Miracon Science

Iodine

Synonym(s): iodine, iodide, potassium iodide, potassium iodide
Nutrient group: Minerals & trace elements

Sources and physiological effects

Dietary sources

Iodine is mainly found in fatty marine fish, e.g. turbot, haddock, cod. Plant iodine sources are marine algae, such as the bladderwrack (Fucus vesiculosus). Other sources: iodised table salt, sometimes milk (contamination: when iodine-containing detergents are used in the milking equipment). The iodine concentration in foodstuffs depends on the iodine content of the soil. The Alpine region is an iodine deficient area, which is why locally produced food usually contains little iodine; see below for the consequences. Iodide is highly soluble in water (losses due to boiling water). Cruciferous plants such as cabbage, radish, cress, mustard, etc. contain goitrogens that inhibit iodine uptake. However, this is only problematic in the case of long-term consumption of large quantities (e.g. 400 g white cabbage or 2 kg Chinese cabbage or 2.8 kg radish daily over several months).
Physiological effects
Thyroid function
  • Iodine is a component of the thyroid hormones L-thyroxine (T4) and triiodothyronine (T3), which control a variety of functions.
  • Thyroid hormones regulate the basal metabolic rate (increased basal metabolic rate in hyperthyroidism, reduced basal metabolic rate in hypothyroidism).
Metabolism
  • Control of protein, carbohydrate and fat metabolism
Temperature regulation
  • Regulation of the sensation of warmth/cooling
Energy metabolism
  • Influence on the mitochondrial respiratory chain and oxygen turnover
Growth
  • Control of physical and mental development
Organ development
  • Regulation of fetal development of the nervous system and bones
  • Influences cell division and cell differentiation 

EFSA Health Claims

Health Claims EFSA Opinion
Iodine
  • Contributes to normal cognitive function
  • Contributes to normal a energy metabolism
  • Contributes to a normal function of the nervous system
  • Contributes to normal production of thyroid hormones and normal thyroid function

Contributes to the maintenance of normal skin

  

Recommended intake

D-A-CH reference values for the intake of iodine (Reference values EFSA and NHI  )
  Age Iodine (µg/d)
Infants (months)
  0-4  40
  4-12  80
Children (years)
  1-4  100
  4-7  120
  7-10  140
  10-13  180
  13-15  200
Teenagers/adults (years) Women Men
  15-19 200 200
  19-25  200  200
  25-51  200  200
  51-65  180  180
  > 65  180  180
Pregnant women 230
Breast-feeding women 260
Groups with increased needs Sports, high temperature working environments
(Iodine loss in sweat: 30-40 µg/l)
Special group at risk of deficiency  Vegans, pregnant women, nursing mothers, athletes, growing adolescents,
high tea/coffee consumption, lack of iodized salt

 

Recommended intake according to food labelling regulations  
(=100% TB marking on label) 150 µg
Nutrient safety  
UL
 

Long-term daily intake at which no negative health effects are to be expected negative effects on health are to be expected

 < 1100 µg/d (according to NIH)
NOAEL
 		 Maximum intake, with no observed adverse effect 1000 - 1200 µg/d

Status according to Austrian Nutrition Report 2012

Iodine status in children

Fig. 1: Iodine status evaluation and evaluation of the thyroid hormones triiodothyronine and tetraiodothyronine in comparison to iodine intake in school children (7 - 14 years), by sex
 
Iodine status in adults

Fig. 2: Iodine status evaluation and evaluation of the thyroid hormones triiodothyronine and tetraiodothyronine in comparison to iodine intake in adults (18 - 64 years), by sex
 
Iodine status for seniors

Fig. 3: Iodine status evaluation and evaluation of the thyroid hormones triiodothreonine and tetraiodothyronine in comparison to iodine intake in seniors (65 - 80 years), by sex

Detailed information

Iodine deficiency in apline region

The Alpine states are areas of iodine deficiency. The enrichment of table salt led to an improved iodine supply to the population. However the results of the 12th nutrition report of the German Society for Nutrition e.V. (DGE) show, that the iodine status of the population is once again gradually deteriorating. The results of the DONALD study (1) published in the nutrition report show that the iodine intake of children in Germany is not satisfactory. More than half of six to twelve year olds do not reach the recommended iodine intake. According to the Austrian Nutrition Report 2012 (2), 30% of women and 39% of men in Austria also have a lower iodine status. The same applies to the iodine intake of the adult German population, which is currently in a lower desirable range (3).
 
Increased iodine requirements during pregnancy and lactation
Due to an increased basal metabolic rate, an increase in the distribution volume and increased iodine secretion via the kidneys, the daily requirement of iodine during pregnancy rises from 200 to 230 micro;g, and even to 260 micro;g (4) (5) during breastfeeding. In addition, from the 12th week of pregnancy, the thyroid gland of the fetus begins its own hormone synthesis. Even a slight iodine deficiency increases the risk of abnormal brain and nerve development in the unborn child (4). To avoid iodine deficiency, a daily supplementation of iodine is recommended. The increased requirement can no longer be covered by the use of iodised table salt during pregnancy and lactation, especially as pregnant women should reduce their salt intake due to tendency to edema. Adequate iodine intake, starting in early pregnancy, can compensate for an existing mild iodine deficiency and prevent the formation of goitre in both the mother and the newborn.6
 
CAVE: High-dose iodine preparations for radiation protection
Iodine preparations for the protection of the thyroid gland in reactor accidents have an extremely high iodine content (36 mg = 36000 µg iodine) and are not suitable for prevention. These preparations such as the product “potassium iodide“ of the Austrian company Lannacher are to be used only for the application with acute radioactive contamination in case of disaster and should be administrated only after explicit instruction by health authorities.
 
