What is proten needed for?

Answer 1

Protein is essential for humans...that means that we can't do without

it in our food and in our bodies, in part because of the nitrogen it

contains (the major source of nitrogen for the body) and in part because

of the particular building blocks that make up protein. Protein is made

up of twenty different building blocks, called amino acids, arranged in

thousands and thousands of different ways. Every cell in the human body

contains protein as part of its structure (cell membrane and other

structures). It also serves to build strong structures in the body, as a

whole (bones, muscles, tendons, and ligaments); it makes up the compounds

that your body used to make the biochemical reactions occur in your body,

called enzymes; it is found in your blood as parts of the red blood cells

(hemoglobin) and as carriers for other materials (transport proteins);

and it is part of the immune system (antibodies) that helps protect your

body from foreign invaders, such as bacteria, viruses, and toxic

substances.

Some proteins help keep the fluid in your body where it should be,

such as the proteins in your blood. Some proteins in your blood and other

tissues help keep the acid-base balance in your body in ranges that allow

you to stay alive. This last function is kind of interesting. The

structure of proteins allows them to act as either acid or base...and they

can break apart in the body to help neutralize too much base or acid,

especially in the blood stream.

There are some hormones that are built up of proteins; hormones are

very complicated compounds made in one organ and then moved somewhere else

in the body to have their effect. For example, insulin, a hormone made in

the pancreas and important for keeping the glucose level in your blood

stream at a safe and healthful level, is actually a protein. It helps take

glucose in the blood stream into tissues where it can be used as energy or

be stored away for future use.

Lastly, speaking about energy, your body can use the proteins in your

food (from both plant- and animal-based foods) for energy...you get about

4 kilocalories/gram from protein. However, your body 'prefers' to use a

mixture of carbohydrate and fat for energy...not a lot of protein. Under

certain circumstances (starvation, a reducing diet, illness), your body

will use protein for energy, when the supply of the other two nutrients

gets low or is not available. This limitation on the use of protein is

because protein (and the amino acids that make up protein) are better used

for the other purposes that I have mentioned above.

As I reread what I have written, it sounds very much like part of the

lecture that I do on 'protein' for my introductory nutrition students,

here at the University of Hawai`i/Manoa. In fact just to make sure that I

didn't forget anything, I used the textbook (Contemporary Nutrition,

Wardlaw, 5th edition)to help me with the answer. To recap, protein is

needed in the human body for 6-7 main reasons: part of body structures

(from cell to organ to system), maintain fluid and acid-base balance,

makes up some hormones and all enzymes, important for the immune system,

and a sometime source of energy.

One last comment, from the nutrition scientist in me. We, in the US,

probably get plenty of protein in our food. In fact, most of us eat about

2-3 times what our body actually needs. The body just breaks apart the

extra protein and stores away the byproducts or uses them for energy.

Most of our protein in the US comes from animal food (meat, poultry, fish,

and animal products, like eggs and milk). The rest comes from plants

(grains, seeds, and some vegetables). Some nutritionists, myself included,

think that the proportions of where our protein comes from should be

reversed, for a number of reasons (health, economics, environment)...that

is, we should get less of our protein from animal foods and more from

plant foods.

Answer 2

Proteins (Amino Acids) are important for growth mostly:)

Answer 3

Protein is needed to repair damage to muscle tissue faster, which would increase the amount of time one could exercise in a given amount of time.