Posted on 27 Sep 2011 18:01
At present, there are about 100 elements known. The human body uses around 27 of these. The most abundant is oxygen, which makes up approximately 63% of the body's mass. Carbon comprises 18%, hydrogen 9%, and nitrogen 3%. These four are the key elements in body's most important molecules: water, proteins, lipids, carbohydrates, and nucleic acids.
Water accounts for about 55 to 65% of the body's weight. Proteins and lipids (fats) make up about 30 to 45% and minerals comprise another 5%. The remaining one percent is comprised of carbohydrates, nucleic acids, and various other organic molecules.
Except for water, each of the major molecules is made of smaller molecules. For instance, proteins are made up of amino acids and carbohydrates like the storage polymer glycogen are made of glucose molecules.
Approximate Amount of Body Mass Comprised of Each Element
- Oxygen: 63%
- Carbon: 18%
- Hydrogen: 9%
- Calcium: 1.5%
- Phosphorus: 1%
- Potassium: 0.4%
- Sulfur: 0.3%
- Chloride: 0.1%
Trace Elements in the Body
Trace elements such as silicon, boron, aluminum, iron, and selenium contribute less than 0.01% to the body's mass. Some other trace elements are: