Why the body needs raw materials every day

The human body is active at every moment — even when nothing is visible from the outside. Millions of cells renew themselves continuously, and at the same time every cell produces energy from food. Both processes run without conscious control and depend on a multitude of biochemical reactions.

For two of these reaction pathways — energy metabolism and cell division — certain minerals are of documented importance. The European Food Safety Authority (EFSA) has published scientific opinions on iron and magnesium, on the basis of which the European Commission has authorised the corresponding health claims.

In what follows, the two minerals are examined separately — with regard to their respective function in energy metabolism and cell division.

Two processes, one shared biochemical framework

At first glance, energy metabolism and cell division look like two separate fields. At the cellular level, however, they share a common infrastructure of enzymes, cofactors and transport molecules, in which iron and magnesium act at different levels.

Iron as a cofactor of mitochondrial enzymes

In the mitochondria, the power plants of the cell, iron is a component of heme and iron-sulfur clusters, which are needed to transport electrons in the respiratory chain. Cytochromes — iron-containing proteins — transfer the electrons from one complex to the next, until ATP is finally produced as a usable form of energy. If this electron transport is interrupted, the cell can produce energy only to a limited extent.

Magnesium and the binding of ATP

ATP, the molecule that carries energy within the cell, exists biologically almost exclusively as a magnesium-ATP complex. Magnesium neutralises the negative charge of the phosphate groups of ATP, making the molecule accessible to the enzymes that process it in glycolysis and the Krebs cycle. Without sufficient magnesium, the enzymatic processing of ATP slows measurably.

Cell division as a process of continuous renewal

Cell division allows the body to replace damaged or worn-out cells continuously. Before each division, all of a cell's DNA must be duplicated — a process involving various enzymes and their cofactors. Iron in particular is a component of ribonucleotide reductase, an enzyme that supplies the building blocks of new DNA strands. Magnesium, for its part, takes part in the activity of DNA polymerase, which copies the genetic information.