Do you know about Biological Value??

The Biological Value

Biological Value (BV) is a method of measuring the amount of “Protein” utilized in the body. It can be defined as “The nutritional effectiveness of the protein in a food” too. 

The main Nitrogen source of the human body is Protein. So the amount of Nitrogen is used to measure the Biological Value. It can be measured by calculating the percentage of Nitrogen incorporated into the body from the amount of Nitrogen absorbed by the diet. This gives the idea of the efficiency of the food. 

BV is a good measurement of protein quality too. Proteins with high Biological Value enhance better Nitrogen utilization in the body and reduce the wastage as urea through urine. It reduces the protein requirement of the body by utilizing already absorbed protein as much as possible. When the BV of a protein decreases, the amount of protein to get the maximum effect increases.  

How to calculate.?

BV is calculated as a percentage. The simple formula is given as follows,

BV = (Nr/Na)*100

Where Nr is the Nitrogen incorporate into the body via the test diet and Na is the Nitrogen absorbed into the body via the test diet. Nr is measured by the amount of Nitrogen secreted through fecal matter and urine. 

But for more accuracy, this equation is derived as follows,

BV = [ ( Ni - Ne(f) - Ne(u))/ (Ni - Ne(f)) ]*100

Where the Ni means the Nitrogen intake of proteins from the diet, Ne(f) means the difference between the Nitrogen excrete in feces whilst the test diet and Nitrogen excrete in feces, not from the diet.  And the Ne(u) means the difference between the Nitrogen excrete in urine whilst the test diet and Nitrogen excrete in the urine, not from the diet. 

BV can be any value between 0 to 100

What is the best protein source?

Egg proteins are the best proteins that can be utilized most efficiently. It has approximately 94% of BV. Eggs have all the essential amino acids in their proteins. There are 40 different kinds of proteins where the Ovalbumin is the major protein. BV of milk is 85% and they are the second-best protein source. Milk contains two major protein groups called casein and whey. Whey proteins are absorbed into the body much faster than casein. 

BVs of some food are as follows, 

Beef - 80%

Chicken - 79%

Soybean - 64%

Corn - 60%

Peas - 55%

Human breast milk - 95%

What are the factors that affect BV?

The main factor is the composition of protein. There are essential amino acids that need to be taken through the diet. For humans, there are 9 essential amino acids that cannot be synthesized in their bodies. If a protein does not contain any amino acid out of them, the BV can be decreased. 

Some Vitamins and minerals are essential for the proper functioning of cells. Therefore it affects protein utilization too. So the vitamin and mineral composition also critically affects the BV. 

When processing food, some proteins can be destroyed (sterilization, pasteurization, frying) because of high temperatures. Need minimal processing technics to retain nutrients in the food. 

What is the importance of choosing food items with high BV? 

When consuming proteins that have high BV, you can obtain better nutrition from a lower amount of food. This can be used in diagnosing diseases too. 

article by: Sajith Pushpakumara