Inorganic nutrients are chemical elements, compounds, and other substances necessary to sustain life processes — breathing, moving, eating, drinking, reproducing — that are not chemically carbon-based. Typically taken in in mineral form and in small or trace amounts, these nutrients are critical to a wide variety of basic life functions. As far as human nutrition is concerned, the following are considered essential: calcium, chloride, copper, fluorine, iodine, iron, magnesium, manganese, molybdenum, phosphate, potassium, selenium, sodium, sulfate, water, and zinc. A deficiency in one or more impairs bodily functions and generally results in very specific symptoms that, if deficiencies continue, can eventually result in death.
Nutrients change forms, transitioning between organic and inorganic forms in natural cycles and along natural pathways, before and after being absorbed and used by plants and animals. There are significant differences between inorganic and organic nutrients, but distinguishing between the two types is ultimately of limited value. For example, the inorganic forms of nutrients essential to plant life — principally nitrogen, phosphorous, and sulfur — can be readily absorbed and used by plants. Their organic counterparts, on the other hand, have to be broken down into simpler forms before the nutrients they hold can be absorbed. Whether organic or inorganic, both contain nutrients that life forms have evolved to absorb and use to sustain themselves.
Inorganic nutrients can be either essential or non-essential. The difference between the two is that that humans and other forms of life can produce non-essential nutrients themselves. Essential nutrients, on the other hand, have to be obtained and taken in from external sources, such as soil, food, water, or mineral supplements. There are 40 different types of essential nutrients are recognized, and they are divided into six groups: carbohydrates, proteins, fats, vitamins, minerals, and water.
What is an essential inorganic nutrient for one form of life may not be for another. For example, boron is an important mineral required in trace amounts that is considered essential for vascular plants and algae, but it is not considered essential for animal life, including human life. In contrast, iodine is essential for humans and other complex forms of animal life in that it is necessary for the production of the thyroxine group of thyroid hormones, which are involved in controlling the rate of metabolic processes in the body, as well playing a role in processes having to do with physical development.