The NRC set the maximum tolerable level for horses at 40 mg Fˉ per kg of dietary dry matter (total dietary intake), but noted that level could decrease if horses’ drinking water exceeds 3 mg Fˉ/L. | Photo: iStock

Fluorine is a trace element most commonly found in nature as its less reactive form, fluoride (Fˉ). Although fluorite carvings from ancient times exist and it’s thought that artisans used fluorite combined with a strong acid for glass etching, there’s very limited information on Fˉ use in these times.

Scientists have long known that, in large quantities, fluorine is a toxic element and have been evaluating its toxic properties since the mid-1800s. In appropriate amounts, however, Fˉ can be is beneficial to bone and teeth health, increasing their crystallinity and hardness and decreases their overall solubility.

Consequently, some communities around the world with low water Fˉ content have chosen to add Fˉ to their public water supply, following recommendations and guidelines set forth by authorities such as the World Health Organization