Relationship between iodine and cancer

The thyroid, hormones, iodine and cancer

relationship between iodine and cancer

It remains to be resolved whether the perceived breast cancer–thyroid disease relationship is thyroid or iodine related or, in the case of thyroid autoantibodies. I have put together some resources for the thyroid, hormones, iodine, etc., other than the This is a link to a website that contains an overview of the book: The. Total iodine content of the body is estimated at 25 mg to 50 mg, with . The link between gastric cancers and areas of endemic goiter dates back to ,42 and .

Such an association is not surprising as both diseases are female predominant with a similar postmenopausal peak incidence. The significance of the presence of thyroid autoantibodies, particularly thyroid peroxidase antibodies, in serum from patients with breast cancer is unknown, but it has been suggested that antibody positivity is associated with better prognosis.

One area in which thyroid and breast functions overlap is in the uptake and utilization of dietary iodide.

Iodine and Cancer

Experimental findings showing the ability of iodine or iodine-rich seaweed to inhibit breast tumour development is supported by the relatively low rate of breast cancer in Japanese women who consume a diet containing iodine-rich seaweed. However, there is as yet no direct evidence that iodine, iodinated compounds, or a combination of iodine and selenium is the antimammary carcinogenic element in the Japanese diet.

  • What Does an Iodine Deficiency Have to Do with Cancer? (video)
  • The thyroid, iodine and breast cancer
  • Urinary Iodine Concentrations in Cancer Patients

It remains to be resolved whether the perceived breast cancer—thyroid disease relationship is thyroid or iodine related or, in the case of thyroid autoantibodies, is the consequence of an immune response to the carcinoma. Is this response breast specific and does it relate to iodine status? These and many other questions await resolution before a definitive role in the natural history of breast carcinoma can be assigned to the thyroid.

This finding is in agreement with previous studies [ 23 ] that showed both increased goiter rates and increased prevalence of thyroid enlargement by ultrasound in patients with breast cancer [ 4 ]. This association represents yet another page in the continuing saga of the perceived coincidence between breast cancer and diseases of the thyroid gland. The fact that both breast cancer and thyroid disease predominantly affect females and that both have a postmenopausal peak incidence has inevitably resulted in a search for an association between the two diseases [ 56 ].

Although many studies have shown such an association, evidence of specific causal linkage between thyroid breast cancer and thyroid disease continues to be elusive. One of the earliest reports on the association of breast cancer with thyroid disease was that from Beatson [ 7 ] inwho used oopherectomy and thyroid extract to treat breast cancer.

Since that report there have been many studies showing an association of breast cancer with hyperthyroidism, hypothyroidism, thyroxine replacement therapy and thyroiditis [ 56 ].

Equally, other reports showed no significant association. Where an association between thyroid disease and breast cancer was shown to exist, hypothyroidism was the most frequently observed finding.

In fact, many reports considered hyperthyroidism to be protective against breast cancer because progression of such cancers was more frequently observed when the hyperthyroidism was treated [ 5 ]. The increased frequency of thyroid autoantibodies, TPO antibodies and thyroglobulin antibodies described by Turken and coworkers [ 1 ] in breast cancer patients as compared with control individuals supports earlier findings [ 8 - 11 ].

Such differences were not observed for other autoimmune antibodies [ 9 ]. The use of specific immunoassays for TPO antibodies and thyroglobulin antibodies [ 12 ] revealed an increased prevalence of TPO antibodies in breast cancer.

Although the presence of circulating TPO antibodies in asymptomatic individuals has been implicated as conferring an increased risk for future hypothyroidism [ 13 ], there is no agreement on the significance of its association with breast cancer [ 14 ]. However, no significant association between breast cancer and Hashimoto's thyroiditis was reported in a study from the Mayo Clinic in the USA [ 15 ].

Thus, like other reported associations, the relationship between AITD, iodine intake and breast cancer is far from clear. Equally, there is little agreement on the significance of any published association between a range of thyroid disorders and breast cancer [ 56 ]. The possibility that hypothyroidism might in itself have been beneficial in terms of outcome of breast cancer has been suggested [ 16 ].

Recent reports from our laboratory [ 11 ] have shown that the presence of TPO antibodies is associated with a significant improvement in both disease-free and overall outcome in breast cancer patients, and that the magnitude of this prognostic effect was of a similar order of magnitude to well established prognostic indices for breast cancer such as axillary nodal status or tumour size. Thus, we have the anomalous situation in which the presence of TPO antibodies, while being associated with breast cancer, also appears to confer prognostic benefits.

