Iodine

Toxicity (UL)

1,100 micrograms

Examples of goitrogens

Cassava, raw veggies in excess (cabbage, broccoli, brussel sprouts) and lithium

Cretinism is either...

- Neurological (irreversible) - Hypothyroid (reversible)

Iodine is a halogen so...

- its a nonmetal - typically found as Iodide (I-)

Assessing iodine techniques:

-Urinary iodine excretion -Thyroid size -Serum TSH concentrations

5-30% of iodine deficiency is

brain damage

Iodide deficiency effects depend on age of exposure. So, the embryo/fetus has profound effects. Infants and children:

failure to grow normally and develop intellectually

Very efficient absorption results in..

few low fecal iodide content

Thyroid hormone has its receptors in the nucleus so it is largely influenced by

gene expression

Thyroid hormone promotes activites associated with ______ which increases metabolism and heat production

glucose breakdown

Deficiency of iodine results in

goiter

When iodine deficiency occurs in children and adults, the thyroid gland grows and becomes enlarged, producing ___ a classic sign of iodine deficiency

goiter

An adult contains roughly ______ milligrams of iodide

15-20

RDA

150 micrograms (1/4 teaspoon of salt is 70 micrograms)

Cretinism

3rd trimester, stunted growth and mental development. Large heads, deaf (mostly in developing countries)

The thyroid gland contains roughly _____ of body iodide

75-80%

Overall absorption is greater than

90%

What is needed in iodine

Active transport

Compounds that inhibit iodine uptake by the thyroid gland are found in which of the following foods?

Cruciferous vegetables (cabbage like) raw

Iodine deficiency and iodine deficiency disorders (IDD)

Goiter, cretinism (neurological and hypothyroid)

Which compounds inhibit iodine uptake by the thyroid gland?

Goitrogens

#1 consequence of iodine deficiency

Increased risk of fetal and infant mortality

What may happen when theres goitrogens?

Interferes with thyroid hormone production May impair uptake of ioide into thyroid gland May affect hormone production or release

Thyroglobin

STORAGE FORM OF IODINE in which idioine in the thyroid gland is incorporated into this protein

Goitrogens

Substances that interfere with iodine metabolism that leads to a goiter

Almost all of the tyroxine (T4) in the circulation may become converted to ____ after entering peripheral tissue

T3

So which is more metabolically active?

T3

THriodothyronine is

T3

What are referred to as the thyroid hormone?

T3 and T4

Thyroxine is

T4

Roughly 90% of thyroid hormone released daily is:

T4 - this is PREDOMINATING IN THE BLOOD

T3 and T4 bund to

TBP

Thyroid gland:

TSH stimulates the thyroid gland to take up iodine and produce thyroid hormones (T3 and T4)

Iodine functions and mechanisms of action:

Thyroid hormone synthesis Transport of thyroid hormones in the blood

Hypothyroid can occur...

later in pregnancy and symptoms are sleepy, slow development

Today, thyroid hormone is prescribed to treat hypothroidism,

a condition in which the thyroid gland fails to produce adequate thyroid hormone

30-70% of iodine deficiency comes is

loss energy due to hypothyroidism

Brain:

low in blood iodine concentration

Iodide deficiency has been eradicated for most part from many regions so, they did what?

added iodine to salt

Impaired selenium status...

affect thyroid hormone metabolism

If sadie wanted to avoid cruciferous veggies, she would avoid

cabbage, cauliflower, and brussel sprouts

_____ are more suspectible to iodine deficiency

children

When a baby experiences iodine deficiency in utero, ___ may result

cretinism

Neurological cretinism is due to a iodine deficiency in..

early pregnany that damages brain and nervous system. This can be mild to severee

Dans grandfather has a goiter. The goiter could be the result of

either a iodine deficiency or iodine toxicity!!!

In the muscle, iodine...

enhances contraction

In the adipose tissue, iodine...

enhances lipolysis

Thyroid hormone affects virtually...

every cell in the body (with the exception of the adult brain, testes, spleen, uterus and thyroid gland itself)

Iodine deficiency results in all of the following except

excessive growth in stature

Iron and vitamin A deficiencies may..

magnify effects

goiter

hypertrophy of the thyroid gland

Approximately 90% of iodine is excreted..

in the urine within 1 or 2 days

in the cardiovascular system, iodine...

increases heart rate

Pituitary gland:

increases release of thyroid stimulating hormone (TSH)

Low bloow levels of ___ stimulates the pituiary gland to increase release of TSH

iodine

Which trace mineral is an essential component of the hormones produced by the thyroid gland?

iodine

The best source of iodine in the american diet is

iodized salt

Other consequences of iodine deficiency

irreversible mental and neurological retardation, hypothroidism, goiter

Excessive iodide is primarily excreted by the

kidneys

Iodine excretion is in:

mostly urine, also feces (low) and sweat

The absorptioj of iodine occurs efficiently along the length of the intestinal tract, including the stomach. This results in..

nearly complete absorption of iodide, like sodium, potassium and chloride

Thyroid hormone output thus increases and exerts...

negative feedback on the release of TRH

HOWEVER, T3 is 5 to 10 times more ___ than T4

potent (stronger)

Now, there is a worry that the US is using too much iodized salt in..

preparation, manufacturing and seasoning

Iodine deficiency is the greatest single cause of..

preventable brain damage and mental retardation in the world today (AFRICA)

At least 60 micrograms of iodide must be taken up by the thyroid gland daily in order to..

produce adequate thyroid hormone

in the bone, iodine...

promotes anabolism (growth and development)

Dairy foods are a fair source but it...

reflects what the cows feed or the soil of its grazing region was

Other sources:

salt, haddock, cottage cheese, shrimp, egg, cheddar cheese, ground beef

Main 2 sources:

seafood, iodized salt. 1/4 teaspoon provides 70 micrograms of iodide

Treatment of the goiter can..

shrink it but not necessarily correct any of the developmental problems in children

Food content variable based on..

soil concentration and water source

In metabolism, iodine..

stimulates metabolic rate and cellular oxygen consumption in metabolically active tissue

In the gastrointesinal tract, iodine...

stimulates nutrient digestion and absorption

The hypothalamus releases the peptide thyrotropin-releasing hormone which...

stimulates the pituiary to produce thyroid stimulating hormone or thyrotropin

Community assessment

testing people in areas suspected of deficiency, physical exams, hormone levels, urine samples

Iodide appears to dissolved freely into

the blood

Toxicity is possible and may cause problems with the..

thyroid gland

For the most part, iodide is concentrated in the

thyroid glands as well as the salivary gland and gastric glands

TSH circulates to the thyroid gland which initiates production of...

thyroid hormone which then enters the blood and circulates to peripheral tissue

Iodine is an essential component of the..

thyroid hormones

Iodine uptake by the thyroid is regulated by

thyroid-stimulating hormone

Transport of thyroid hormones in the blood include:

thyroxine-binding globulin, albumin and transthyretin

Approximately 80% of thyroid hormone binds to

thyroxine-binding protein (TBP)

Methods of checking deficiency:

urine excretion, checking for the size of the thyroid gland, checking TSH level and serum thyroglobulin