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Iodine-Containing Springs: Non-Volcanic Rarity with Cholesterol Benefits

Published May 5, 2026·1min read

Iodine-containing springs hold iodide ions (I⁻) at 10 mg/kg or more, mainly found in non-volcanic geological strata. Clear at first, they turn yellow when left to stand. Drinking is indicated for dyslipidemia. Note: persons with hyperthyroidism should be cautious.

Iodine-Containing Springs: Non-Volcanic Rarity with Cholesterol Benefits
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Table of Contents
  1. What is an Iodine-Containing Spring?
  2. Indications for Drinking
  3. How to Bathe in an Iodine-Containing Spring

What is an Iodine-Containing Spring?

An iodine-containing spring holds iodide ions (I⁻) at 10 mg per kilogram of spring water. Unlike most hot springs, these emerge from non-volcanic geological strata (sedimentary layers), and notable examples are found in Chiba and Niigata prefectures.

Clear when fresh, they turn yellow to brownish when left standing as iodide oxidizes. They have a medicinal aroma reminiscent of iodine antiseptic solution, with a distinctive bitter taste.

Japan is one of the world's largest iodine producers; much of it is extracted from the iodine-rich brine (saline groundwater) found in these same geological formations.

Indications for Drinking

  • Dyslipidemia (high cholesterol)

How to Bathe in an Iodine-Containing Spring

  1. Yellow color indicates freshness — deeper color means more oxidation has occurred.
  2. Remove silver and brass jewelry before bathing — iodine can cause discoloration.
  3. If drinking, strictly follow the facility's posted daily limit.
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