The role of iodine in human growth and development.
01 Aug 2011-Seminars in Cell & Developmental Biology (Semin Cell Dev Biol)-Vol. 22, Iss: 6, pp 645-652
TL;DR: Iodine prophylaxis of deficient populations with periodic monitoring is an extremely cost effective approach to reduce the substantial adverse effects of iodine deficiency throughout the life cycle.
About: This article is published in Seminars in Cell & Developmental Biology.The article was published on 2011-08-01. It has received 295 citations till now. The article focuses on the topics: Iodine deficiency & Cretinism.
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TL;DR: This guideline has been produced as the official statement of the European Thyroid Association guideline committee and indicates that targeted antenatal screening for thyroid function will miss a substantial percentage of women with thyroid dysfunction.
Abstract: This guideline has been produced as the official statement of the European Thyroid Association guideline committee. Subclinical hypothyroidism (SCH) in pregnancy is defined as a thyroid-stimulating hormone (TSH) level above the pregnancy-related reference range with a normal serum thyroxine concentration. Isolated hypothyroxinaemia (defined as a thyroxine level below the 2.5th centile of the pregnancy-related reference range with a normal TSH level) is also recognized in pregnancy. In the majority of SCH the cause is autoimmune thyroiditis but may also be due to iodine deficiency. The cause of isolated hypothyroxinaemia is usually not apparent, but iodine deficiency may be a factor. SCH and isolated hypothyroxinaemia are both associated with adverse obstetric outcomes. Levothyroxine therapy may ameliorate some of these with SCH but not in isolated hypothyroxinaemia. SCH and isolated hypothyroxinaemia are both associated with neuro-intellectual impairment of the child, but there is no evidence that maternal levothyroxine therapy improves this outcome. Targeted antenatal screening for thyroid function will miss a substantial percentage of women with thyroid dysfunction. In children SCH (serum TSH concentration >5.5-10 mU/l) normalizes in >70% and persists in the majority of the remaining patients over the subsequent 5 years, but rarely worsens. There is a lack of studies examining the impact of SCH on the neuropsychological development of children under the age of 3 years. In older children, the evidence for an association between SCH and impaired neuropsychological development is inconsistent. Good quality studies examining the effect of treatment of SCH in children are lacking.
492 citations
TL;DR: This review examines the current evidence for a possible connection between nutritional intake (including micronutrients and whole diet) and neurocognitive development in childhood and concludes that malnutrition can impair cognitive development, whilst breastfeeding appears to be beneficial for cognition.
Abstract: This review examines the current evidence for a possible connection between nutritional intake (including micronutrients and whole diet) and neurocognitive development in childhood. Earlier studies which have investigated the association between nutrition and cognitive development have focused on individual micronutrients, including omega-3 fatty acids, vitamin B12, folic acid, choline, iron, iodine, and zinc, and single aspects of diet. The research evidence from observational studies suggests that micronutrients may play an important role in the cognitive development of children. However, the results of intervention trials utilizing single micronutrients are inconclusive. More generally, there is evidence that malnutrition can impair cognitive development, whilst breastfeeding appears to be beneficial for cognition. Eating breakfast is also beneficial for cognition. In contrast, there is currently inconclusive evidence regarding the association between obesity and cognition. Since individuals consume combinations of foods, more recently researchers have become interested in the cognitive impact of diet as a composite measure. Only a few studies to date have investigated the associations between dietary patterns and cognitive development. In future research, more well designed intervention trials are needed, with special consideration given to the interactive effects of nutrients.
396 citations
Cites background from "The role of iodine in human growth ..."
...Thyroid hormones play an important role in neurodevelopment and numerous neurological processes including neuronal cell differentiation, maturation and migration, myelination, neurotransmission, and synaptic plasticity (Zimmermann, 2009, 2011; Melse-Boonstra and Jaiswal, 2010)....
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...Nutrients provide building blocks that play a critical role in cell proliferation, DNA synthesis, neurotransmitter and hormone metabolism, and are important constituents of enzyme systems in the brain (Bhatnagar and Taneja, 2001; Lozoff and Georgieff, 2006; Zeisel, 2009; De Souza et al., 2011; Zimmermann, 2011)....
