Amino acids are organic compounds that combine to form proteins . When proteins are digested, amino acids are left. The human body requires a number of amino acids to grow and breakdown food.

Amino acids are classified into two groups:

• Essential amino acids cannot be made by the body and must be supplied by food. These include cysteine, lysine, and tryptophan . Sources of essential amino acids include milk, cheese, eggs, certain meats, vegetables, nuts, and grains.
• Nonessential amino acids are made by the body from the essential amino acids or normal breakdown of proteins. They include aspartic acid, glutamic acid, and glycine.

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