What is it and why is it important? - milk.co.uk
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A guide for health professionals What is it and why is it important?
Contents Overview
1 Overview Most people will recognise iodine from science
2 A little bit of history experiments in school, but it is also an essential
micronutrient that has many roles in the body.
5 Growth and development
7 Dairy and iodine Iodine makes up part of the thyroid hormones which help release
energy from food and regulate growth in children. They also
8 Recommended intake contribute to brain and nerve function, and help maintain skin health.
10 Other food sources of iodine
13 Supplementation and excess iodine
MAINTAINS RELEASES
SKIN ENERGY
FROM FOOD
IODINE
HELPS BRAIN REGULATES
AND NERVE GROWTH IN
FUNCTION CHILDREN
1
A little bit of history
Certain population groups in the UK are classified as
mildly iodine deficient by the World Health Organisation.
During the 1800s and 1900s iodine deficiency was
common in some parts of the UK. Goitre was common in
many parts of Britain, including South-West England and
Wales; it was so common in the Peak District that it was
termed ‘Derbyshire Neck’.
Goitre is a condition where the thyroid gland becomes
enlarged due to insufficient or excess iodine. Iodine
deficiency can lead to thyroid dysfunction, including
both hypothyroidism and hyperthyroidism. Symptoms of
hypothyroidism include weight gain, dry skin, hair loss,
tiredness, depression and intolerance to cold.
2 3
Growth and development
Pregnancy and breastfeeding
During pregnancy the thyroid hormones play a role in
brain development and growth of the unborn baby. Severe
iodine deficiency in pregnancy, which is rare in the UK, can
compromise brain development leading to problems with
cognition, hearing, speech and growth. Mild-to-moderate
iodine deficiency in pregnancy has been linked to lower IQ
and reading ability in children.
It’s a good idea for women to consume enough iodine
whether planning a baby or not, as pregnancies can often
28% be unplanned.
However, too much iodine can also cause problems and it is
important to avoid excessive intake of iodine (see page 13).
of girls
aged 11-18 & 1 in 10 adult women
DON’T GET ENOUGH IODINE FROM FOOD SOURCES*
Studies have found mild iodine deficiency in some UK teenage
girls and pregnant women.
* Data from the National
4 Diet & Nutrition Survey 5
Dairy and iodine
The iodine content of foods can vary depending on
the soil or waters in which they were grown.
Animals that graze on grass from nutrient poor soil are also
at risk of becoming deficient in iodine. In fact, in the
1930s dairy farmers in the UK added iodine to cattle feed to
improve animal health. This resulted in an increase in the
iodine content of milk and dairy products. These days, dairy
foods are one of the main providers of iodine to the UK diet.
Childhood and adolescence Consuming milk, yogurt and cheese is a great way to help
to meet iodine requirements. There is no difference in the
Children and teenagers grow and develop rapidly up until iodine content between whole, semi-skimmed or skimmed
the age of around 18 years. milk, however, it does vary throughout the year and can
range from 20μg – 41μg per 100g. It is higher in the winter
Iodine forms part of the thyroid hormones which are due to supplementation of iodine in animal feed.
responsible for regulating metabolic rate, as well as
physical and mental development in children and teenagers. The table on the next page shows the recommended iodine
Poor intakes during childhood may be linked to a low IQ intake at different stages in life, and the portion sizes of
and poor physical growth. dairy that can help meet those needs.
6 7
53
I
Iodine
Iodine recommendations by age group
126.904
Iodine needs Iodine
Pregnancy & Breastfeeding Age (RNI* µg/day) Portion sizes content**(µg)
The Department of Health 1- 3 years 70 100ml whole milk 30
recommendation for pregnant 60g whole plain yogurt 38
and breastfeeding women 15g cheddar cheese 4.5
is the same as for adults These portion sizes provide approximately 72µg of iodine
(140μg/day). However, WHO
recommends 250μg/day. 4 -6 years 100 A small carton (189ml) semi-skimmed milk 57
(See page 13 for information 80g whole plain yogurt 50
on supplements.) 20g cheddar cheese 6
These portion sizes provide approximately 113µg of iodine
* RNI, Reference Nutrient Intake, is a
7-10 years 110 A small carton (189ml) semi-skimmed milk 57
figure set by the Department of Health, 125g low-fat plain yogurt 43
based on the minimum requirements for
iodine plus a margin of safety to allow for 20g cheddar cheese 8
different dietary patterns. These portion sizes provide approximately 107µg of iodine
** Nutrient values for iodine in milk vary
throughout the year, the figure given here 11-14 years 130 200ml semi-skimmed milk 60
is based on an average amount. 150g low-fat plain yogurt 51
μg - microgram, or one thousandth of a 30g cheddar cheese 9
milligram.
