Nutrition Science and Everyday Application - beta v 0.1

308 ALICE CALLAHAN, PHD, HEATHER LEONARD, MED, RDN, AND TAMBERLY POWELL, MS, RDN
amino acid structures or names, but you should appreciate the diversity of amino acids and
understand that it is the side chain that makes each different.
Figure 6.2. Amino acids have different structures and chemical properties, determined by their
side chains.
ESSENTIAL AND NONESSENTIAL AMINO ACIDS
We also classify amino acids based on their nutritional aspects (Table 6.1 “Essential and
Nonessential Amino Acids”):
• Nonessential amino acids are not required in the diet, because the body can
synthesize them. They’re still vital to protein synthesis, and they’re still present in
food, but because the body can make them, we don’t have to worry about
nutritional requirements. There are 11 nonessential amino acids.
• Essential amino acids can’t be synthesized by the body in sufficient amounts, so
they must be obtained in the diet. There are 9 essential amino acids.