Which nutrient is often injected into drinking water by treatment plants?

Fluoride is commonly injected into drinking water by treatment plants as part of a public health initiative aimed at reducing dental caries in the population. This practice, known as water fluoridation, has been endorsed by numerous health organizations because it helps strengthen tooth enamel and prevent cavities, particularly in children.

Fluoride works by being incorporated into the structures of developing teeth, making them more resistant to the acid produced by bacteria in the mouth. This preventive measure has been shown to significantly reduce the incidence of tooth decay in communities that fluoridate their water supply.

While substances like chlorine are used to disinfect water and ensure it is safe from pathogens, and sodium and calcium may be present in various forms in water supplies, they do not serve the same preventative health purpose that fluoride does in terms of dental health.