top Clinical Studies References
Iodine is a trace mineral, most of which is converted into iodide in the body. It aids in the development and functioning of the thyroid gland and is an integral part of thyroxin, a principal hormone produced by the thyroid gland. Iodine plays an important role in regulating the body's production of energy and excess fat burning capacity, promotes growth and development and stimulates the rate of metabolism. Mental acuity, speech and the condition of hair, nails, skin and teeth are dependent upon a well functioning thyroid gland.
Iodine may be beneficial in goitre, hypothyroidism, hyperthyroidism, exposure to radiation and fibrocystic breast disease.
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Published Clinical Studiesclin
Iodine deficiency in vegetarians and vegans.1
Krajcovicova-Kudlackova M, Buckova K, Klimes I, Sebokova E.
Institute of Preventive and Clinical Medicine, Slovak Academy of Sciences, Bratislava, Slovakia. kudlackova@upkm.sk
Iodine content in food of plant origin is lower in comparison with that of animal origin due to a low iodine concentration in soil. Urinary iodine excretion was assessed in 15 vegans, 31 lacto- and lacto-ovovegetarians and 35 adults on a mixed diet. Iodine excretion was significantly lower in alternative nutrition groups - 172 microg/l in vegetarians and 78 microg/l in vegans compared to 216 microg/l in subjects on a mixed diet. One fourth of the vegetarians and 80% of the vegans suffer from iodine deficiency (iodine excretion value below 100 microg/l) compared to 9% in the persons on a mixed nutrition. The results show that under conditions of alternative nutrition, there is a higher prevalence of iodine deficiency, which might be a consequence of exclusive or prevailing consumption of food of plant origin, no intake of fish and other sea products, as well as reduced iodine intake in the form of sea salt. Copyright 2003 S. Karger AG, Basel
Publication Types:
PMID: 12748410 [PubMed - indexed for MEDLINE]
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Micronutrient deficiencies and cognitive functioning.2
Black MM.
Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD 21201, USA. mblack@umaryland.edu
The relationship between four micronutrient deficiencies (iodine, iron, zinc and vitamin B-12) and children's cognitive functioning is reviewed. Iodine deficiency during pregnancy has negative and irreversible effects on the developing fetus. Although there is some evidence that postnatal iodine deficiency is associated with cognitive deficits, the findings are controversial. Iron deficiency is widespread and has been associated to cognitive deficits, but the results of prevention trials are inconsistent. Zinc deficiency has been linked with low activity and depressed motor development among the most vulnerable children. Associations with cognitive development are less clear and may be limited to specific neuropsychological processes. Vitamin B-12 deficiency has been associated with cognitive problems among the elderly, but little is known about its effect on children's cognitive functioning. Rates of vitamin B-12 deficiency are likely to be high because animal products are the only source of vitamin B-12. Although micronutrient deficiencies often co-occur in the context of poverty, little is known about the impact of multiple micronutrient deficiencies on cognitive development.
PMID: 14672291 [PubMed - indexed for MEDLINE]
Feto-maternal repercussions of iodine deficiency during pregnancy. An update.3
Glinoer D.
Universite Libre de Bruxelles, University Hospital Saint-Pierre, Department of Internal Medicine/Endocrinology, Thyroid Investigation Clinic 322, Rue Haute, B-1000 Brussels/Belgium. dglinoer@ulb.ac.be
The main changes in thyroid function associated with the pregnant state are increased thyroid hormone requirements. These increased requirements can only be met by a proportional increase in hormone production, that directly depends upon the availability of dietary iodine. When the iodine intake is adequate, normal "physiological" adaptation takes place. When the intake is restricted, physiological adaptation is progressively replaced by pathological alterations, in parallel with the degree of iodine deprivation, leading to excessive glandular stimulation, hypothyroxinemia, and goiter formation. Thus, pregnancy acts typically as a revelator of underlying iodine restriction and gestation results in an iodine deficient status, even in conditions with only a moderately restricted iodine intake, characteristic of many European regions. Iodine deficiency during pregnancy has important repercussions for both mother and fetus, namely thyroid underfunction and goitrogenesis. Furthermore, iodine deficiency may be associated with alterations of the psychoneuro-intellectual outcome in the progeny. The risk of an abnormal progeny's development is further enhanced because mother and offspring are exposed to iodine deficiency, both during gestation and the postnatal period. Because iodine deficiency is still prevalent in many European regions and remains a subject of great concern, investigators have proposed, since several years, that iodine prophylaxis be introduced systematically during pregnancy, in order to provide mothers with an adequate iodine supply. In areas with a severe iodine deficiency, correcting the iodine lack has proved highly beneficial to prevent mental deficiency disorders. The many actions undertaken to eradicate severe iodine deficiency have allowed to prevent the occurrence of mental retardation in millions young infants throughout the world. In most public health programmes dealing with the correction of iodine deficiency disorders, iodized salt has been used as the preferred strategy in order to convey the iodine supplements to the household. Iodized salt, however, is not the ideal vector in the specific instance of pregnancy (or breastfeeding) or in young infants, because of the necessity to limit salt intake. Hence, particular attention is required in our countries to ensure that pregnant women have an adequate iodine intake, by administering multi-vitamin tablets containing iodide supplements (+125 micro g/d). Finally, it is with some concern that the results of a recent nutritional survey in the USA have disclosed that iodine deficiency, long thought to have been eradicated since many years, may actually show a resurgence, particularly in women in the child-bearing period. This issue needs to be considered seriously by the medical community and public health authorities.
