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What's Your Iodine Status?

September 27, 2021 | Dr. Linda J. Dobberstein, DC, Board Certified in Clinical Nutrition


Nearly 2 billion people across the globe are estimated to have inadequate iodine intake. Of this number, about 300 million are children. This trace mineral is well-known for its role with thyroid health but it also affects your whole body. Despite the implementation of iodized salt decades ago, many individuals still lack adequate iodine intake.


Iodine was discovered in 1809 by French scientists. By 1895, iodine was widely used as a universal remedy for nearly all human ills with extraordinary results. Historical treatment dosages ranged from a few milligrams (mg) to markedly higher doses. After World War II, iodine usage and its recorded medical history have been substantially silenced.


Intake Amounts


The US RDA for iodine in adult men and women is 150 microgram (mcg) per day. The RDA for women who are pregnant or breastfeeding is 220 – 290 mcg/day. The RDA for infants 0 – 12 months is 110-130 mcg. Children ages 1-13 years is 90 – 120 mcg. This dose is usually sufficient if iodine stores in your body are adequate.


World organizations recommend 1.0 - 1.8 mg of iodine daily for replenishing iodine stores. Higher iodine intake of 1 - 6 mg per day acts as an antioxidant. Individuals with iodine sensitivity or underlying thyroid disease should consult with their health care professional about iodine intake. Iodine excess may be a concern for those with autoimmune thyroid disorders. Too much and too little iodine intake affects health.


Pregnant and Breastfeeding Women


Studies measured dietary iodine in pregnant women in the United States, which showed this population group often lacks adequate iodine intake. Expectant women are considered a high-risk group for iodine deficiency.Prevalence of inadequate iodine intake in women of child-bearing age has actually increased in recent years.


Consequences of insufficient iodine intake during pregnancy affect the unborn child with potential life-long consequences. Risks associated with severe iodine deficiency include neuro-developmental deficits that affect physical and mental development. Iodine deficiency during pregnancy leads to lower intelligence, impaired mental function, stunted growth, delayed sexual maturation, as well as increased risk of stillborn or infant death.


Lab Tests


Lab tests for iodine status include urine and blood tests. Urinary iodine concentration assesses more immediate iodine intake. Urinary iodine concentration of 100-199 mcg/L in children and adults, 150-249 mcg/L in pregnant women, and greater than 100 mcg/L in breastfeeding women are considered adequate according to the World Health Organization.


The blood test for thyroglobulin reflects iodine nutrition over a period of months to years. Thyroglobulin is a thyroid protein that is a precursor to thyroid hormone. Thyroglobulin levels increase in response to an enlarged thyroid and with the development of a goiter from insufficient iodine intake.


Research suggests that blood tests of TSH and T4 concentrations do not adequately reflect low iodine status. Other research from a recent NHANES study showed that low iodine and iron levels were associated with increased levels of TSH and reduced free T3. Women were more affected than men. To avoid potential confusion and missed information, test urinary iodine concentration and thyroglobulin levels with TSH, T4, and T3 levels.