The Study
The TSH-Dependent Variation of the Essential Elements Iodine, Selenium and Zinc within Human Thyroid Tissues
This study looked at how much iodine, selenium, and zinc were in people's thyroid glands and compared that to their TSH hormone levels. It found that when TSH was higher or lower, the elements were sometimes different too — but it didn't prove that one causes the other. It's like noticing that people who eat more ice cream also get more sunburns — they're linked, but ice cream doesn't cause sunburn.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
This study looked at how much iodine, selenium, and zinc are in people's thyroid glands and found that when the thyroid is sick or working harder (high TSH), it tends to have less of these important minerals.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 535 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — even if overall nutrient levels are normal in the population, the thyroid may be locally deficient when it's diseased or overworked, which could affect how well it functions.
- 2In thyroid disease, zinc was much lower in chronic thyroiditis than in other conditions.
- 3Higher TSH levels were linked to lower iodine, selenium, and zinc in the thyroid.
- 4Iodine varied a lot between tiny thyroid sacs, but selenium and zinc were evenly spread.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of Trace Elements in Medicine and Biology
Year
1998
Authors
G. Bellisola, P. Brätter, G. Cinque, G. Francia, S. Galassini, D. Gawlik, V.E. Negretti De Brätter, L. Azzolina
Related Content
Claims (6)
Most cases of hypothyroidism occur because the immune system attacks the thyroid gland, and the thyroid naturally holds more selenium than most other tissues in the body.
In people with thyroid disease, the levels of iodine, selenium, and zinc in thyroid tissue are typically within the range seen in earlier studies, even though the general population may have slightly low levels of iodine and selenium.
In people with thyroid diseases, higher levels of TSH in the blood are linked to lower amounts of iodine, selenium, and zinc in the thyroid tissue, indicating that thyroid function may be related to the balance of these trace elements.
In the thyroid gland, iodine levels differ greatly from one follicle to another, while selenium and zinc levels remain relatively consistent across follicles, suggesting iodine is actively regulated in a variable way, whereas selenium and zinc are distributed more evenly.
Patients with chronic lymphocytic thyroiditis have lower levels of zinc in their thyroid tissue compared to patients with other thyroid conditions such as multinodular goiter, adenoma, or cancer.
In patients with mild deficiencies of iodine and selenium, the levels of these elements in thyroid tissue change in ways that relate to the amount of thyroid-stimulating hormone present, suggesting that nutrient levels and thyroid activity are linked in diseased tissue.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.