Blog-5-13 by Felix Liao, DDS

Iodine Deficiency Hurts Mind-Body-Mouth

What All Mothers Need to Know About Childrens IQ and Dental Development

Question: What is the leading preventable cause of mental retardation?

Answer: Iodine Deficiency during pregnancy (1, 2)

Iodine deficiency is also linked to higher incidence of AHDH and lower IQ (3), and weak enamels and delayed eruption of teeth (4). Iodine is needed to make thyroid hormones to keep the body warm and all the cells working. The developing fetal brain is completely dependent on maternal thyroid in the first trimester (5). 

A woman low on iodine and thyroid risk having children with low intelligence, short stature, underdeveloped jaws, and dental problems. Oral manifestations of endocrine dysfunction often may be observed initially by the dentist (6), including but not limited to:
  • Mouth breathing, large swollen tongue, anterior open bite, small jaws (4) — which are also risk factors for sleep apnea later
  • Dry mouth, which can lead to susceptibility to cavities and gum disease
  • Pain:Low thyroid is almost a constant finding in Dental Distress Syndrome” (7)
Anterior open bite after braces
Anterior Open Bite without braces
Swollen tongue from low thyroid
Sign of Hertoghe for low thyroid: Outer 1/3 of eye brow missing

Common symptoms of low thyroid include:

* Fatigue, weight gain, headache, brain fog

* Thinning or missing outer third of the eye brow

* Hoarse voice, puffy face, constipation, PMS

* Cold hands & feet, thinning hair, fading memory

* Hoarse voice, swollen tongue

A mother with these symptoms during or prior to pregnancy may wish to have her children checked for dental signs of iodine deficiency. For more information, click on Iodine And Your Childs Brain Function And IQ by Dr. Joseph Mercola, which includes a lecture by endocrinologist Dr. Jorge Flechas, MD.

Tongue with tooth prints on its sides can mean low thyroid. No space between the tongue’s sides and mouth corners is a sign.
No tooth prints on side of tongue. “Space of one finger’s width between the tongue’s sides and mouth corners is a sign of adequate thyroid.” Jorge Flechas, MD

One gram of prevention beats a ton of cure. Here is what every woman needs to know about iodine deficiency:

  • Even mild iodine deficiency during pregnancy, which may be present in some women in the United States, may be associated with low intelligence in children (8)
  • Iodine requirements are increased 50% during pregnancy (9)
  • Severe iodine deficiency in the mother has been associated with miscarriages, stillbirth, preterm delivery, congenital abnormalities (8) and learning disabilities (3)
  • Tongue with tooth prints on its sides can mean low thyroid. No space between the tongues sides and mouth corners is a sign.No tooth prints on side of tongue. Space of one fingers width between the tongues sides and mouth corners is a sign of adequate thyroid.Jorge Flechas, MDLower IQ of 12-13.5 points are seen in iodine deficient populations, whereas Iodine supplementation before or during early pregnancy generally increases developmental scores in young children by 10-20% (9)

As part of a health care team, the dentist plays an important role in detecting thyroid abnormalities (10). Iodine and thyroid hormones require expert monitoring and balancing by medical professionals, and a knowledgeable dentist can make a positive difference in the total health of mothers and children.

  1. Dunn JT, J Pediatr Endocrinol Metab. 2001;14 Suppl 6:1469-73.
  2. Delange F, Thyroid. 1994 Spring;4(1):107-28.
  1. Vermiglio F, ADHD in Offsprings, J. Clinic. Endocr Metab, 2004, 89(2): 6054-60:
  1. Chandna S, Indian J Endocrinol Metab. 2011 July; 15(Suppl2): S113–S116.
  2. de Escobar GM, et al, Public Health Nutr. 2007 Dec;10(12A):1554-70.
  3. Ionescu O, and others, Ann Endocrinol (Paris). 2004 Oct;65(5):459-65.
  4. Fonders A , Dental Distress Syndrome Quantified, (1987) Basal Facts, 9(4), 141-167
  5. American Thyroid Association:
  1. Zimmerman MB, Paediatr Perinat Epidemiol. 2012 Jul;26 Suppl 1:108-17:
  2. Pinto A., Glick M., Management of patients with thyroid disease: oral health considerations, J Am Dent Assoc. 2002 Jul;133(7):849-58:
Skip to content