Salt

Go shopping in a supermarket and you will notice how many "reduced salt" products are for sale, purporting to be a healthier alternative. Many farmers face problems with rising salinity damaging their soils and water supply. Likewise, a number of Australian cities are building desalination plants to remove the salt from seawater, thus making it drinkable. With such negative publicity it's easy to forget that salt, or sodium chloride to be precise, is vital for complex organisms like humans.

A recent study comparing the preferences of ants for sugar or salt illustrates the necessity of salt in the diet of animals.