PMID: 12707632 [PubMed - indexed for MEDLINE]
Mild iodine deficiency in a sample of New Zealand schoolchildren.4
Skeaff SA, Thomson CD, Gibson RS.
Department of Human Nutrition, University of Otago, Dunedin, New Zealand. sheila.skeaff@stonebow.otago.ac.nz
OBJECTIVE: To assess the iodine status of New Zealand schoolchildren. DESIGN: A proportionate to population size school-based cluster survey was used to randomly select children from two cities. The indicators used to assess iodine status were urinary iodine, as determined in a casual urine sample, and thyroid volume, as measured by ultrasonography. A qualitative food frequency questionnaire designed to ascertain frequency of consumption over the previous 3 months of foods or food groups that are good sources of dietary iodine, including iodized salt, was administered to each child. SETTING: Dunedin and Wellington, New Zealand. PARTICIPANTS: Three-hundred children aged 8-10 y from 30 schools. RESULTS: The median urinary iodine concentration of the children was 6.6 micro g/dl (interquartile range, 4.5-9.1). The percentage of children who had urinary iodine levels less than 5 micro g/dl was 31.4 (95% confidence interval (CI), 24.2-38.6). Comparison of thyroid volume with 2001 World Health Organization age/sex-specific and age/BSA-specific cut-off values resulted in a goitre prevalence of 11.3% (95% CI, 7.6-15.1) and 12.0% (95% CI, 7.9-16.1), respectively. Almost 30% of the children's caregivers did not use iodized salt in cooking and 51% of the children did not use iodized salt at the table. CONCLUSIONS: Mild iodine deficiency was found in this sample of children. Iodized table salt may no longer be making a significant contribution to the iodine intakes of New Zealand children.
PMID: 12494301 [PubMed - indexed for MEDLINE]
Iodine deficiency disorders.5
Elliott TC.
PIP: Iodine deficiency disorder (IDD) affects 800 million people in the world, yet iodine supplementation is one of the most cost-effective nutritional interventions known. Iodine is incorporated into thyroid hormones, necessary for regulating metabolic rate, growth, and development of the brain and nervous system. IDD may appear as goiter in adults, usually not a serious problem, or in cretinism in children, which is marked by severe mental and physical retardation, with irreversible hearing and speech defects and either deaf-mutism, squint and paralysis, or stunting and edema. Children supplemented by age 1 or 2 can sometimes be helped. Foods contain variable amounts of iodine dependent on the soil where they are grown, hence mountainous and some inland regions have high goiter and IDD incidence. There are also goitrogenic foods, typically those of the cabbage family. Diagnosis is clinical or by blood tests for thyroid hormone levels and ratios. Finger-stick methods are available. Prevention of IDD is simple with either iodized salt or flour, iodinated central water supplies, injectable or oral iodine-containing oil. All cost about $.04 per person per year, except injections, which cost about $1 per person, but have the advantage that they could be combined with immunizations. Local problems with supplements are loss of iodine in salt with storage in tropics, and local production of cheaper uniodinated salt. Emphasis should be given to pregnant women and young children. There is no harm in giving pregnant women iodine injections in 2nd or 3rd trimester.
PMID: 12343033 [PubMed - indexed for MEDLINE]
Control of iodine deficiency in Western and Central Europe.6
Delange FM.
Executive Director and Regional Coordinator emeritus for Europe of the International Council for Control of Iodine Deficiency Disorders (ICCIDD), Department of Pediatrics, University of Brussels, Brussels, Belgium. fdelange@ulb.ac.be
The paper summarizes the updated information published in peer review journals on the status of iodine deficiency in Western and Central Europe. Nationwide evaluations of the prevalence of goiter and of the concentrations of urinary iodine were conducted during recent years in 17 of the 31 countries of Western and Central Europe, mostly in school-aged children. Fourteen of the 31 countries had reached a normal status of iodine nutrition, three countries were close to iodine sufficiency, iodine deficiency persisted in 13 other countries and data are missing for Albania. The most important alterations of thyroid function due to iodine deficiency in Europe occur in neonates and very young infants. The major measure for the prevention of iodine deficiency is the fortification of all salt for human and animal consumption and for the food industry. The recommended daily intake of iodine for all ages in all inhabitants in Europe are as follows: 90 microg/day from 0 to 59 month, 120 microg/day between 6 and 12 years, 100 microg/day in adolescents and adults and 200 microg/day in pregnant and lactating women. The main guidelines for the correction of iodine deficiency in Europe are included.
PMID: 14514161 [PubMed - indexed for MEDLINE]
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