Iodine 1

Question 1

Why is NZ low in trace elements and what elements are they low in?

Answer 1

The content of some trace elements in the soil of NZ is low, due to glaciation, lots of flooding and type of soil
NZ soils are low in fluoride, selenium and iodine, as we tend to eat food grown in soil, low levels in diet may affect health

Question 2

What is iodine?

Answer 2

Iodine is the integral part of thyroid hormones which are needed to maintain the BMR and needed for growth and development
Negative feedback mechanism - if you don’t get enough T4 thyroid hormone, the brain produces more TSH causing thyroid gland to produce more thyroid hormone and increases in size

Question 3

Where can we get iodine from in our diet?

Answer 3

Rich sources of iodine include fish, seafood and iodised salt
Moderate sources include eggs, milk and milk products, fortified bread
Poor sources include fruit and vegetables

Question 4

How is iodine metabolised?

Answer 4

Almost all iodine is absorbed - not regulated
~90% of dietary iodine is excreted in urine
No iodine stores however thyroid hormone stored for ~ 3 months in thyroid gland
Measure urinary excretion of iodine to find iodine intake
If concentration is over 100 then iodine status is good
<5% of population should have a goitre (can be measured by ultra sound)

Question 5

What are some iodine deficiency disorders?

Answer 5

Mild iodine deficiency: common in NZ, have a goitre which generally means they can make enough thyroid hormone
Moderate IDD: more people have a goitre and thyroid hormones start to affect BMR, mental and motor abilities
Severe IDD: really low thyroid hormone, hypothyroidism (low thyroid levels)
If a women is iodine deficient and is pregnant, the child could have cretinism - short, squint, deaf or mute and IQ 30

Question 6

Why did iodine deficiency re-emerge in NZ?

Answer 6

1. People started using Himalayan salt which doesn’t have any iodine
2. Began to use less salt than what was recommended
3. Iodine containing disinfectants in dairy industry was replaced with detergent ones, iodine in dairy content dropped
4. We are eating more foods prepared outside home/eating more processed food - most food is prepared with non iodised salt