2 Minerals and fluids
2.1 Introduction to minerals and why we need them
Both vitamins and minerals are essential in the diet in small quantities and so they are often grouped together as micronutrients.
Which items in the diet are classified as macronutrients?
The macronutrients are proteins, fats and carbohydrates.
Minerals, also called mineral elements, are those elements other than carbon, hydrogen, oxygen and nitrogen, that are found in the body. These minerals are derived from the breakdown of the rocks of the Earth's crust which are then dissolved in water. So in a particular area, the minerals present in the local water depend on the underlying geology. Plants take up the water through their roots and, if those plants are used as food for people or animals, then the minerals enter their bodies. Animals are able to concentrate minerals in their tissues, so human foods of animal origin often contain a higher concentration than food obtained from plants. Minerals are also taken in through drinks. Minerals are needed in only small quantities in the diet, though some of them accumulate to a significant degree; for example, there is around 1 kg of calcium in the average human body. For most minerals, it is possible to identify their roles in the body, although some have, as yet, no known function.