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Subtle Importance of Iodine when with thyroid hormones

Hidden Dangers of Achieving Recovery From Hypothyroidism Using Thyroid Hormone (Thyroxine = Synthroid/ Eltroxin) or Natural Dessicated Thyroid (NDT).

Subtle Importance of Iodine

For some people who experience symptoms of hypothyroidism, achieving a diagnosis of Hypothyroidism may be difficult. For those who are so diagnosed, the standard Thyroid Hormone for treatment tends to be Thyroxine, also known as T4 (Trade names: Synthroid/Eltroxin).

For others, Natural Desiccated Thyroid (NDT) tablets are necessary to achieve any improvement and for others T3 may be the treatment of choice, with or without NDT.

There are several difficulties in getting the right diagnosis and treatment in place.

However, the point of this text is not to dwell on such difficulties (e.g. difficulties such as: is adrenal function adequate for initiation of thyroid hormone replacement? is the Ferritin level right? have the levels of estradiol and progesterone been rectified? and so on). Rather, this paper picks up at the point where, thyroid hormone replacement therapy is in place and the patient has started to feel better.

So, does that mean everything is alright, now that thyroid hormone replacement is in place?

It has to be said that although many people do feel better, once diagnosed properly and treated appropriately with Natural Desiccated Thyroid, some do not return to their previous level of functioning. That is to say, they may not return to their healthy level of functioning before symptoms of hypothyroidism set in.

Apart from making an incomplete recovery, there are the prima facie puzzling reports of an association between Thyroid dysfunction and the hazards of breast cancer, other cancers and of diabetes which tend to attach to those who are taking thyroid hormone replacement .[1-4] Indeed the risk of breast cancer has been stated to be doubled in this situation.

The hazards of breast cancer are counter-intuitive. A person may say:

I feel so much better, now that my symptoms of hypothyroidism have been improved, why should I face the hazard of greater risk of breast cancer?

A possible answer is that Estrogen dominance, (a common predisposing factor in the development of hypothyroidism) appears to down-regulates the IODINE PUMP (Estrogen appears to produce this effect, experimentally). [5]

It seems that whatever thyroid hormone preparation used, which, in the situation of this Estrogen effect (i.e. Estrogen Dominance), serves to relieve symptoms of hypothyroidism, thyroid treatment is liable to conceal a continuing hazard of Iodine-deficiency-induced breast cancer. This is because: a) The cause of the original Iodine Pump down-regulation (Estrogen effect) has not been addressed and b) the thyroid hormone replacement used in therapy is liable to down regulate the Iodine pump further.

The following agents down regulate the Iodine Pump: Estrogen, T3, T4 Fluoride, Perchlorate, Interferon and Interleukin. [5, 6] This line of thought supports the mainstream view that, in thyroid hormone replacement, the TSH level should remain in the middle of the normal range. However that dosage does not always relieve symptoms.There’s a paradox and a therapeutic difficulty! What might/can be done to address that therapeutic difficulty? The question is: in the situation of Estrogen Dominance, treated by thyroid hormone replacement, does Iodine supplementation overcome this hazard? (Together with the “Companion Nutrients” as advocated by the “Iodine Research” group). [7]

The evidence suggests that the answer is “Yes, the implication being that most females who are being treated with thyroid hormone replacement should be on the “Iodine Protocol” to overcome the cancer hazard, caused by impaired Iodine absorption.

Unfortunately, the standard test for Iodine status in the human body (Urine Iodine level) tells us nothing about the state of Iodine absorption and therefore the true state of the bodys Iodine status. Saliva Iodine level (After Iodine loading, 50 mg) appears to be a more reliable test of the bodys true Iodine status. [8]It is also appears that exposure to Fluoride, by depressing Iodine uptake, potentiates the cancer risk here.

Unfortunately, when Thyroid Hormone Replacement is used in the treatment of symptoms of hypothyroidism, Iodine supplementation is not always used together with the “Companion Nutrients”. The evidence suggests that this supplementation should be in place.


  1. Turken O, Narin Y, Demirbas S, Onde ME, Sayan O, Kandemir EG, Yalaci M, Ozturk A: Breast cancer in association with thyroid disorders.Breast Cancer Res 2003, 5:R110-R113. PubMed Abstract | BioMed Central Full Text
  2. Eur Thyroid J. 2013 Jun;2(2):83-92. doi: 10.1159/000351249. Epub 2013 May 28.
  6. Daniel H.Y. Shen,1 Richard T. Kloos,2,3 Ernest L. Mazzaferri,2 and Sissy M. Jhiang1,2 Sodium Iodide Symporter in Health and Disease THYROID Volume 11, Number 5, 2001 Mary Ann Liebert, Inc


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Previous comments

I have found this very helpful. Once years ago – around 2003 – I was lucky enough to speak to Dr Peatfield and I asked him if it was OK to take a kelp tablet while taking NDT and he thought it could be a useful thing.

Pamela Comber,