NDT and sublingual B12.

[michellebelfast]

Hello everybody! Just a quick question - I would really appreciate an answer. Does taking sublingual methyl B12 plus recommended co factors affect the amount of NDT I take. I am currently on 4 grains. Thanks!

[Pastille]

Hi michellebelfast , any supplements that you take may interfere with absorption which is why it is recommended to leave a couple of hours between them, 4 hours for Iron and 6 for Calcium. Other than that the only affect they have is a good one as when our levels are optimal we absorb the medication better. Hope that helps a bit

[Heloise]

Hi Michelle, that is a fairly high dose of thyroid hormone. Is your TSH totally suppressed? This has more impact on your NDT than B12. Cortisol and iron have to be in the right level for good conversion of FT4.

Insulin resistance/diabetes/metabolic syndrome/obesity

From the National Academy of Hypothyroidism:

As with leptin resistance, it has been shown in numerous studies that insulin resistance, diabetes, or metabolic syndrome have associated significant reduction in T4 to T3 conversion, an intracellular deficiency of T3, and an increased conversion of T4 to reverse T3, further reducing intracellular T3 levels (91,100,92,94,147,184-193,235). Additionally, the elevated insulin will increase D2 activity and suppress TSH levels, further decreasing thyroid levels and making it inappropriate to use the TSH as a reliable marker for tissue thyroid levels in the presence of elevated insulin levels as occurs with obesity, insulin resistance, or type II diabetes (91-99,233).

Pittman CS et al. found that normal individuals had a 77% conversion of T4 to T3, while diabetic individuals had a 45% conversion of T4 to T3 and increased T4 to reverse T3. Improvement in glucose levels only slightly increased T4 to T3 conversion to 46% (93).

Islam S et al. investigated the T4 to T3 conversion in 50 diabetic patients compared to 50 non-diabetic controls. There was no difference in TSH and free T4 levels, but the diabetic individuals had significantly decrease free T3 levels (p = 0.0001) that averaged 46% less than controls. The FT3/FT4 ratio was 50% less in diabetic patients versus controls. The TSH failed to elevate despite the fact that serum T3 was approximately half of normal (92). Saunders J, et al. also found that diabetics had approximately a 50% reduction in T3 levels and significantly increased reverse T3 levels and decreased T3/reverse T3 ratios (94).

In the International Journal of Obesity, Krotkiewski, et al. published the results of their investigation of the impact of supplemental T3 on cardiovascular risk in obese patients to partially reverse the reduced T4 to T3 conversion seen with obesity (53). Seventy obese patients with “normal” standard thyroid function tests were treated with 20 mcg of straight T3 for six weeks. While the dose was not high enough to completely reverse the reduced T4 to T3 conversion seen with obesity, there was a significant reduction in a number of cardiovascular risk factors, including cholesterol and markers for insulin resistance. There were no side-effects in any of the patients. The authors conclude, “T3 may be considered to ameliorate some of the risk factors associated with abdominal obesity, particularly in some subgroups of obese women with a relative resistance to thyroid hormones possibly dependent on decreased peripheral deiodination of thyroxine (T4) (53).”

Thus, replacement with timed-released T3 preparations to normalize the reduced intracellular T3 levels is appropriate in such patients despite so-called “normal” levels while, on the contrary, T4-only preparations do not address the physiologic abnormalities of such patients and should be considered inappropriate replacement for obese patients or those with insulin resistance, leptin resistance, or diabetes, as they do not address the physiologic abnormalities in this group.

[colorado0721 in reply to Heloise]

Very helpful post!

[Heloise in reply to colorado0721]

I'm glad. The site is rather technical but much of it is understandable.

You can read more here if you haven't looked it up already. nahypothyroidism.org/deiodi...

[Clutter]

MichelleBelfast,

Supplementing shouldn't affect absorption of NDT if you take it 2 hours away from most supplements and medication, and 4 hours away from calcium, iron, vitamin D supplements, and oestrogen.