What Do Those Confusing Protein Terms Mean?

Submitted by Anonymous on Sun, 05/22/2011 - 05:13

Proteins

Like the first two members of the nutrition big 3, fats and carbohydrates, proteins have their own language. Here are some nutritional terms you should know:

Protein comes from the Greek word protos, meaning "first." These nutrients are the basic elements of living cells, of first importance. Like carbohydrates and fats, proteins contain carbon, hydrogen, and oxygen, but they contain one more element that sets them apart from the other two - nitrogen.

Amino acids are the molecules that make up the proteins. There are 20 different amino acids in the human body, but there are many possible combinations of these amino acids. think of it this way. Amino acids are like letters, and proteins are like words. There are many ways to put letters together to make words, and each word has a different function, a different place in the language. The protein you eat is broken down into individual amino acids in the digestive system, and then different cells take the ones they need and recombine these amino acids into the proteins that make up your body. Picture a Scrabble board full of words. Then imagine the tiles getting dumped, mixed up, and reassembled into new words.

Essential and non-essential describe the two kinds of amino acids. Of the 20 amino acids in the human protein "alphabet," thirteen are non-essential amino acids, meaning your body can make them; you don't have to eat them. Nine are essential amino acids, meaning your body can't make them; It's essential that you get them from foods.

COMPLETE AND INCOMPLETE PROTEINS
Getting the right kinds of protein is similar to shopping for clothes. Some clothing comes in complete sets. The jacket is sold with the skirt or pants and together they make a complete outfit. With other clothing you mix and match: jeans from one rack, a shirt from another, maybe a sweater from a different store across town. Proteins, too, come in complete sets or as incomplete parts that work together. A complete protein contains all nine of the essential amino acids; a protein missing one or more of these is an incomplete protein. Naturally, foods that come from species closest to humans (i.e., animal foods) contain complete proteins, since animal tissues have an amino acid composition similar to our own. Both grains and legumes contain significant amounts of protein, but these proteins do not contain all of the essential amino acids. Except for soybeans, plant proteins do not contain all the essential amino acids, so they are called incomplete proteins.

Another way to evaluate proteins is to consider the biological value (BV) of a protein, meaning not only how rich it is in essential amino acids, but also how well it can be digested by the intestines. Animal proteins are around 95 percent digestible and plant proteins range between 80 and 90 percent digestible.

Complimenting and combining proteins. While it may seem that animal proteins are better nutritionally, the differences in quality between animal and plant proteins are more theoretical interest than practical significance. People can grow just as well on plant proteins. (Plant-protein eaters may even be healthier, since they avoid the fat that comes with animal protein.) One plant food can supply the amino acids missing in another. Proteins from different kinds of plants complement each other and, in fact, many common and traditional foods are based on complementary proteins.

Don't be misled into thinking that you must eat meat twice a day or even once a day to get the protein you need. Even though plant proteins are not complete proteins, you can make up for what any one food lacks by eating a wide variety of plant and dairy foods. A hefty salad with a sprinkling of parmesan cheese and a topping of sunflower seeds is a healthy protein lunch.

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What Do Those Confusing Protein Terms Mean?

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