A recent review that contained a meta-analysis of published work on breast—thyroid associations [ 14 ] found no significant association between the two disorders and attributed any positive findings of such an association to 'selection or institutional referral bias'. This negative finding was immediately followed by communications [ 117 ] reaffirming the association of breast cancer with hypothyroidism and AITD.

relationship between iodine and cancer

It is therefore apparent that the argument about breast—thyroid associations is far from resolved. Thyroid antibody related hypothyroidism has been suggested as being associated with a favourable tumour response to such therapies. In a recent report [ 19 ] it was shown in metastatic renal cell carcinoma that the presence of a positive thyroid antibody titre, either pre-existing or cytokine induced, was a highly significant independent prognostic factor.

Urinary Iodine Concentrations in Cancer Patients

In the case of thyroid autoantibodies being associated with better disease outcome in breast cancer, renal carcinoma or melanoma, it is possible that the immune response to thyroid and tumour tissue might be similarly regulated in that it might be directed against both tumour and thyroid antigens. Another possibility is that both tumour and thyroid share the same antigens because expression of the sodium—iodide symporter has been demonstrated in both thyroid and breast tissues [ 20 - 22 ].

Breast cancer is linked to high thyroxine levels in women. Goiter incidence has epidemiological links to breast cancer incidence.

The thyroid produces several hormones, notably thyroxine and trilodothyronine, which control metabolism, growth and rate of energy consumption in all the cells of your body.


Another hormone, calcitonin, controls calcium metabolism in the body. The thyroid is under the control of the pituitary gland, which is regulated by the hypothalamus. Higher concentrations of iodine have been found in the following tissues: Salivary glands, stomach lining, tear ducts, eye, brain, spinal fluid and skin. Most interestingly, the transporters are well concentrated in the placenta, and lactating mammary gland both to feed baby and in the ovary, uterus, pancreas and prostate.

Deficiency symptoms These include fatigue, headaches, muscle cramp, lowered mental capacity, brain fog, dry mouth, dry skin, brittle nails, loss of eyebrow hair, muscle pain, nodules, cysts, fibroids and fibromyalgia. Iodine in the body Your thyroid reduces iodine into iodide, which is used to build the hormone thyroglobulin. Sources of iodine Natural sources include sea vegetables like kelp, arame, wakame, hiziki and kombuoysters, prawns, crab, mussels, sea fish, organic strawberries, cranberries, eggs, cheese and potatoes especially in the skin.

It is best to steam your shellfish to avoid parasitic infections.

The thyroid, iodine and breast cancer

Kelp provides by far the highest source — one serving can provide up to four times the RDA. So how much is enough? The RDA is a very lowly figure — measured in micrograms. A number of health experts believe it to be totally inadequate.

But there are also serious risks if you take too much.

relationship between iodine and cancer

The RDA is micrograms for adults, increasing to for pregnant women and for lactating women. To put this in context, research from Japan suggests their average dietary intake is About times higher!

relationship between iodine and cancer

A number of Western health experts believe that level should be recommended in the West as we have far higher cancer rates than the Japanese. The FDA has actually recommended a daily dose of mg in case of a Radiation emergency such as a nuclear event. Clearly, there is a huge variation in daily levels recommended. The World Health Organisation estimates that at least 15 per cent of women in the Western World are deficient in iodine.

Many experts believe that is a gross underestimate. A quality kelp from a quality supplier is crucial.

This has the two types of iodine that the body uses.

relationship between iodine and cancer

Often used as an antiseptic and disinfectant, it is a source of free iodine and was used with people around Chernobyl after the disaster.

It is made in different potencies — e. Nascent Iodine is the most bioavailable biochemically to the body. One, Ioderol, from Optimox is in tablet form, and is recommended to be taken with magnesium and vitamin C. Nascent Iodine is also available in liquid form. Iodine depletion This is an important issue. The following may deplete your iodine levels: Most common sources are pesticides and fumigants, plastic packaging, drugs, and soft drinks and baked products. Bromides are now added to flour; whereas iodine was added to bread prior to the s.

Both displace iodine in the body — so water supplies can deplete iodine levels as can a variety of in-home compounds from plastic packaging to toothpaste, mouthwash and flame retardants and perchlorates.

Iodine is a trace mineral. Soil depletion reduces its already low volumes. Declining consumption of iodine-rich foods like oysters, prawns, sea fish, eggs and iodised salt. Antioxidant ability To put iodine in context as an antioxidant, iodine is known to increase blood antioxidant capacity and to affect glutathione levels inside the cell.

It is known to counteract free-radicals, and, in one study, was found to be 10 times more potent than vitamin C. Goitre Goiter is a swelling of the neck due to a thyroid gland not functioning properly. About 9 in 10 cases worldwide are due to iodine deficiency.

However, Goitre can be associated with hyperthyroidism, or hypothyroidism. Goitre may also result from selenium deficiency or even cyanide poisoning, as seen in some tropical countries where cyanide-rich cassava root is a staple food.

Goitre is more common among women.