Iodine

Source: Autism Dietitian Instagram

What is Iodine?

• Iodine is an element (and trace mineral) that can be found in food and is available as a dietary supplement. Iodine usually occurs as a salt, so it is typically known as iodide. 

• It is absorbed almost completely in the stomach and the duodenum (the upper small intestine).

• Iodine is important for thyroid health!

  • Iodine is a critical element needed for the production of thyroxine (T4) and triiodothyronine (T3), which are thyroid hormones. These hormones regulate many processes in the body, especially reactions that are critical for metabolic activity. 

  • In humans, the thyroid gland is regulated by thyroid-stimulating hormone (TSH). This process helps keep the body in a neutral state instead of having hypo- or hyperthyroidism. When there is not enough TSH, hormone levels stay high, which can lead to goiter. 

  • Goiter is the enlargement of the thyroid gland. These thyroid hormones are also necessary for normal development of the skeletal and nervous system in fetuses and infants, as well as immune function in children and adults. [1]

Sources of Iodine

• Iodized Salt 

• Seaweed 

• Cod 

• Yogurt 

• Bread  

• Fruit cocktail 

• Shrimp 

• Milk

• Eggs

• Cheese

• Apple Juice

Recommended Intake

These recommendations are based on the Recommended Dietary Allowance (RDA), which is the average daily level of intake sufficient to meet the nutrient recommendations of nearly all (97-98%) of healthy individuals.

Males and Females 

• 1-3 years: 90 mcg/day 

• 4-8 years: 90 mcg/day 

• 9-13 years: 120 mcg/day 

• 14-18 years: 150 mcg/ day 

• 19-50 years: 150 mcg/day 

• 51+ years: 150 mcg/day 

Deficiency

Common Symptoms of Iodine Deficiency Include: 

• Goiter

• Unexpected weight gain 

• Fatigue and weakness

• Memory issues

• Neurodevelopmental issues (infants and children) 

Individuals at Risk for Iodine Deficiency Include: 

• Those on a dairy-free diet may be at increased risk

• Children who are selective eaters

• People living in areas with iodine-deficient soil

• People who eat goitrogens 

  • Ex. soy, cassava, cabbage, broccoli, cauliflower

• People who don’t use iodized salt 

• Pregnant women 

  • Higher recommendations for intake but typically not met

Toxicity

Upper limits of iodine

• 1-3 years: 200 mcg/day 

• 4-8 years: 300 mcg/day 

• 9-13 years: 600 mcg/day 

• 14-18 years: 900 mcg/ day 

• 19-50 years: 1100  mcg/day 

• 51+ years: 1100 mcg/day  

Symptoms of Iodine Toxicity

• Goiter (mass on external throat area) 

• Burning of mouth, throat, and stomach

• Fever

• Abdominal pain 

• Vomiting

• Weak pulse

• Coma

Supplements

For dietary supplements, potassium iodide or sodium iodide are the most commonly seen. However, potassium iodide is better absorbed in humans.

Examples

• Iodine is present in iodized salt

• Iodine can be found in most multivitamins

• Iodine can also be found in individual supplements like Mary Ruth’s Iodine Drops
  

Note: All supplements are linked to Amazon for convenience, however, buying supplements on Amazon does not guarantee quality, as there are many “unverified resellers” selling nutrition supplements. To buy supplements that are verified to be sent directly to the consumer, you can create an account on the Autism Dietitian FullScript and search for the respective supplement under “Catalog”.

DISCLAIMER: Before starting any supplement or medication, always consult with your healthcare provider to ensure it is a good fit for your child. Dosage can vary based on age, weight, gender, and current diet.

Iodine & Autism in the Research

• One study revealed children with ASD have lower hair levels of essential and toxic trace elements including iodine, copper, and beryllium.  While another study showed  lower urinary iodine in boys with autism. [2][3]

• There is not enough evidence to support an association of mild-to-moderate iodine deficiency during pregnancy to ASD or ADHD. [4]

• Children with ASD had a higher risk of not consuming enough iodine than their typically developing peers. [5]

---

• References

  [1] Iodine Fact Sheet for Consumers. Nih.gov. Accessed February 8, 2021. https://ods.od.nih.gov/factsheets/Iodine-Consumer/ 

  [2]  Skalny AV, Simashkova NV, Klyushnik TP, et al. Analysis of Hair Trace Elements in Children with Autism Spectrum Disorders and Communication Disorders. Biol Trace Elem Res. 2017;177(2):215-223. doi:10.1007/s12011-016-0878-x

  [3]Błażewicz A, Makarewicz A, Korona-Glowniak I, Dolliver W, Kocjan R. Iodine in autism spectrum disorders. J Trace Elem Med Biol. 2016;34:32-37. doi:10.1016/j.jtemb.2015.12.002 

  [4]Levie D, Bath SC, Guxens M, et al. Maternal Iodine Status During Pregnancy Is Not Consistently Associated with Attention-Deficit Hyperactivity Disorder or Autistic Traits in Children. J Nutr. 2020;150(6):1516-1528. doi:10.1093/jn/nxaa051 

  [5]Marí-Bauset S, Llopis-González A, Zazpe I, Marí-Sanchis A, Morales Suárez-Varela M. Comparison of nutritional status between children with autism spectrum disorder and typically developing children in the Mediterranean Region (Valencia, Spain). Autism. 2017;21(3):310-322. doi:10.1177/1362361316636976

Authors

 Sheila Nguyen, Dietetic Intern

Suzy Morris, Dietetic Intern

Brittyn Coleman, MS, RDN/LD, CLT