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Apr 23, 2010

Why does our body need proteins?

Protein can be found almost anywhere in the body, it is used to make cells. It is the main component of muscles, organs, and glands. Every living cell and all body fluids, except bile and urine, contain protein.

After foods have entered the body they are digested, and the amino acids become free, to be used by our bodies to make the necessary proteins. These are required for growth and development; for making new cell substances such as protoplasm, but also for making antibodies, enzymes, hormones, etc. Proteins serve also as an energy source.

What are the best sources of proteins?

If a protein in a food provides us with the essential amino acids, it is called a complete protein. If it does not supply all the essential amino acids, it is called an incomplete protein.

All meat and other animal products are sources of complete proteins. These products include beef, lamb, pork, poultry, fish, shellfish, eggs (the best source of complete proteins), milk, and milk products.

Protein in foods such as grains, fruits, and vegetables are considered incomplete proteins. Plant proteins can be combined to include all of the essential amino acids and form a complete protein. Examples of such combinations are rice and beans, and corn and beans.

What happens if protein intake is too high?

An ideal intake of protein is 0.8 grams per kilogram of body weight. Lack of proteins will lead to a weak body, which is unable to fight against diseases. Excess protein is defined as more than 1.6 grams per kilogram of body weight. A protein deficient diet may be better tolerated than a protein excess diet; too much protein in the diet is not healthy. The extra protein contains nitrogen, which is changed in the liver into a waste substance called urea. The kidneys need to get rid of this waste by excreting it in the urine. Too much protein can thus put a stress on the liver and kidneys.