What Are Minerals?

Lucy Bell-Young

by Lucy Bell-Young

6th October 2021

Minerals are micronutrients that are found in small amounts in dietary sources, particularly fruits and vegetables. They have a wide range of functions, acting as electrolytes, inorganic cofactors of enzymes, and as materials to support healthy bones and teeth, hormone synthesis, muscle contractions, and haemoglobin synthesis.

What Are Minerals Needed For?

Minerals are inorganic micronutrients needed by the human body for a wide range of purposes. They fall into two classifications: macrominerals and trace minerals. All organisms need minerals, but in varying amounts and types.

We need a range of minerals to function normally and maintain health, including calcium, iron, zinc, iodine, phosphorus, potassium, magnesium, sodium, chloride, copper, and fluoride. As we mentioned, these function as electrolytes and cofactors, as well as inorganic materials for the synthesis of biomolecules, and for building tissues like bones.

What Are Minerals in Food?

A wide variety of minerals are found in food, but many of these aren’t useful for human metabolic processes. Some are even potentially harmful when taken in excess amounts. For example, arsenic is toxic, but it naturally occurs in the environment, especially when certain pollutants seep into the soil. 

Because of this, arsenic is easily absorbed by green, leafy vegetables like lettuce, radishes, broccoli, Brussels sprouts, kale, and cabbage.

Top down view of various wooden bowls of fruit
Minerals are most commonly found in fruits and vegetables

Non-essential minerals

There are also trace amounts of non-essential minerals found in food that may have beneficial effects. These are classed as non-essential because they don’t cause any disruption in the normal functioning of the human body if they’re not present in the diet. 

Some examples of these are aluminium, boron, bromine, cadmium, chromium, fluoride, germanium, lithium, nickel, silicon, strontium, tin, and vanadium. While many of these trace minerals are toxic, they are tolerable in small amounts.

Non-essential minerals are typically contaminants from the environment and transferred to our food via soil, water, and air. For example, food might be contaminated while being grown on a farm. Some common sources of contaminants include fertilisers, herbicides, insecticides, and background pollution. Many non-essential minerals are part of the metabolic byproducts of plants and animals. These include nitrates and sulphates, which are byproducts of bacterial actions.

The essential minerals

Minerals from dietary sources have different functions and levels of importance. Those that are essential to humans are classified into two categories: macrominerals and the trace minerals. They differ in terms of proportions needed by the body:

  • Macrominerals: Macrominerals are the essential and needed in relatively large quantities. They have structural and physiological functions. The seven macrominerals phosphorus, magnesium, calcium, potassium, sodium, chloride, and sulphur. 
  • Trace minerals: These are only needed in small amounts. They mainly function as cofactors (meaning they help enzymes work as catalysts), and as components of biological molecules like haemoglobin. The trace minerals are iron, zinc, manganese, copper, cobalt, fluoride, iodine, and selenium.

Examples of Common Minerals

Unless closely monitored by a nutritional expert, few people have a perfectly balanced diet that includes all the essential macronutrients and micronutrients needed in precise proportions. The most common minerals are those that are virtually ubiquitous in our daily diet.

For example, table salt is in almost all the food we eat. Table salt provides sodium and chloride ions that are necessary for maintaining the osmotic pressure in the cells. These are also responsible for transmitting electrical signals to different parts of our body from the brain and vice versa.

Similarly, calcium and zinc are commonly found in milk and other dairy products. If you regularly drink milk, you’ll probably be getting the required daily allowance of calcium and zinc. Eggs are another example of daily sources of minerals, specifically phosphorus, iron, and selenium.

What Are the 7 Major Minerals?

The seven major minerals are the macronutrients, namely:

  1. Sodium
  2. Phosphorus
  3. Chloride
  4. Calcium
  5. Magnesium
  6. Potassium
  7. Sulphur

Deficiency in one or more of these can lead to serious health problems. For example, calcium deficiency can lead to osteoporosis, especially in old people.

Line-up of 12 essential minerals represented by colour balls with element name

What Are Minerals Used For in the Body?

As we’ve mentioned, minerals have various functions, behaving as electrolytes, cofactors, and as structural materials for bones. Here are some examples of how they are used in the body:

  • Electrolytes: Electrolytes maintain the osmotic pressure in the cells that facilitate the cellular transport of fluids and materials. In fact, muscles wouldn’t be able to contract without electrolytes. The heart muscles, in particular, need a constant supply of electrolytes in order to beat. The brain also needs electrolytes to send signals to different types of muscles, including the internal organs. Nerve impulses from the brain and vice-versa would not be able to travel without electrolytes, and the brain itself would not function. 
  • Inorganic cofactors: Many enzymatic actions would not occur without the help of cofactors. Many cofactors are minerals in the form of ions. They mainly act as catalysts that facilitate biochemical reactions. One important example of a mineral cofactor is zinc, which is found in DNA polymerase. This enzyme is crucial in the synthesis of DNA molecules.
  • Bone and teeth materials: Around 99% of the calcium in our bodies is stored in our bones. The bone composition can be categorised into interdependent groups of chemicals that form the connective tissue: the mineral phase or hydroxyapatite (a form of calcium apatite), the organic phase (collagen type I), non collagenous proteins, other components, and water. Similarly, the teeth are also a repository of calcium.
  • Haemoglobin synthesis: Blood would not be useful as a carrier of oxygen without haemoglobin. This is an oxygen-transport metalloprotein that contains iron. Although the metalloprotein molecule is large and complex, it only contains one iron in the centre. People who don’t have enough iron can become anaemic as functioning haemoglobin molecules become scarce.


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