The four main elements needed to build a living body

The 25 elements found in living bodies are not present in equal amounts. Just as a building is made mostly of bricks, cement, sand and water, most of a living body is built from just four elements:

Other elements essential to living things

Besides the four elements above, living things need several more. The body needs them only in very small amounts, but none of them can be replaced by another. If even one is missing, the organism cannot stay healthy.

• Sulphur (S) and Phosphorus (P)
• Sodium (Na) and Potassium (K)
• Calcium (Ca) and Magnesium (Mg)
• Iron (Fe) and Chlorine (Cl)