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Can low carb intake interfere with Synthroid absorption?

Lately I reduced the carb and noticed an increase in my TSH labs from 2 to 10. Just wondering if low carb diet could be the problem.
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Avatar universal
I can only address areas of familiarity on my part.   What stands out to me is the doctor trying to fine-tune your thyroid by having you on 100 mcg of Synthroid 5 days a week and 88 the other two days.  Yet the doctor is ignoring the fact that your FT4 is only at 30 % of its range, and your FT3 is at rock bottom of the range.  FT3 largely regulates metabolism and is used by all the tissues of your body.  FT4 is important as a source of FT3, by conversion.  

When taking T4 med it is quite common to have inadequate conversion of T4 to T3  For good conversion you need for ferritin level (storage form of iron), to be at least 100.   Your med dosage is not even enough to get your FT4  to mid-range, much less enough to get FT3 to a good level.  I expect that the doctor is adjusting med dosage based on TSH levels, which doesn't work:  the most important thing is how you feel.  From the following list of symptoms typical of hypothyroidism, which ones do you have?

Increased sensitivity to cold
Constipation (need to use laxatives or fiber)
Dry skin  (have to use skin creme)
Weight gain
Puffy face
Muscle weakness
Elevated blood cholesterol level
Muscle aches, tenderness and stiffness
Pain, stiffness or swelling in your joints
Heavier than normal or irregular menstrual periods
Thinning hair
Slowed heart rate
Impaired memory

A good thyroid doctor will adjust FT4 and FT3 levels as needed to relieve hypo symptoms, without going so far as to cause hyper symptoms.   I think you need to add a source of T3 to your med dosage and increase it as needed to feel well.   Since you are taking thyroid med, I am not sure why you are taking iodine.   Also,  if your cortisol test is correct in showing high cortisol, that would further indicate the need for your thyroid levels to be higher.  Since cortisol offsets thyroid effects they need to be in relative balance.  

Personally I would stop worrying about all the other issues that seem to be on your mind, and get your thyroid levels adequate.  I think you will then be surprised at the effect on how you feel.  

If you want to confirm what I say, please read a paper I co-authored.  Here is a link.

Helpful - 1
Thank you! So you think is better to add to 100 mg Syntroid t3 only or increase the dose to 112 mg and then see how I feel? I feel a little tired some constipation and some depression! That’s all I can see from the hypothyroid symptoms list!
Based on you FT4 it seems that going to 100 every day would be adequate for that.  To get your FT3 level adequate you need to add a source of T3, like Cytomel or generic.   And increase dose as needed to relieve symptoms and you feel well.  That is the objective.  
Avatar universal
Low carb diet can affect thyroid levels.  Did you also test for the actual thyroid levels along with TSH,  If so please post those results and their reference ranges shown on the lab report.    The thyroid levels will be more indicative of your status than TSH.  Even though doctors like to believe that TSH is a very sensitive indicator of thyroid status,  it does not correlate well with either thyroid hormone Free T4 or Free T3.  
Helpful - 1
Month before taking the blood test I was taking 100 mg Synthroid 5 days a week and 88 mg Synthroid 2 days a week. I am supplementing with Vit D iron and B12 so they should be in a good range based on the previous tests. I am also taking iodine 4 times a week 3 mg along with 100mcg selenium. iodine is around 74 mcg/L with a range (52-109).
AST is 20 range (10-30)
ALT is 17 range (6-29)
Free T4 1.1 ng/dL range (0.8-1.8)
Reverse T3 ng/dL range (8-25)
Free T3 2.3 pg/dL range (2.3-4.2)
estradiol 17 luteal phase range (56-214)
progesterone 0.6 luteal phase range (2.6-21)
cortisol am 25.7 range (4-22) high.
Currently I am taking 100mg Synthroid every day and 5 mg of T3 but I might increase to 10 because I have symptoms of bad adrenals and hypothyroid.
My nutritionist also suggested to take B5 and adrenals for few months to see if anything changes. I am also taking digestive enzymes with every meal( 3 meals a day). I started to incorporate more carbs but before I was on a very low carb diet, less then 50 grams a day. So is it possible that low carb diet cause my TSH to raise since in the past 100 mg of synthroid every day would show good thyroid labs.
Also seems that i have very low female hormones and the ratio seems to show estrogen dominance. It seems that adrenals-ovaries-thyroid liver-gut are related and I dont know how to fix all of them at the same time. its very hard to balance them.
Your thoughts will be very much appreciated since you have experience seeing so many labs.
my weight is stable 112 lb(5.3 height), ( i am ok with this weight) but I do feel bloated sometimes and take magnesium every night.
Reverse T 3 is 17
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