6New European recommendations on iodine intake The European Food Safety Authority (EFSA) has proposed an adequate intake (AI) level of µg for infants and children, 150 µg for adults and 200 µg for pregnant and lactating women.จากเดิม 250 µgAn AI is the average observed daily level of intake by a population group (or groups) of apparently healthy people that is assumed to be adequate.This Scientific Opinion is now open for public comment, and stakeholders can give input until February 26, 2014.
13One Major Advantage of this System The thyroid gland is capable of storing many weeks worth of thyroid hormone (coupled to thyroglobulin).If no iodine is available for this period, thyroid hormone secretion will be maintained.
15Actions of Thyroid Hormones Thyroid hormones are essential for normal growth of tissues, including the nervous system.Lack of thyroid hormone during development results in short stature and mental deficits (cretinism).Thyroid hormone stimulates basal metabolic rate.What are the specific actions of thyroid hormone on body systems?
16Actions of Thyroid Hormone Required for GH and prolactin production and secretionRequired for GH actionIncreases intestinal glucose reabsorption (glucose transporter)Increases mitochondrial oxidative phosphorylation (ATP production)Increases activity of adrenal medulla (sympathetic; glucose production)Induces enzyme synthesisResult: stimulation of growth of tissues and increased metabolic rate. Increased heat production (calorigenic effect)
17Effects of Thyroid Hormone on Nutrient Sources Effects on protein synthesis and degradation:increased protein synthesis at low thyroid hormone levels (low metabolic rate; growth)increased protein degradation at high thyroid hormone levels (high metabolic rate; energy)Effects on carbohydrates:low doses of thyroid hormone increase glycogen synthesis (low metabolic rate; storage of energy)high doses increase glycogen breakdown (high metabolic rate; glucose production)
19Recommendations for iodine intake (µg/day) by age or population group Age or population groupaU.S. Institute of MedicineAge or population groupcWorld Health OrganizationInfants 0–12 months bChildren 0-5 years90Children 1-8 years90>Children 6-12 years120Children 9-13 years120>Adults ≥14 years150Adults >12 yearsPregnancy220250Lactation290a Recommended Daily Allowance. b Adequate Intake. c Recommended Nutrient Intake.
20The spectrum of iodine deficiency disorders, IDD FetusMiscarriage Stillbirths Congenital anomalies Increased perinatal morbidity and mortality Endemic cretinismNeonateNeonatal goiter Neonatal hypothyroidism Endemic mental retardation Increased susceptibility of the thyroid gland to nuclear radiationChild and adolescentGoiter(Subclinical) hypothyroidism Impaired mental function Retarded physical developmen tIncreased susceptibility of the thyroid gland to nuclear radiationAdultGoiter with its complications Hypothyroidism Impaired mental function Spontaneous hyperthyroidism in the elderly Iodine-induced hyperthyroidism Increased susceptibility of the thyroid gland to nuclear radiation
32ผลกระทบจากการขาดไอโอดีนเมื่อตั้งครรภ์ J Clin Endocrinol Metab. 2013 May;98(5): doi: /jc Epub 2013 Apr 30.Mild iodine deficiency during pregnancy is associated with reduced educational outcomes in the offspring: 9-year follow-up of the gestational iodine cohort.Hynes KL, Otahal P, Hay I, Burgess JRCONCLUSIONS:This study provides preliminary evidence that even mild iodine deficiency during pregnancy can have long-term adverse impacts on fetal neurocognition that are not ameliorated by iodine sufficiency during childhood.ผลการขาดไอโอดีนแม้เพียงเล็กน้อยระหว่างตั้งครรภ์ มีผลระยะยาวต่อระดับสติปัญญาของเด็ก แม้ว่าเมื่อคลอดมาแล้วจะไม่ขาดไอโอดีนก็ตาม
33General Population (mg/L) Pregnant and lactating women (mg/L) WHO/UNICEFF/ICCIDD criteria for assessing population iodine status using population median urinary iodine concentrationIodine StatusGeneral Population (mg/L)Pregnant and lactating women (mg/L)School children≥6 years old (mg/L)Excessive*≥300≥500Above requirementsIodine SufficientMild Iodine Deficiency50-99<150Moderate Iodine Deficiency20-49<20-49Severe Iodine Deficiency<20*The term “excessive” means in excess of the amount required to prevent and control iodinedeficiency. Values in this table are sourced from WHO/UNICEF/ICCIDD (2007a)