Iodine supplements needed?

[Guest guest]

Hi All & Lynn

 

Lynn Detamore wrote:

> phil, so is [human] iodine supplementation a good idea? well, x

> for us soymilk imbibers. lynn

 

Iodine (I) is an essential trace-element, needed for normal thyroid

function in animals and humans. Deficiency of I has its greatest adverse

effects on health / animal productivity during pregnancy, lactation and

(at least in animals) the reproductive phase. Iodine also is needed for

an effective immune response, especially in young animals.

 

I deficiency is the most common trace-element deficiency worldwide. It

is especially prevalent in the mountains and deserts and in plants grown

on volcanic soils.

 

An Irish medical report, released 03 Aug 2006, confirmed in humans

what we found in ruminants many years ago. It says: " Low Iodine Levels

In Irish Women Is A Cause For Concern During Pregnancy.. Irish

women of child-bearing age are not getting enough iodine in their diet,

which could harm the neuropsychological development of their unborn

foetus and impact on the intelligence quotient (IQ) of their children and

on the incidence of attention deficit and hyperactivity disorder (ADHD).

These preliminary results published recently in the Irish Journal of

Medical Science are from a research study carried out by a UCD

research team headed by Dr Peter Smyth, principal investigator in UCD

Conway Institute of Biomolecular & Biomedical Research and senior

lecturer in the UCD School of Medicine & Medical Science along with

his UCD colleague, Professor Colm O'Herlihy from the National

Maternity Hospital, Holles Street. The developing foetus does not

possess a functioning thyroid gland until 13-15 weeks gestation. It relies

solely on the presence of maternal thyroid hormones to ensure

neuropsychological development. In turn, the availability of these

hormones is dependant on an adequate supply of iodine in the diet of

the pregnant mother. " Also, the researchers found that maternal I

status is LOWER today than in the 1990s. For more details, see

http://www.medicalnewstoday.com/medicalnews.php?newsid=48668

 

http://www.theage.com.au/news/National/Children-at-risk-from-iodine-

deficiency/2006/02/19/1140283938400.html says: " Children at risk from

iodine deficiency. February 19, 2006. Almost half of all Australian

primary school children are mild to moderately iodine deficient, putting

their mental and physical development at risk, researchers say. When

the figures are broken down into states Victoria and NSW fare even

worse, while Western Australia and Queensland are the least affected.

The Australian National Iodine Nutrition Study of >1700 school children

from 88 schools has prompted the researchers to call for mandatory

iodisation of all edible salt in Australia, in line with the United States and

most European countries. Most iodine in food comes from seafood, milk

and iodised salt. Senior researcher Mu Li, of the University of NSW's

school of public health, and colleagues studied iodine levels in the early

morning urine samples of Year Four students in five mainland states

between July 2003 and December 2004. They found 46.3 per cent of all

students had iodine levels in the mild to moderately deficient range -

less than 100 micrograms per litre of urine. However, Dr Li said

significant and unexpected variations were reported across the

continent with children from Victoria, NSW and South Australia faring

worse than those in Western Australia and Queensland. More than 70

per cent of Victorian children, almost 60 per cent of those in NSW and

close to half the South Australian students were in the mild to moderate

iodine deficiency range. However, their counterparts in Western

Australia and Queensland were generally found to have sufficient iodine

levels under World Health Organisation (WHO) guidelines. " Children

living in Western Australia and Queensland are clearly ingesting more

iodine than their counterparts living elsewhere in Australia, " the

researchers wrote in the Medical Journal of Australia (MJA). "

 

http://www.scoop.co.nz/stories/GE0608/S00063.htm says: " NZFSA to

consider iodine fortification plans " . 16 August 2006, Press Release:

New Zealand Food Safety Authority. NZFSA to consider iodine

fortification plans. Concerns about iodine levels in our diet are

prompting health and nutrition experts to consider some new options for

fortification in an effort to curb rising rates of iodine deficiency disorders.

Food Standards Australia New Zealand (FSANZ) is seeking an

appropriate way to increase iodine in the New Zealand and Australian

food supply and is to issue a discussion paper this week which will seek

public submissions on how this can best be done. Jenny Reid, Assistant in the New Zealand Food Safety Authority's Food Standards

Group says: " NZFSA looks forward to receiving a copy of the report and

will be making a submission once we've read and considered the

options. " Low levels of iodine in New Zealand soils mean that the Kiwi

diet is naturally lacking in the nutrient which is essential for the cognitive

and intellectual development of unborn babies, infants and children.

Iodine deficiency can also cause goitre (enlargement of the thyroid

gland) among adults. " . For more detail, see the article.

 

The American NRC recommends a maximum of 1000ug (= 1mg) I/d as

safe for adult humans.

 

http://www.betterhealth.vic.gov.au/BHCV2/bhcarticles.nsf/pages/Iodine_

explained?open [an Australian Government site] says: Recommended

iodine intake is: 150ug/d for men; 120ug/d for women (175ug during

pregnancy, 200ug during breastfeeding); for most people, 50ug/d would

be an ample supplement.

