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Does the human body contain minerals?

Category: Biology
Published: October 8, 2014

By: Christopher S. Baird, author of The Top 50 Science Questions with Surprising Answers and physics professor at West Texas A&M University

For the most part, the human body does not contain minerals. Scientifically speaking, a mineral is a naturally-occurring inorganic crystalline solid with a single chemical formula. Rocks are aggregates of minerals and organic materials. Except for in bones and teeth, the atoms and molecules making up a healthy body are not crystalline and are not solid. In this way, most of the molecules making up a human body fail to meet the definition of a mineral.

Confusion often arises because many health professionals, nutritionists, and biologists misuse the word "mineral". When they say "mineral" in the context of human nutrition, they really mean "dietary element". Scientifically, the phrase "trace element" should really be used instead of "trace mineral" when talking about rare atoms required by the human body. The words "element" and "mineral" do not mean the same thing. A chemical "element" is a material containing only one kind of atom. In some cases, elements can form minerals, but they don't have to. For example, hydrogen is an element, but it is not a mineral because it is neither crystalline nor a solid. In contrast, quartz is indeed a mineral, but it is not an element because it contains more than one kind of atom. A gold nugget found in the ground is both an element (because it contains only gold atoms) and a mineral (because it has a natural crystalline solid structure). The small subset of materials in the world that contain only one kind of atom and have the atoms naturally bonded into a solid crystalline lattice are called "native element minerals".

The Dictionary of Chemistry by N. Pradeep Sharma states under the entry titled mineral, "A naturally occurring substance that has a characteristic chemical composition and, in general, a crystalline structure is known as mineral." Under the entry titled element, this dictionary states, "A pure substance which cannot be broken down into anything simpler by chemical means...All elements have a unique number of protons in thier atoms." Listed below are some examples to illustrate the difference between these terms.

1. Materials that are elements, but not minerals

2. Materials that are minerals, but not elements

3. Materials that are both minerals and elements (native element minerals):

For example, table salt contains sodium atoms and chlorine atoms bound into a solid, ionic, cubic crystalline lattice. Naturally occurring salt is therefore a mineral. But as soon as you sprinkle salt on your tongue and begin to eat it, the salt dissolves in the water on your tongue. This means that the sodium and chlorine atoms break apart and float around in the water. You no longer have a mineral. You have elemental ions in solution. Your body then uses the dissolved elemental sodium ions to regulate fluid pressure levels and to send electrical signals along your nerves. In this way, you can eat minerals, but once you eat them, they aren't minerals anymore. Furthermore, you can get dietary elements from non-mineral sources. For example, you can get dietary sodium from milk, which is not a mineral. In fact, we get most of our dietary elements from non-mineral sources. The only mineral we really eat on a regular basis is table salt.

The one exception in a healthy human is bone mineral, such as in bones and teeth. Bone mineral is indeed an inorganic, crystalline, solid with a single chemical formula and therefore qualifies as a genuine mineral. The mineral in your bones is called hydroxyapatite and has the chemical formula Ca5(PO4)3(OH). Our bodies build bone mineral on the spot, so we don't have to swallow hydroxyapatite crystals. But we do have to eat food with enough of the right kinds of atoms to build bone mineral. Looking at the chemical formula, we see that our bodies can't build bone mineral unless we supply it with enough calcium, phosphorus, oxygen, and hydrogen. A typical person has almost unlimited access to hydrogen and oxygen atoms through the water he drinks and the air he breaths. In contrast, a person can only get enough calcium and phosphorus to build healthy bones if he eats and drinks foods containing these elements.

Minerals can also form in the human body as part of disease states such as in kidney stones.

Topics: atom, atoms, crystal, crystal lattice, element, lattice, mineral, native element minerals, nutrition, salt, solid