Lecture 18

Question 1

What trace elements are low in NZ soil?

Answer 1

• Fluoride
• Selenium
• Iodine

Question 2

What are the strategies for increasing dietary intake in NZ?

Answer 2

1. Fortification - adding to staple foods e.g. bread
2. Supplementation - good for target groups e.g. pregnant women, as people aren’t very compliant
3. Dietary Diversification - works for individuals with simple diets e.g. African. This technique DOES NOT WORK IN NZ

Question 3

What are the functions of Iodine?

Answer 3

• Key part of thyroid hormones (T4 and T3)
• Maintains metabolic rate
• Needed for growth and development

Question 4

Why does a goitre form?

Answer 4

-Enlarges to try capture more iodine as a consequence of low iodine levels

Question 5

What are the dietary sources of Iodine?

Answer 5

1. Rich sources
   - >fish/seafood
   - >iodised salt
2. Moderate source
   - >eggs
   - >milk/milk products
   - >fortified bread
3. Poor Sources
   - >fruit and vege

Question 6

Describe the absorption of Iodine

Answer 6

100% absorbed, not regulated

Question 7

What % of iodine is excreted in the urine?

Answer 7

90%

Question 8

Are there any iodine stores in the body?

Answer 8

• No stores

- Thyroid hormones can be stored for up to 3 months

Question 9

How is iodine status assessed?

Answer 9

• Median urinary iodine concentration
• Thyroid volume : goitre rate (<5%)
• Thyroid hormones T3/4/g

Question 10

Describe the deficiency history in NZ

Answer 10

1911-30’s = mild-moderate IDD

• > low urinary iodine
• > up to 30% of children with goitre
• > no reports of cretinism

1940’s = iodised salt

1950’s = goitres become infrequent

1960’s = (at this point levels were sufficient) introduction of iodophors

1990’s = deficiency

Question 11

What are the reasons for re-emergence of deficiency?

Answer 11

1. Fast food intake increasing which doesn’t use iodised salt
2. Health recommendation to decrease salt
3. Dairy industry stopped using iodophors
4. Rock and sea salt used (not iodised salt)

Question 12

What improvement methods were implemented to increase iodine levels?

Answer 12

1. Supplementation = pregnant and lactating women recommended a tablet
2. Fortification = mandatory use of iodised salt for bread making

Question 13

What symptoms are seem at mild deficiency?

Answer 13

People with a goitre

Question 14

What symptoms are seem between mils and moderate deficiency?

Answer 14

Impaired mental and motor abilities

Question 15

What symptoms are seem at moderate deficiency?

Answer 15

Hypothyroidism

Question 16

What symptoms are seem at severe deficiency?

Answer 16

Cretinism

->when an iodine deficient mother has a child