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THYROID FUNCTION

Arsenic

As — Element #33

also known as Arsenate, Arsenite, Monomethylarsonic acid (MMA), Dimethylarsinic acid (DMA)…

Arsenic is a metalloid classified as an ultratrace element with highly controversial and unconfirmed conditional essentiality. Animal studies suggest inorganic arsenic deprivation at extremely low levels may impair growth and reproduction, but no essential function has been identified in humans. Inorganic arsenic is simultaneously a well-established human carcinogen (Group 1, IARC) and a major global public health hazard through contaminated groundwater. Any potential nutritional role is dwarfed by its toxicological risk profile.

Animal deficiency studies (rats, hamsters, goats, chickens) on ultra-low arsenic diets show impaired growth, reproductive failure, and metabolic abnormalities — suggesting possible essentiality at sub-microgram levels
Organic arsenobetaine found in seafood is considered non-toxic and non-essential; it passes through the body largely unchanged
Arsenic trioxide (Trisenox) is an FDA-approved chemotherapy agent for acute promyelocytic leukemia — a specific pharmacological application, not nutritional
No confirmed essential function has been identified in humans at any dietary intake level

Active in As³⁺ (arsenite, inorganic — most toxic), As⁵⁺ (arsenate, inorganic), Arsenobetaine (organic — low toxicity).

No RDA established; no safe supplemental dose defined — arsenic is primarily approached from a toxicology standpoint

Inorganic arsenic is a Group 1 human carcinogen (IARC); chronic low-level exposure via drinking water is associated with bladder, lung, and skin cancers

The WHO guideline for arsenic in drinking water is 10 mcg/L; many regions worldwide exceed this from natural groundwater contamination

Acute arsenic poisoning causes severe gastroenteritis, cardiovascular collapse, encephalopathy, and death

Chronic arsenic exposure causes arsenicosis: keratosis, hyperpigmentation, peripheral neuropathy, and multi-organ damage

Rice and rice-based products contain higher inorganic arsenic than other grains due to paddy flooding; infant rice cereal has been a particular concern

NIH ODS — Arsenic · NCBI — IARC Monograph on Arsenic · WHO — Arsenic Fact Sheet · Britannica — Arsenic

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