your sweet spot (TSH should be between 0.5-2 mU/L for most people to feel best) despite taking escalating doses of thyroid medications, consider lactose intolerance and the possibility that the lactose in your diet or even in your thyroid medication may be inhibiting its absorption.

Lactose Containing Thyroid Medications
• Synthroid
• Euthyrox
• WP Thyroid
• Nature-Throid
• Most generic brands of levothyroxine
• Some compounded medications- check with your pharmacist

Lactose Free Thyroid Medications
• Tirosint
• Armour Thyroid
• Cytomel***may be cross-contaminated with gluten***
• Levoxyl
• Some compounded medications- check with your pharmacist

Medication Tips

All of the T4 containing medications, Tirosint has the fewest fillers that may impair absorption, and this medication was specifically designed for this purpose. I’ve had many people on my Facebook page comment on how they felt much better on Tirosint compared to levothyroxine. Of course, many people do not feel good on T4 only medication and that is beyond the scope of this post (this post is getting a wee bit long), but you can read more about that at which thyroid medication is best, if you are interested. Of all of the T4/T3 combination medications, WP Thyroid has the fewest fillers that can impair absorption. Armour thyroid does not contain lactose but contains corn-derived ingredients that can be problematic in corn sensitive individuals.

Other Factors Contributing to Medication Absorption
A 2012 Polish study by Ruchala and colleagues reported that thyroid patients who need more than 2 mcg/kg/day of levothyroxine with an increased TSH should be suspected of an absorption disorder.This disorder could be caused by lactose intolerance, celiac disease, atrophic gastritis, H. pylori infection, inflammatory bowel disease, or parasite infection. Interestingly, in my experience, many of these are also potential root causes of autoimmune thyroid disease and addressing some of these has helped people get into remission. Read more in my article 6 Hashimoto’s Root Causes. You can be tested for lactose intolerance, celiac disease, atrophic gastritis or inflammatory bowel disease by most conventional doctors.For H. pylori and parasite infections, I only recommend working with these specific functional labs: BioHealth Lab, Diagnostic Solutions, and Genova. You would need to have a functional medicine doctor order those tests for your, or you can self-order them (scroll down for more info and resources). Please note, another study found that 54% of people with hypothyroidism had SIBO, and one of the symptoms of SIBO is lactose intolerance. While this study found that treating SIBO helped the many digestive symptoms experienced by the patients, treatment of SIBO didn’t increase the absorption of thyroid
medications.

I wonder if this is because the lactase enzymes do take a few months to regenerate if they do come back at all after treating SIBO, and the participants in the study were not placed on a lactose-restricted diet. It’s important to find out if you have SIBO because this can be an underlying root cause of Hashimoto’s, and treating the SIBO can not only help your sugar digestive enzymes to regenerate but can also result in remission from Hashimoto’s in some cases. SIBO is a hot new topic in the gut world, so some more progressive doctors may be willing to test you for it. Otherwise, you can self-order a 3- hour lactulose breath test. Low stomach acid can contribute to poor absorption as well. Some patients take their thyroid medications with a glass of water that includes squeezed lemon juice or a teaspoon of apple cider vinegar. I have had excellent results with using Betaine with Pepsin for low stomach acid.

Tips
Figure out your mcg/kg dose of thyroid medication. (Math refresher, take your current dosage of medication, then divide it by your weight in kilograms. To figure out your weight in kilograms, take your weight in pounds and divide it by 2.2.) Here’s a handy conversion chart if you take NDT medications to determine your approximate levothyroxine dose.

Key
If your TSH is around 1, and your dose is 1.31mcg/kg or less: your remaining triggers are likely to be outside of your gut. If your TSH is >1, and your dose is 1.31mcg or higher: suspect that you have lactose intolerance. If your dose is 2 mcg/kg or more: consider lactose intolerance + another gut disorder that could be inhibiting your medication absorption and potentially be the root cause of your condition.**Please note, the TSH is not the only important thyroid test, just the one that was used in research. For more info on the top thyroid tests, read THIS article.Consider testing for lactose intolerance or going lactose free. There’s a good possibility that if you have Hashimoto’s, you also have lactose intolerance. You can either put yourself on a lactosefree diet as a trial or have your doctor do a test for lactose intolerance. If you are someone that needs to see a test to take action (don’t worry, so was I), you can ask your doctor to order a hydrogen breath test for lactose intolerance or a lactose tolerance blood test for you. Consider having functional medicine tests for the following root causes: SIBO (Small Intestinal Bacterial Overgrowth Breath Test (BioHealth)); parasites and other gut infections (GI-MAP, GI Pathogen Screen 401H, GI Effects).


October 13, 2018
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