Because pure water has no nutrients in it it is simply water.

I don't know. I would have passed this one by, but on second thought it's actually rather interesting. I suppose that if water were not so ubiquitous, but were present in our foods and body at the same level as other nutrients, it would actually be considered as another nutrient. It is unusual in that it is more stable than other nutrients and is a smaller molecule than others. However it is not so stable that it is not converted to new molecules by the body, as are many nutrients. In hydrolysis reactions, for example, the addition of the hydrogens and oxygen atoms from water to another molecule are part of the chemical reaction breaking down into two shorter molecules. The most common nutrients like carbohydrates, fats, and proteins are organic, carbon based molecules. Iron and calcium, however, are nonorganic molecules, like water. However, these minerals are considered nutrients. While most nutrients are used to make structural components of the cells or as reactants in chemical reactions and energy metabolism, water's most common function is as a solvent and environment in which these necessary chemical reactions can take place, and water can dissolve and transport necessary molecules. I suppose it is just by this subtle distinction, by convention, and by it's ubiquitous nature that water is not considered a nutrient. Oxygen (O2) is a simpler molecule, but actually heavier than water. Should we be considering that as a nutrient also? Quoted from American Heritage Dictionary: Nutrient: Something that nourishes; especially, a nouishing ingredient in a food. Having nutritive value, as certain body fluids. Nutritive: Promoting nutrition; nourishing. Nourish: To provide with food or other substances necessary for life and growth. I don't see this excluding water.

Because it has no nutritional value. It is a staple in every persons diet, without a doubt, but without nutritional value it cannot be a nutrient.

because water has no nutritional value. If given nothing but water to sustain yourself on you would perish. although water..or fluids are necessary for survival you cannot survive on water. Most foods and fruit contain fluids vital to survive as well as nutrient..the same cannot be said for water.

Good question. Depending on the purity of the water, could it be considered since minerals are nutrients. What is the medical definition of nutrient? My understanding is that it is anything that is needed to sustain life. And since water is needed, could it not me a nutrient? Your making me think!

Perhaps because it is a liquid. Most consider nutrients solids or liquids containing a dissolved form.