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...The association between mild-moderate maternal iodine deficiency and cognitive development is not as clear as it is when iodine deficiency is severe (Forrest, 2004; Zimmermann, 2007, 2009, 2011; Melse-Boonstra and Jaiswal, 2010)....
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...…degree of cognitive impairment (when compared to children from iodine sufficient areas), and iodine supplementation trials in school age children have provided some promising results with respect to improvement of some cognitive processes (Zimmermann, 2007, 2011; MelseBoonstra and Jaiswal, 2010)....
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...…building blocks that play a critical role in cell proliferation, DNA synthesis, neurotransmitter and hormone metabolism, and are important constituents of enzyme systems in the brain (Bhatnagar and Taneja, 2001; Lozoff and Georgieff, 2006; Zeisel, 2009; De Souza et al., 2011; Zimmermann, 2011)....
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TL;DR: FGR and unimproved sanitation are the leading risk factors for stunting in developing countries and reducing the burden of stunting requires a paradigm shift from interventions focusing solely on children and infants to those that reach mothers and families and improve their living environment and nutrition.
Abstract: Background
Stunting affects one-third of children under 5 y old in developing countries, and 14% of childhood deaths are attributable to it. A large number of risk factors for stunting have been identified in epidemiological studies. However, the relative contribution of these risk factors to stunting has not been examined across countries. We estimated the number of stunting cases among children aged 24–35 mo (i.e., at the end of the 1,000 days’ period of vulnerability) that are attributable to 18 risk factors in 137 developing countries.
308 citations
TL;DR: A decision tree approach is proposed that enables a risk assessment of substances present in food intended for infants below 16 weeks of age and the approach to be taken for the risk assessment are on a case‐by‐case basis, depending on whether the substance is added intentionally to food and is systemically available.
Abstract: Following a request from the European Commission to EFSA, the EFSA Scientific Committee (SC) prepared a guidance for the risk assessment of substances present in food intended for infants below 16 weeks of age. In its approach to develop this guidance, the EFSA SC took into account, among others, (i) an exposure assessment based on infant formula as the only source of nutrition; (ii) knowledge of organ development in human infants, including the development of the gut, metabolic and excretory capacities, the brain and brain barriers, the immune system, the endocrine and reproductive systems; (iii) the overall toxicological profile of the substance identified through the standard toxicological tests, including critical effects; (iv) the relevance for the human infant of the neonatal experimental animal models used. The EFSA SC notes that during the period from birth up to 16 weeks, infants are expected to be exclusively fed on breast milk and/or infant formula. The EFSA SC views this period as the time where health-based guidance values for the general population do not apply without further considerations. High infant formula consumption per body weight is derived from 95th percentile consumption. The first weeks of life is the time of the highest relative consumption on a body weight basis. Therefore, when performing an exposure assessment, the EFSA SC proposes to use the high consumption value of 260 mL/kg bw per day. A decision tree approach is proposed that enables a risk assessment of substances present in food intended for infants below 16 weeks of age. The additional information needed when testing substances present in food for infants below 16 weeks of age and the approach to be taken for the risk assessment are on a case-by-case basis, depending on whether the substance is added intentionally to food and is systemically available.
118 citations
Cites background from "The role of iodine in human growth ..."
...Disruptions in thyroid signalling can have widespread effects on infant development (Zimmermann, 2011)....
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TL;DR: Maternal supplementation within recommended safe intakes in populations with dietary deficiencies may prevent many brain and central nervous system malfunctions and even enhance brain development and function in their offspring.