These portion sizes provide approximately 120µg of iodine
15-18 years 140 250ml semi-skimmed milk 75
200g low-fat plain yogurt 68
30g cheddar cheese 9
These portion sizes provide approximately 152µg of iodine
19+ years 140 200ml semi-skimmed milk 60
150g low-fat plain yogurt 51
30g cheddar cheese 9
These portion sizes provide approximately 120µg of iodine
8 9
Other
food sources
of iodine
per adult portion: White fish (115µg) Oily fish** (50µg)
Anyone with a medically
diagnosed allergy to any
of these foods should
avoid consuming them.
* Children under five years old
shouldn’t be given whole
nuts because of the risk of
choking.
Shellfish (90µg) Eggs (25µg) Beef (10µg - 15µg) ** Pregnant women should
limit their oily fish intake
during pregnancy to 2
portions per week.
See the British Dietetic
Association Factsheet on
Iodine for further information
on other food sources of iodine
https://www.bda.uk.com/
foodfacts/Iodine.pdf
Peanuts* (5µg) Seaweed
(see page 13) (1g dried nori) (29µg - 46µg)
Dairy based recipes
(10µg - 65µg)
11
Supplementation
and excess iodine
Most people should be able to get all the iodine they need by
eating a balanced and varied diet. Too much iodine in the diet can
cause symptoms similar to iodine deficiency, including goitre and
hormone imbalance.
Daily iodine intake should not exceed 600μg for adults and
It’s all pregnant women. The upper limit for children aged 1-10 years
ranges from 200μg – 300μg and 450μg – 500μg for teens. If
about
taking supplements, the iodine content should not exceed the
RNI for that age group.
good Kelp supplements are not recommended especially during
pregnancy, as they are high in iodine. Seaweed should also be
balance consumed sparingly during pregnancy and less than once per
week. If taking supplements during pregnancy they should not
exceed daily amounts of 150µg.
12 13
Information sources
Bath SC, Rayman MP. BDA (2016) Food Factsheet – Iodine
https://www.bda.uk.com/resource/iodine.html [accessed 1/2021]
Threapleton DE et al. (2020). Prenatal and Postpartum Maternal Iodide Intake from Diet and
Supplements, Urinary Iodine and Thyroid Hormone Concentrations in a Region of the United
Kingdom with Mild-to-Moderate Iodine Deficiency.
Nutrients. 2021; 13(1):230.
Bates B et al (2020). National Diet and Nutrition Survey Results from Years 9 and 11
(combined) of the Rolling Programme (2016/2017 – 2018/2019)
https://www.gov.uk/government/statistics/ndns-results-from-years-9-to-11-2016-to-2017-and-
2018-to-2019 [accessed 1/2021]
Public Health England (2016). Government recommendations for energy and nutrients for males
and females aged 1 – 18 years and 19+ years.
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/
file/618167/government_dietary_recommendations.pdf [accessed 1/2021]
Finglas PM et al (2015) McCance and Widdowson’s The Composition of Foods,
Seventh Summary edition, Cambridge: Royal Society of Chemistry
NHS Choices. Underactive thyroid (hypothyroidism).
https://www.nhs.uk/conditions/underactive-thyroid-hypothyroidism/causes/ [accessed 1/2021]
NHS Choices. Overactive thyroid (hyperthyroidism) – Symptoms
https://www.nhs.uk/conditions/overactive-thyroid-hyperthyroidism/symptoms/ [accessed
1/2021]
Tolerable upper intake levels for vitamins and minerals, EFSA (2006)
http://www.efsa.europa.eu/sites/default/files/efsa_rep/blobserver_assets/ndatolerableuil.pdf
[accessed 1/2021]
Vanderpump MP et al. Iodine status of UK schoolgirls: a cross-sectional survey. Lancet. 2011;
377(9782): 2007-12
Bath SC et al. (2013). Effect of inadequate iodine status in UK pregnant women on cognitive
outcomes in their children: results from the Avon Longitudinal Study of Parents and Children
(ALSPAC). Lancet; 382(9889): 331-7
For details on additional information sources please contact Dairy UK
Tel +44 (0)20 7405 1484
nutrition@dairyuk.org
Last reviewed: 01/2021
© Dairy UK 2021 Next review due: 01/2023
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