Importance of Iron in Diet

The best-known function of iron is to be part of the proteins hemoglobin and
myoglobin, which participate in oxygen transport.
1 In these proteins, the iron is not
inserted directly into the amino acid structure of the proteins, but rather is inserted
into chemical structures known as heme rings, which are inserted into the protein’s
amino acid backbone.
Iron also functions in enzymes that are iron–sulfur enzymes
(iron is chelated by sulfur amino acids). Iron also is part of structures known as
cytochromes, which are part of the electron transport chain of aerobic energy release,
and are part of a family of enzymes called cytochrome P-450 dependent enzymes.

The P-450 enzymes are involved in processes such as drug metabolism and steroid
hormone synthesis.
Iron affects aerobic energy metabolism in at least three ways:

1. Oxygen transport to cells (needed for the electron transport chain)
2. The iron enzyme aconitase in the Krebs Cycle
3. Cytochromes and iron–sulfur proteins in the electron transport chain
Iron enzymes participate in an assortment of other biological processes including
synthesis of neurotransmitters, peroxide conversions, purine metabolism, fatty acid
synthesis, DNA synthesis, and nitric oxide production.

Iron function also impacts
the immune system. The exact molecular mechanisms for this last connection are
hard to identify, since many iron functions could theoretically affect immune function.
For example, iron can affect DNA synthesis, which can affect cell multiplication,
which can affect immune responses.