iodine Flashcards
what type of element is iodine
trace element
what percentage of the total body iodide does the thyroid contain
70-80%
explain iodines importance in thyroid hormones
Integral to structure of thyroid hormones:
Thyroid glad makes thyroid hormones which important to our metabolism by controlling basal metabolic rate
Growth hormone is also a metabolic hormone which is obligatory to appropriate growth, and is Important for development of CNS – central nervous system. So why iodine important in babies
so If not enough idodine then not enough thiroid hormone production
iodine occurs in food in what form
as inorganic iodides (I-) or iodates (iodine and oxygen)(IO3-; food additive in doughs)
what does iodine content in food depend on and explain
on soil content
For fruit veg, animal products then they need to be grown in soil and feed with adequate iodine for the source to have adequate iodine
So if soil isn’t rich in iodine then food produced from this wont be rich in iodine
Mountainous areas have bad iodine levels. Particularly north Scotland
So if diet is locally based and iodine in local land is low then iodine consumption will be reduced
what 2 sources of food are high in iodine and explain why
Dairy products have become significant source – supplementation of feeds, sterilisation of teats
Seafood naturally rich and predictable source, as doesn’t depend on content in soil – seaweed 0.5mg/100 g; fish up to 0.3 mg/kg (saltwater not freshwater) (shell fish and seaweed have naturally high levels)
what are goitrogens
something which Interfere with uptake of iodide by thyroid gland, incorporation into T3/4 or secretion of T3/4
- thiocyanates (SCN-) – associated with plant foods
- perchlorates (ClO4-)- associated with plant food
- cyanoglucosides – associated with plant foods
- brassicas, cassava, maize, bamboo shoots, sweet potato, lima beans, Lithium
(Lithium helps treat depression and bipolar disorder so impacts there peoples iodine uptake)
(Cassava is staple in parts of Africa, this is where iodine deficiency is already a problem so this is making the problem worse , maize is staple in Latin America)
Only likely to be problematic where diet low in iodine
iodine requirements are related to what
to thyroid function
how much iodine do adults require to avoid severe deficiency and what happens if this isnt met
70 µg/d to avoid severe deficiency, (otherwise would develop goitre – adaptation of thyroid gland as not making enough t3/4 so causes swelling at base of neck)
iodine level in thyroid gland is normal at iodine intakes of what
100 µg/d
what is the RNI for iodine
140 µg/d
We need it in tiny quantities but on a daily basis
explain iodine deficiency disease (IDD)
Symptoms of hypothyroidism (underactive thyroid) however there are also other causes of hypothyroidism
Hypo = less than
So hypothyroidism is less thyroid hormones than should have. Individual will be come tired, less active and lethargic as have less energy and feel cold. So decreases fertility as don’t have enough energy to. And if sever enough then leads to goitre.
mental retardation, neonatal and infant deaths as lack of brain development, this is irreversible and can cause death
Estmated > 800 million people live in iodine-deficient environments as geographical area is iodine deficient (IDD endemic)
explain the WHOS recommendations in preventing iodine deficiency
WHO public health strategy for elimination of IDD is universal salt iodization (USI)
WHO recommends salt should contain 20–40 mg of iodine per kg of salt (provides 150 μg/day of iodine)
assumes average intake of salt per person per day is 10 g (exceeds the WHO recommended upper limit of 6 g salt/day)
WHO use salt to fortify with iodine as salt is needed in the diet
explain problems in relation to the WHOs recommendation in preventing iodine deficiency
Requirements to reduce salt intake is more of a problem here than increasing iodine consumption so wouldn’t be worth creating iodized salt
what countries have Less than 35 % of households with access to iodinated salt
russia
sudan
yemen
pakistan
afghanistan
