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- 1 Iodine suplementation
- 2 How can I tell if I’m iodine deficient before taking supplements?
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How can I tell if I’m iodine deficient before taking supplements?
You can't reliably tell from symptoms. The only real check is a urine iodine test, and even that is a population tool, not a personal verdict.
Urinary iodine concentration is the standard measure, with deficiency set below 100 µg/L for adults and below 150 µg/L in pregnancy [1][2]. But it reflects only recent intake, not your stored status [2]. One sample is noisy. A single low reading does not prove deficiency, and a single normal one does not rule it out.
Thyroglobulin is the better functional marker. In a UK pregnancy cohort, higher Tg tracked with lower iodine status, and Tg separated deficient from sufficient women better than TSH did [4]. In rural Niger, pregnant women had a median UIC of 69 µg/L while schoolchildren in the same households looked sufficient at 100.9 µg/L, so testing the wrong person gives the wrong answer [5].
| Marker | Deficiency cutoff | What it reflects |
|---|---|---|
| Urine iodine, adults | under 100 µg/L [1] | recent intake only |
| Urine iodine, pregnancy | under 150 µg/L [2] | recent intake only |
| Thyroglobulin | higher = worse [4] | thyroid strain over time |
| Goiter on exam | sign of long deficiency [3] | late, coarse |
Symptoms are not a test. Goiter shows up in long-standing deficiency, as in the Ethiopian women where 16% had one [3], but most deficiency is silent. This retrieval surfaced no study validating a symptom checklist for personal diagnosis.
My call: get a urine iodine and a thyroglobulin before supplementing, and skip the supplement if both are normal. Confidence: moderate.
Sources used 5
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Urinary iodine concentration: a biochemical parameter for assessing the iodine status
Urinary iodine concentration (UIC) is presented as a practical biomarker for assessing population iodine status, with WHO/ICCIDD thresholds distinguishing deficiency and excess and evidence that breast milk iodine concentration (BMIC) correlates with UIC to support public health…
DOI: 10.3329/mediscope.v5i2.37146 -
Iodine status and supplementation before, during, and after pregnancy
This review summarizes iodine requirements in preconception, pregnancy, and lactation, how population iodine status is assessed, the effects of maternal iodine deficiency and excess on pregnancy and child neurodevelopment, and the current evidence and recommendations regarding i…
DOI: 10.1016/j.beem.2020.101430 -
Lack of dietary sources of iodine and the prevalence of iodine deficiency in rural women from Sidama zone, southern Ethiopia
Widespread iodine deficiency among non-pregnant rural Ethiopian women in Sidama Zone, driven by complete lack of iodized salt and limited dietary iodine sources, is evidenced by a median urinary iodine concentration of 37.2 µg/L, 96.5% below 100 µg/L, and a 16% goiter prevalence…
DOI: 10.18697/ajfand.60.12735 -
Thyroglobulin as a Functional Biomarker of Iodine Status in a Cohort Study of Pregnant Women in the United Kingdom
This UK cohort study investigates whether serum thyroglobulin (Tg) is a functional biomarker of iodine status in pregnancy, finding higher Tg in iodine-deficient women, Tg showing a stronger relationship with iodine status than TSH, a gestational-week interaction that differs by…
DOI: 10.1089/thy.2016.0322 -
Urinary iodine concentration identifies pregnant women as iodine deficient yet school-aged children as iodine sufficient in rural Niger
Pregnant women in rural Niger show clear iodine deficiency by urinary iodine concentration, while school-aged children in the same households appear iodine sufficient, indicating that monitoring only children underestimates maternal iodine risk and that thyroglobulin may be a mo…
DOI: 10.1017/s1368980016003232