03 Calcium

Calcium plays a very important role with regards to many bodily functions. It helps build stronger bones and also helps with nerves and muscle contraction. Almost all calcium in the body is stored in the bones and teeth. However, in order for humans to absorb calcium, we need vitamin D. Without vitamin D, we can ingest as much calcium as we want, but we won't be able to use it!

In addition to making strong bones, calcium is also used to make cheese and cement, and to remove nonmetal from various metal mixes. Pure calcium is actually a metal and it sometimes reacts explosively with water and acids.

Dairy products are a great source of calcium, but so are orange juice, tofu, collard greens, white beans, almonds, bok choy, rhubarb, and broccoli. Calcium makes up the hard, outer structure of bones in the body, and gives them their strength. The inside of bones is spongy and full of holes — this makes them very light. Although most calcium in the body is found in the bones, it is also found in cartilage — the soft connective tissue between joints.

Calcium is also the reason doctors can take x-rays. The calcium on bones shows up bright white in x-rays.

Word List

ingest : take into the body

spongy : soft and flexibl

You Practice

I. Answer the following questions.

1) How do calcium and vitamin D work together?

2) What foods are a good source of calcium?

3) What is your favourite food that has calcium in it?

4) How can calcium help doctors?

5) What do you think might happen if we don't eat enough food that has calcium?

II. Word power—Use these words from the reading in sentences of your own.

1) spongy _______________________________________________

2) calcium ______________________________________________

3) ingest ________________________________________________

4) connective ____________________________________________

5) nonmetal _____________________________________________

III. True / False / Not Given—Write T if the sentence is true, F if the sentence is not true, or NG if there is no information about the sentence.

____ 1) Only dairy products supply calcium.

____ 2) Calcium is a mineral.

____ 3) It is a good idea to eat pure calcium.

____ 4) Without calcium, our bones would be very strong.

____ 5) Most calcium in the human body is found in cartilage.