Q & A Thursday: do you need to worry about the biological value of protein?

Posted by kathryn in Protein and Q & A Thursday

Next on Q & A Thursday Chloe wants to know about the biological value of protein – what it is and how to use this information.

This is a tricky concepts. It’s hard to explain and an important nutritional principle. But (thankfully) it can also be translated into simple dietary guidelines. Stuff you can follow, without tracking numbers and doing complex calculations.

I’m mostly going to answer this question by linking back to a previous post. In a previous Q & A Thursday I wrote about how vegetarians can get enough protein. This post contains an explanation of biological value and how it relates to different foods. Read this post before continuing, otherwise the rest won’t make sense!

High or low biological value – which is better

Unlike the GI or cholesterol levels, when it comes to biological value the higher the better.

While protein is found in a huge range of foods it’s animal foods which have the highest biological value. They most closely match our amino acid requirements.

In contrast plant-based foods have a low biological value. They contain low quantities of one or more of the essential amino acids. They are the furthest match from our amino acid requirements.

Do you need to worry about biological value?

In theory the low biological value of plant proteins seems to indicate vegetarians are protein deficient. And that animal based foods are the only ones to eat – their higher biological value makes them better?

However, in practice this is not actually the case. By varying the plant proteins you eat, you can counter-act the amino acid deficiencies. One plant group can make up for the inadequacies of another, effectively balancing out the amino acid profile and making it a closer match to your requirements.

By consuming grains, legumes, nuts, soy foods you are effectively raising the biological value of what you’re eating.

You don’t have to eat all of these in one meal, or even in one day. But over the course of a week vary your protein sources and you don’t have to worry about biological value.

Yet again, it’s through eating a variety of foods that you gain the best nutrition.

What is Q & A Thursday?

This post is part of Q & A Thursday – a monthly burst of blogging, where you get to dictate the subject matter. Q & A Thursday is all about simple, practical answers to food and diet dilemmas sent in by readers.

For more information you can take a look at the Q & A Thursday archives.

03 July, 2008