Iodine, a global deficiency

Iodine, Over a third of the global population is exposed to iodine deficiency, especially in the mountains.

Most common global preventable cause of mental impairment

Iodine deficiency

Serious iodine deficiency during pregnancy can result in stillbirth, spontaneous abortion and congenital abnormalities such as cretinism

Role of Iodine in Metabolism

Urinary Iodine Concentration

In healthy, iodine-replete adults more than 90% of dietary iodine is absorbed from the small intestine and more than 90% is excreted within 24-48 hours

Functions

Control of metabolic rate, energy levels, weight management, brain function, cardiovascular health, foetal and child development, reduced still births, infection protection in children, breast, ovary, uterus protection, prostate.

Many organs can also actively accumulate iodine: salivary glands, stomach, lactating mammary gland, ovary, prostate, pancreas.

Recommended dietary intake,150 μg/day

The correlation between iodine and metabolism: a review

Changes in Dietary Iodine Explains Increasing Incidence of Breast Cancer with Distant Involvement in Young Women

Fibrocystic breast disease

Iodine deficiency is associated with fibrocystic breast disease

Fibrocystic breast disease can be effectively treated with iodine

Fibrocystic breast disease affects at least 50% of women of child-bearing age,

and is associated with an increased risk of developing breast cancer.

Breast cancer

Increasing breast cancer in younger women since mid-1970s

Often presenting late

Iodine deficiency has been proposed to play a causative role in the development of breast cancer

Dietary iodine has also been previously proposed to play a protective role in breast cancer

Japanese women, have exceptionally low incidence of breast cancer

Emigration of Japanese women, adopting a western diet, associated with higher breast cancer rates.

Iodine is taken up by the sodium/iodide symporter in the breast

This is important in promoting the development of normal versus neoplastic breast tissue development

Reduce breast cancer

Vit D and K2, phytonutrients, cruciferous veg, cauliflower, cabbage, kale, garden cress, bok choy, broccoli, Brussels sprouts, omega 3

Mechanism of action of iodine's anticancer effect

Antioxidant, iodide has been found to be highly efficient in scavenging reactive oxygen species

Iodine also has well-known anti-inflammatory and immunomodulatory effects

Iodine promotes differential apoptosis

Iodine promotes of P53 tumour suppressor gene activity

Iodine plays a role in the development and maintenance of healthy breast tissue

Women with goitre have three times more breast cancer

Iodine deficiency results in “hyperresponsiveness” to oestrogen, resulting in increased cell proliferation, abnormal changes within nuclei,

Iodine is necessary for breast remodelling during lactation, and pregnancy

Young women and pregnant women, have lower urinary iodine levels than men of similar age.

Women of childbearing age exhibited the lowest urinary iodine levels of any age group.

Atypia is seen more in iodine deficiency in human and animal models

Temporal Changes in Body Iodine

There has been a drop in urinary iodine in young women as well as in the general population, since the 1970s

Nutrition Examination Surveys,

A significant decrease in urinary iodine levels in the overall population during the period 1988-1994 as compared to the period 1971-1974 (P less than 0.0001).

Percentage of people with iodine deficiency, (below 50 μg/L)

(WHO recommend 100- 199 - 249 μg/liter urinary iodine, less than 100 μg/L indicates that the population's iodine intake is insufficient.)

1971-1974

2.6% during the period

1988-1994

14.5% of the population iodine deficient by WHO criteria,

representing a 5.6-fold increase since early 1970s

Females showed a higher frequency of iodine deficiency than males (15.1% versus 8.1%).

Lower Urinary iodine levels in black relative to white women may also explain the greater increase in frequency of distant breast cancer in black women

2005-2008

Pregnant women had median urinary iodine levels of 125 μg/liter,

and 56.9% had levels less than the WHO recommended 150-249 μg/liter

Lancet, 2013

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