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Iodine.

Article Excerpt
Continuing education and the APD program

This quiz is an ideal activity for APD members to include in your CPD log, where it relates to personal learning goals. Record the time taken, to the nearest hour, to complete the quiz and any associated research.

INTRODUCTION

Iodine is an essential micronutrient that typically exists in its ionic form, iodide. The human body contains only about 15-20 mg of iodine of which about 70-80% is in the thyroid gland. (1)

The iodine content of foods is remarkably variable, even within the same food item, and it is difficult to obtain an accurate estimate of iodine status from dietary intake as data are limited on the iodine content in foods. This wide variability in food content can be explained by the iodine cycle. (2) Iodide in soil and seawater is oxidised by sunlight to iodine, which evaporates; whereas some iodide is returned to the soil by rain, more on balance is leached out of soil by glaciation, high rainfall and flooding, increasing the content of river waters, and ultimately reaching the sea. (2) Because iodide present in both animals and plants varies with the regional content of the soils and water on which they grew, the content in foods depends on the age, geography and degree of leaching of the local landscape and soil. (2) One important consequence of the iodine cycle is its impact on the nutritional status of iodine, which is determined by the geographical distribution of iodine and does not necessarily respond to changes in socioeconomic status or food choices.

The following quiz is designed to enhance your understanding of iodine from a nutritional science perspective. It will test your knowledge of basic concepts including the major food sources and nutrient interactions, requirements, metabolism, deficiency and possible toxicity.

1. Which of the following food groups provide a source of iodine?

a. Vegetables

b. Dairy, eggs and meats

c. Seafood

d. All of the above

2. What is the recommended dietary intake for iodine?

a. 150 [micro]g

b. 70 [micro]g

c. 45 [micro]g

d. 35 [micro]g

3. What is the upper limit of intake for iodine?

a. 550 [micro]g/day

b. 1100 [micro]g/day

c. 1700 [micro]g/day

d. There is no reported toxicity and no upper limit of intake

4. What is the main function of iodine?

a. Cofactor for enzymes involved in the production of ATP

b. Cofactor for enzymes involved in catabolism of purines and pyridines

c. As a component of thyroid hormones

d. All of the above

5. Selenium deficiency has been reported to exacerbate the effects of coexisting iodine deficiency through which of the following:

a. Iodothyronine deiodinase activity

b. Glutathione peroxidase activity

c....

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