Abstract: Scientific literature is increasingly reporting on dietary deficiencies in many populations of some nutrients critical for foetal and infant brain development and function. Purpose: To highlight the potential benefits of maternal supplementation with docosahexaenoic acid (DHA) and other important complimentary nutrients, including vitamin D, folic acid and iodine during pregnancy and/or breast feeding for foetal and/or infant brain development and/or function. Methods: English language systematic reviews, meta-analyses, randomised controlled trials, cohort studies, cross-sectional and case-control studies were obtained through searches on MEDLINE and the Cochrane Register of Controlled Trials from January 2000 through to February 2012 and reference lists of retrieved articles. Reports were selected if they included benefits and harms of maternal supplementation of DHA, vitamin D, folic acid or iodine supplementation during pregnancy and/or lactation. Results: Maternal DHA intake during pregnancy and/or lactation can prolong high risk pregnancies, increase birth weight, head circumference and birth length, and can enhance visual acuity, hand and eye co-ordination, attention, problem solving and information processing. Vitamin D helps maintain pregnancy and promotes normal skeletal and brain development. Folic acid is necessary for normal foetal spine, brain and skull development. Iodine is essential for thyroid hormone production necessary for normal brain and nervous system development during gestation that impacts childhood function. Conclusion: Maternal supplementation within recommended safe intakes in populations with dietary deficiencies may prevent many brain and central nervous system malfunctions and even enhance brain development and function in their offspring.
109 citations
Cites background from "The role of iodine in human growth ..."
...Moderate-to-severe iodine deficiency during pregnancy also increases rates of spontaneous abortion, reduces birth weight, and increases infant mortality [84]....
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References
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TL;DR: The DRIs represent the new approach adopted by the Food and Nutrition Board to providing quantitative estimates of nutrient intakes for use in a variety of settings, replacing and expanding on the past 50 years of periodic updates and revisions of the Recommended Dietary Allowances.
Abstract: Dietary Reference Intakes (DRIs) represent the new approach adopted by the Food and Nutrition Board to providing quantitative estimates of nutrient intakes for use in a variety of settings, replacing and expanding on the past 50 years of periodic updates and revisions of the Recommended Dietary Allowances (RDAs). The DRI activity is a comprehensive effort undertaken to include current concepts about the role of nutrients and food components in long-term health, going beyond deficiency diseases. The DRIs consist of 4 reference intakes: the RDA, which is to be used as a goal for the individual; the Tolerable Upper Intake Level (UL), which is given to assist in advising individuals what levels of intake may result in adverse effects if habitually exceeded; the Estimated Average Requirement (EAR), the intake level at which the data indicate that the needs for 50% of those consuming it will not be met; and the Adequate Intake (AI), a level judged by the experts developing the reference intakes to meet the needs of all individuals in a group, but which is based on much less data and substantially more judgment than that used in establishing an EAR and subsequently the RDA. When an RDA cannot be set, an AI is given. Both are to be used as goals for an individual. Two reports have been issued providing DRIs for nutrients and food components reviewed to date: these include calcium and its related nutrients: phosphorus, magnesium, vitamin D, and fluoride; and most recently, folate, the B vitamins, and choline. The approaches used to determine the DRIs, the reference values themselves, and the plans for future nutrients and food components are discussed. J Am Diet Assoc. 1998;98: 699–706 .
5,266 citations
TL;DR: In recognition of its generalized pleiotypic actions, sulfation factor was renamed somatomedin (mediator of the effects of somatotropin) and was included in the emerging classification of broad spectrum growth factors along with platelet derived growth factor, fibroblast growth factors, and epidermal growth factor.
Abstract: I. Introduction THE insulin-like growth factors were discovered on the basis of their ability to stimulate cartilage sulfation and to replace the “sulfation factor activity” of GH, as determined using an in vivo assay, in an in vitro test system (1). The biological significance of this finding was quickly expanded beyond the study of cartilage sulfation to include stimulation of DNA synthesis (2), proteoglycan synthesis (3), glycosaminoglycan synthesis (4), and protein synthesis (5). Most of these studies used tissue preparations such as isolated diaphragm, cartilage, or epididymal fat pads to study biologicalactivity. In recognition of its generalized pleiotypic actions, in the early 1970's sulfation factor was renamed somatomedin (mediator of the effects of somatotropin) and was included in the emerging classification of broad spectrum growth factors along with platelet derived growth factor, fibroblast growth factor, and epidermal growth factor (6). During the period in which the biological actions of ...