 

[Phil's comment: Human nutritionists vary widely in their recommended

daily I intakes, from 50-1000ug/d for adult humans. However,

occasional supplementation at much higher levels (1-3mg (1000-

3000ug)/d should pose no problems.

 

Sources of iodine

 

Iodine is found in seawater, so any type of seafood is a rich source,

particularly seaweed (kelp). Since an adult only requires around one

teaspoonful of iodine over a lifetime, eating (SEA) fish once a week is

enough to fulfil the average iodine requirement.

 

[Phil's comment: Fish caught in inland waters have much less iodine in

their tissues than those caught at sea].

 

Although it comes from the ocean, sea salt is not a good source of

iodine.

 

Iodised salt is perhaps the most common source of iodine in the

Western diet and can provide enough iodine to avoid low thyroid

activity.

 

[Phil's comment: We advise 400-600 mg I/kg of balanced min-vit

mixture to be fed to all cows at 150-100 g/cow/d, incorporated into the

concentrate feed, or sprinkled over easy-feed silage for a 5-month

window (1 month before calving to 4 months after calving]

 

How to get enough iodine in your diet:

 

Seafood - dietitians recommend 2-3 meals of seafood/week to get the

beneficial fish oils. This will also provide you with a good source of

natural iodine.

 

Supplements - many multivitamin capsules and tablets supply 100-

150ug of iodine.

 

Some vegetables also contain iodine, but only if they are grown in

iodine-rich soils. Many regions of Australia, particularly Tasmania and

the Australian Capital Territory, have low levels of iodine in the soil.

 

[Phil's comment: Iodine-rich soils are very rare in Ireland; the norm is

low-iodine soils. Blood tests for PII (plasma inorganic iodine) in tens of

thousands of Irish cattle (1988-2001) show that circa 80-86% of cattle

not on an iodine suppplement are low to very low in iodine.

 

http://www.moh.govt.nz/moh.nsf/indexmh/iodine#3 says: " Dietary

sources of iodine include seafood (fish, shellfish and seaweed), iodised

salt, seameal custard, milk and eggs. The Ministry of Health¡¯s Food

and Nutrition Guidelines for Healthy Adults: A background paper

(Ministry of Health, 2003) recommend choosing iodised salt when using

salt, but do not recommend increasing overall salt intake. The iodine

content of, vegetables, fruits and grains generally reflect the iodine level

of the soil in which they were grown. The iodine content of New Zealand

soils is low and as a consequence locally produced foods are also low

in iodine. Iodine levels of meat, chicken, eggs and dairy products are

reflective of the iodine content of the animal feed used. Currently it is

difficult for most consumers to obtain adequate iodine from their normal

diet. Should supplements containing iodine be recommended to

consumers? NZFSA and MoH recommend that supplementation with

iodine should first be discussed with an appropriate health professional.

" .

 

In conclusion, those of you shun seafood, eggs or cow's milk might

consider taking routine supplements of 50-1000ug I daily, especially if

you are pregnant or nursing a baby. Also, parents of children who are

lethargic or " slow learners " , or have low IQ, might have their children's

blood or urine assessed for iodine status, and use an I supplement if

the tests show low iodine levels.

 

PS: Those interested in human trace-element nutrition may wish to

bookmark this URL:

http://www.food.gov.uk/multimedia/pdfs/vitmin2003.pdf

 

It has great data, including data on iodine. It says: " [iodine] Occurrence

in foods, food supplements and medicines: High levels of iodine are

present in marine fish (up to 2.5 mg/kg), shellfish (up to 1.6 mg/kg) and

sea salt (up to 1.4 mg/kg). Levels in cereals and grains vary depending

on the iodine content of the soil. The food colour erythrosine is also rich

in iodine. In the UK, iodine is also present in cows¡¯ milk (average

level 0.15 mg/kg), probably as a result of the use of supplemented

cattle feeds and iodophors as teat sterilants. The content of iodine in

raw food is reduced by cooking. Iodine, as iodide, is present in

multivitamin and mineral supplements (providing up to 0.49 mg

iodine/day) and is a component of kelp products. It is also present in

licensed medicines, topical antiseptics and radiographic contrast

agents. Iodine intakes in children are higher than those in adults,

because of a greater consumption of milk, and are likely to be higher in

the winter than the summer because winter milk contains more iodine.

Other sources of exposure: Iodine intake from water is estimated to be

generally less than 0.03 mg/day. Recommended amounts: COMA

established a Lower Reference Nutrient Intake (LRNI) and a RNI for

iodine of 0.07 and 0.14mg/day, respectively (COMA, 1991). " .

 

NOTE: National Advisory guidelines on trace-element supplements tend

to err on the conservative side. We usually exceed the " nationally

recommended intakes " for ruminants by a very considerable margin

and our monitoring of cattle on these higher levels has found no

adverse effects to date.

 

Best regards,