Potassium Iodide

Potassium iodide is an inorganic compound with the chemical formula KI. It consists of potassium and iodide ions and is a white crystalline salt that is highly soluble in water. The compound is identified by CAS Number 7681-11-0 and serves as a concentrated source of bioavailable iodine for human nutrition.

Potassium iodide is primarily used as a nutrient supplement in food applications, most commonly in iodized salt products. It is added at controlled levels (typically 20-100 micrograms per serving) to help prevent iodine deficiency in populations consuming the salt. Beyond food, potassium iodide is used in pharmaceutical applications, as a tracer in medical diagnostics, and in laboratory research. It is also employed in some industrial applications including photographic film and analytical chemistry.

Potassium iodide has an extensive history of safe use as a food additive and nutrient supplement. The FDA has reported zero adverse events associated with potassium iodide used as a food additive and zero recalls related to this substance. The compound is recognized as safe for its intended nutritional purpose when used at established levels in food fortification programs.

Iodine, the nutrient provided by potassium iodide, is an essential trace element required for thyroid hormone synthesis and normal metabolic function. Dietary intake recommendations vary by age and population, with the FDA establishing recommended daily allowances ranging from 90 to 150 micrograms for adults and children over age 4. The World Health Organization (WHO) supports iodine fortification of salt as an effective public health measure to prevent iodine deficiency disorders.

At supplemental levels used in food fortification, potassium iodide demonstrates excellent safety. Excessive iodine intake can theoretically cause iodine-induced hyperthyroidism in susceptible individuals, but this typically requires intake well above nutritional supplementation levels. Such effects are more associated with pharmaceutical doses rather than food fortification levels.

Potassium iodide is classified as a nutrient supplement rather than as a food additive requiring specific FDA GRAS (Generally Recognized as Safe) approval. It is approved and regulated by the FDA as a food fortification ingredient under 21 CFR 182.5375. The FDA permits its use in salt products and other foods at specified levels to prevent iodine deficiency.

International regulatory bodies including the European Food Safety Authority (EFSA) and the Joint FAO/WHO Expert Committee on Food Additives (JECFA) have also assessed potassium iodide as safe for use in food fortification programs at established levels. Many countries worldwide utilize potassium iodide in salt fortification as part of mandatory or voluntary nutrition programs.

Decades of epidemiological data support the safety and efficacy of potassium iodide in salt fortification programs. Research demonstrates that iodized salt programs have successfully eliminated iodine deficiency disorders in numerous populations. Studies monitoring long-term consumption of iodized salt containing potassium iodide show no adverse health effects at the fortification levels employed.

Public health research continues to document the effectiveness of potassium iodide fortification in preventing goiter, cretinism, and other iodine deficiency disorders. The WHO and UNICEF actively promote salt iodization with potassium iodide as a cost-effective intervention for populations at risk of iodine deficiency.