4,706 citations
"The role of iodine in human growth ..." refers background in this paper
...Approximately 95% of irculating IGF-1 is bound to insulin-like growth factor binding rotein (IGFBP)-3; binding prolongs the half-life of circulating GF-1 and may target IGF-I towards growth stimulation and way from glucose metabolism [94,96]....
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...Insulin-like growth factor (IGF)-1 is a growth factor that medites many of the effects of GH [94,95]....
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TL;DR: Undiagnosed hypothyroidism in pregnant women may adversely affect their fetuses; therefore, screening for thyroid deficiency during pregnancy may be warranted.
Abstract: Background When thyroid deficiency occurs simultaneously in a pregnant woman and her fetus, the child's neuropsychological development is adversely affected. Whether developmental problems occur when only the mother has hypothyroidism during pregnancy is not known. Methods In 1996 and 1997, we measured thyrotropin in stored serum samples collected from 25,216 pregnant women between January 1987 and March 1990. We then located 47 women with serum thyrotropin concentrations at or above the 99.7th percentile of the values for all the pregnant women, 15 women with values between the 98th and 99.6th percentiles, inclusive, in combination with low thyroxine levels, and 124 matched women with normal values. Their seven-to-nine-year-old children, none of whom had hypothyroidism as newborns, underwent 15 tests relating to intelligence, attention, language, reading ability, school performance, and visual–motor performance. Results The children of the 62 women with high serum thyrotropin concentrations performed sli...
2,197 citations
"The role of iodine in human growth ..." refers background in this paper
...However, maternal hyroid dysfunction in these studies was presumably not due to D, as they were done in the USA [39] and in the Netherlands 40]....
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...[39], he IQ scores of 7–9-year-old children of mothers with subclinial hypothyroidism during pregnancy (an increased TSH in the 2nd rimester) were 4 points lower compared to children from mothrs with normal thyroid function during pregnancy....
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Book•
01 Jan 2001
TL;DR: In this article, a review of the scientific literature regarding dietary micronutrients, recommendations have been formulated regarding vitamins A and K, iron, iodine, chromium, copper, manganese, molybdenum, zinc, and other potentially beneficial trace elements such as boron to determine the roles, if any, they play in health.
Abstract: This volume is the newest release in the authoritative series issued by the National Academy of Sciences on dietary reference intakes (DRIs). This series provides recommended intakes, such as Recommended Dietary Allowances (RDAs), for use in planning nutritionally adequate diets for individuals based on age and gender. In addition, a new reference intake, the Tolerable Upper Intake Level (UL), has also been established to assist an individual in knowing how much is "too much" of a nutrient. Based on the Institute of Medicine's review of the scientific literature regarding dietary micronutrients, recommendations have been formulated regarding vitamins A and K, iron, iodine, chromium, copper, manganese, molybdenum, zinc, and other potentially beneficial trace elements such as boron to determine the roles, if any, they play in health. The book also: * Reviews selected components of food that may influence the bioavailability of these compounds. * Develops estimates of dietary intake of these compounds that are compatible with good nutrition throughout the life span and that may decrease risk of chronic disease where data indicate they play a role. * Determines Tolerable Upper Intake levels for each nutrient reviewed where adequate scientific data are available in specific population subgroups. * Identifies research needed to improve knowledge of the role of these micronutrients in human health. This book will be important to professionals in nutrition research and education.
1,724 citations
TL;DR: The data considerably strengthen the contention that the synaptic changes exhibited in LTP are the basis for spatial memory.
Abstract: Although long-term potentiation (LTP) has been studied as the mechanism for hippocampus-dependent learning and memory, evidence for this hypothesis is still incomplete. The mice with a mutation in the alpha-calcium-calmodulin-dependent kinase II (alpha-CaMKII), a synaptic protein enriched in the hippocampus, are appropriate for addressing this issue because the hippocampus of these mice is deficient in LTP but maintains intact postsynaptic mechanisms. These mutant mice exhibit specific learning impairments, an indication that alpha-CaMKII has a prominent role in spatial learning, but that it is not essential for some types of non-spatial learning. The data considerably strengthen the contention that the synaptic changes exhibited in LTP are the basis for spatial memory.
1,341 citations