Biological value (BV) Are All Protein Sources The Same

Proteins are part of every cell, tissue, and organ in our bodies. These body proteins are constantly being broken down and replaced. The protein in the foods we eat is digested into amino acids that are later used to replace these proteins in our bodies.

Protein is found in the following foods:

• meats, poultry, and fish
• legumes (dry beans and peas)
• tofu
• eggs
• nuts and seeds
• milk and milk products
• grains, some vegetables, and some fruits (provide only small amounts of protein relative to other sources)

As we mentioned, most adults in the United States get more than enough protein to meet their needs. It's rare for someone who is healthy and eating a varied diet to not get enough protein.

What are the types of protein?

Proteins are made up of amino acids. Think of amino acids as the building blocks. There are 20 different amino acids that join together to make all types of protein. Some of these amino acids can't be made by our bodies, so these are known as essential amino acids. It's essential that our diet provide these. 

In the diet, protein sources are labeled according to how many of the essential amino acids they provide:

•  A complete protein source is one that provides all of the essential amino acids. You may also hear these sources called high quality proteins. Animal-based foods; for example, meat, poultry, fish, milk, eggs, and cheese are considered complete protein sources.

• An incomplete protein source is one that is low in one or more of the essential amino acids.Complementary proteins are two or more incomplete protein sources that together provide adequate amounts of all the essential amino acids.

For example, rice contains low amounts of certain essential amino acids; however, these same essential amino acids are found in greater amounts in dry beans. Similarly, dry beans contain lower amounts of other essential amino acids that can be found in larger amounts in rice. Together, these two foods can provide adequate amounts of all the essential amino acids the body needs.

Are all proteins the same? No.  Protein values vary according to the quality of the protein.  The quality of proteins  can be measured in two ways. The most common measure is the Biological Value (BV).  The BV of certain proteins is calculated by measuring the percentage of protein consumed and absorbed versus how much of it is excreted as waste.  This gives an indication of how much of the protein that is consumed actually remains within the body to promote protein synthesis Protein synthesis means how much protein the body will actually use.

The second measure of protein quality is the protein-digestibility amino acid score (PCDAAS).  The PCDAAS method is based on human amino acid requirements.  Many health officials believe that this is the method to follow.  A PCDAAS of 1.00 or 100% is good quality.  Any lower and the protein must be combined with another source that may contain the sufficient amino acids to bring its score up. Protein sources that have less than 1.00 or 100% typically come from plant sources. 

Nutrition Strategy:  The biological value and/or PCDAAS of proteins are critical factors in absorption and retention in your body.  The following is a chart for the BV and PCDAAS of selected proteins:

BV AND PCDAAS OF SELECTED PROTEINS
	BV	PCDAAS
Whey Protein Isolates	159	1.0
Whey Protein Concentrate	104	1.0
Whole Egg	100	1.0
Milk	91	1.0
Egg White	88	1.0
Cottage Cheese	84	1.0
Tuna	83	-
Fish	82	-
Beef	80	0.9
Chicken	79	-
Soy	74	0.9
Casein	71	1.0
Peanuts	68	0.5
Yogurt	68	-
Oatmeal	58	0.6
Wheat	54	0.4

Nutrition Strategy:  Consuming protein sources containing a BV of 70 or greater and a PCDAAS of 1.00, you will be providing your body the best proteins and amino acids.

So when trying to build muscle your best protein sources will be from animal sources!!