It's The Element That Counts - Elemental Calcium

Elemental calcium is the 5th element in the periodic table and the third most abundant metal in the earth's crust. Ironically, calcium can never be found in nature as an element since it easily reacts with oxygen and water (2 atoms of hydrogen + 1 atom oxygen) to form compounds. What we find are actually calcium compounds, which are abundant in the form lime, chalk and gypsum. Elemental calcium combines with other elements, carbon for instance, to form calcium carbonate. Elemental calcium (the metallic calcium) was first isolated in 1808 by English scientist Sir Humphry Davy by electrolysis of lime and mercuric oxide mixture.

Uses of elemental calcium
In recent years, scientist and engineers obtain elemental calcium by separating calcium atoms in lime using aluminum atoms in high temperatures and low-pressure containers. In industries, calcium is used to process thorium, uranium, and zirconium.

Slaked lime, an inexpensive base material widely used in the chemical industry, is formed when heated calcium carbonate turns to quicklime (CaO) and then added to water. The calcium carbonate compound is used in other industries as base material from white paint, toothpaste, cleaning powder, and antacids.

Daily requirement of elemental calcium
Calcium phosphate comprises most of the material found in bones and teeth. This is formed when elemental calcium mixes with phosphate. The body extracts calcium from food sources and supplements by breaking the calcium compound to separate elemental calcium during digestion. The body absorbs elemental calcium, which is needed to maintain bone and teeth density. The amount of elemental calcium absorbed by the body depends on the fractional absorption of a calcium source.

For instance, the fractional absorption of calcium carbonate is 40%. A 1000mg tablet of calcium carbonate, hence, can provide 400mg of calcium for the body to use. Other examples of certain foods and corresponding fractional absorption: milk (32%), broccoli (53%), brussel sprouts (64%), Chinese cabbage (54%), tofu (31%), and turnip greens (52%).

Every age bracket has a certain amount of daily elemental calcium requirement. Children 1-10 years old need 500-700mg of calcium daily, adolescents and young adults need 1,300mg of elemental calcium, adults up to 50 years old are required to have 1000mg of elemental calcium every day, people age 51 and above as well as pregnant and lactating women need 1,200mg of elemental calcium each day.

Thus, it is important to eat a variety of calcium-rich sources because one source might not suffice to provide the daily requirement of elemental calcium.