From the Guidelines
Low iodine levels should be addressed promptly to prevent severe health consequences, including goiter, hypothyroidism, and impaired brain development in children, by increasing dietary iodine intake or taking supplements, as recommended by the recent espen micronutrient guideline 1. To manage low iodine levels, it is essential to understand the daily requirements, which are 150 micrograms for adults, 220 mcg for pregnant women, and 290 mcg for breastfeeding women. The most effective ways to boost iodine intake include:
- Using iodized salt, with 1/4 teaspoon providing about 71 mcg of iodine
- Taking potassium iodide supplements, typically in the range of 150-1000 mcg daily
- Consuming good dietary sources such as:
- Seafood, especially cod, which provides about 99 mcg per 3-ounce serving
- Dairy products
- Eggs
- Seaweed, particularly kelp Symptoms of iodine deficiency can be non-specific and include fatigue, feeling cold, dry skin, hair loss, and trouble concentrating. However, severe deficiency can lead to more serious conditions like goiter and hypothyroidism, as iodine is crucial for thyroid hormone production, which regulates metabolism, growth, and development 1. It is critical to note that iodine deficiency during pregnancy and breastfeeding can have adverse effects on the development of the child, including impaired brain development, neurocognitive function, and reduced IQ 1. Therefore, if symptoms persist despite dietary changes, it is advisable to consult a healthcare provider who may order blood tests to check thyroid function and recommend appropriate treatment.
From the FDA Drug Label
SIDE EFFECTS: ... Taking iodide, in rare cases, may cause overactivity of the thyroid gland, underactivity of the thyroid gland, or enlargement of the thyroid gland (goiter). The FDA drug label does not answer the question.
From the Research
Low Iodine Levels: Effects and Recommendations
- Low iodine levels can lead to impaired thyroid function, including hypothyroidism and hyperthyroidism 2, 3.
- The recommended daily intake of iodide is 150 μg for adolescents and adults, and 250 μg for pregnancy and lactation 2.
- Iodine deficiency during pregnancy can lead to impaired child neurodevelopment, and supplements containing 150 μg/day are recommended for pregnant and lactating women 4.
- A study found that 24% of prenatal multivitamin doses sold did not contain iodine, highlighting the need for more effort to ensure adequate iodine content in prenatal vitamins 4.
- Iodine nutrition and timing of iodine supplement initiation are associated with thyroid function in pregnant and postpartum women, with lower iodine availability during pregnancy and postpartum associated with lower TSH and higher fT3 and fT4 concentrations 5.
- Excess iodine intake can also have negative effects on thyroid function, including precipitating hyperthyroidism, hypothyroidism, goiter, and/or thyroid autoimmunity, particularly in individuals with preexisting thyroid disease or those previously exposed to iodine deficiency 6.
Iodine Intake and Thyroid Function
- Increased iodine intake in an iodine-deficient population is associated with a small increase in the prevalence of subclinical hypothyroidism and thyroid autoimmunity 3.
- The use of an iodine-containing supplement that is initiated prepregnancy and continued through pregnancy is associated with lower TSH and higher fT3 and fT4 concentrations, suggesting improved thyroid function 5.
- The median urinary iodine concentration (UIC) of a population reflects the total iodine intake from all sources and can accurately identify populations with excessive iodine intakes 6.
Recommendations for Iodine Intake
- Optimization of population iodine intake is an important component of preventive health care to reduce the prevalence of thyroid disorders 3.
- Iodine supplements should be taken as recommended, with a daily intake of 150 μg for adolescents and adults, and 250 μg for pregnancy and lactation 2, 4.
- Prenatal vitamins should contain adequate amounts of iodine to support thyroid function during pregnancy and lactation 4.