Iodine from marine algae - sustainable and valuable

Due to overfishing and the associated decimation of biodiversity and overexploitation of natural resources, marine algae are increasingly coming into focus as natural sources of iodine. The brown algae Ascophyllum nodosum, also known as kelp, is a particularly valuable iodine supplier in terms of sustainability and can contribute to the daily iodine supply as an optimally dosed supplement. The PureSea® brand raw material is obtained off the Outer Hebrides, a largely unspoiled Scottish natural landscape. The high-quality kelp powder is standardized to a constant iodine content. The naturidente form of the trace element enables optimal bioavailability.7

Reference values

Parameter Substrate Description
Iodine excretion (µg iodine/g) Urine Since iodine uptake and iodine secretion are balanced under equilibrium conditions, the measurement iodine excreted in urine is an established method for excretion for determining the status.
GANZIMMUN measures µg iodine/g creatinine to take kidney performance (urine volume) into account.
Interpretation
Normal status (>100 µg iodine/l) No evidence of iodine-deficient hypothyroidism
Mild iodine deficiency (50 - 100 µg iodine/l) Increased frequency of struma, normal mental and physical development
Moderate iodine deficiency (25 - 50 µg iodine/l) Significantly increased frequency of struma, risk of hypothyroidism, but no manifest risk of cretinism yet
Severe iodine deficiency (<25 µg iodine/l) High risk of hypothyroidism, serious risk of cretinism

Deficiency symptoms

Impact on Symptomes
General health Weight gain, lack of concentration, sensitivity to cold, constipation, fatigue, sleep disorders
Thyroid gland Struma formation, increased risk of autoimmune thyroid diseases
Cardiovascular system Palpitations
Metabolism Elevated blood lipid levels
Skin/Hair Dry, rough skin and hair
Women Cycle disorders, increased risk of breast cancer
Men Fertility problems
Children Juveniles Struma, learning and concentration disorders
Pregnancy Increased miscarriage rate and infant mortality, fetal malformations, cretinism, hearing defects

Indications

Effect Indication Dosage

Physiological effects
at a low intake

 Ensuring iodine supply in case of increased demand (e.g. pregnancy and lactation period, sports) or a diet low in iodine (e.g. no iodised salt, no sea fish) 200 µg/d
For the targeted dietary treatment of latent or specific deficiency symptoms such as iodine deficiency goiter 200 µg/d
To cover a diagnosed iodine deficiency, for example as a result of an unbalanced diet without iodized salt 100 - 200 µg/d

Administration

General mode of administration
 
When
 		 Iodine should be taken after meals to minimize interactions with food components.
Side effects
At very high doses (>300 µg) hyperthyroid conditions can be caused by stimulation of the thyroid gland (such as tachycardia, sweating).
Contraindications
Manifest and latent hyperthyroidism (e.g. Graves' disease, Hashimoto's thyroiditis), focal and diffuse thyroid autonomies, autonomic adenomas (>300 µg)

Interactions

Drug and nutrient interactions
Iodine Reduces the effect of thyrostatic drugs
Iron deficiency (serum ferritin <12 µg/l) May affect the efficiency of iodine substitution

Description and related substances

Description
Trace mineral
Related Substances
  • Sodium iodide
  • Sodium iodate
  • Potassium iodide
  • Potassium iodate
     

Iodides and iodates are similarly bioavailable.

References

References

1 Buyken, A. E. et al. 2012. Die DONALD Kohorte. Ein aktueller Überblick zu 25 Jahren Forschung im Rahmen der Dortmund Nutritional and Anthropometric Longitudinally Designed Study. Bundesgesundheitsblatt. 55:875-884.
2 Österreichischer Ernährungsbericht 2012.
3 Völzke, H., Thamm, M. 2007. Epidemiologie von Schilddrüsenerkrankungen in Deutschland. Prävention und Gesundheitsförderung. 2:149-152.
4 Hahn, A. et al. 2006. Ernährung. Physiologische Grundlagen, Prävention, Therapie.
5 Gröber, U. 2008. Orthomolekulare Medizin. Ein Leitfaden für Apotheker und Ärzte. Wissenschaftliche Verlagsgesellschaft.
6 Leo, S. D. et al. 2016. Iodine Supplementation in Women during Preconception, Pregnancy, and Lactation: Current Clinical Practice by U.S. Obstetricians and Midwives. Thyroid.
7 Lehvoss Nutrition. Seaweed for Cognitive Health. https://www.lehvossnutrition.com/images/glproducts_docs/brands/Seaweed_for_Cognitive_Health_-Scientific_Review_-_Lehvoss.pdf.

References Interactions
Stargrove, M. B. et al. Herb, Nutrient and Drug Interactions: Clinical Implications and Therapeutic Strategies, 1. Auflage. St. Louis, Missouri: Elsevier Health Sciences, 2008.
Gröber, U. Mikronährstoffe: Metabolic Tuning –Prävention –Therapie, 3. Auflage. Stuttgart: WVG Wissenschaftliche Verlagsgesellschaft Stuttgart, 2011.
Gröber, U. Arzneimittel und Mikronährstoffe: Medikationsorientierte Supplementierung, 3. aktualisierte und erweiterte Auflage. Stuttgart: WVG Wissenschaftliche Verlagsgesellschaft Stuttgart, 2014.
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