Proteins in food

Yuck sis! Egg sandwich? What, you've never heard of proteins? I'm going to build up my muscles, so watch out! Whaaa?

Are muscles made of egg? Not quite, Michael. But muscles are mainly made of protein. And so is egg. So if you eat eggs, you'll get some of the building blocks that muscles are made of.

And proteins don't only build up muscle, but our organs and skin as well, and even hair and nails. But they don't go directly from food to the different body parts. First they must be split into smaller pieces, and then be reassembled again. All proteins are made of long strings of amino acids. All amino acids have the same backbone structure consisting of: Carbon, hydrogen, oxygen, and nitrogen.

So how do the various amino acids differ? That depends on what is attached to this carbon atom in the middle. It can have around 20 different side chains. Some side chains are small, some are large. Some contain oxygen, some nitrogen, and some sulphur.

Depending on how the amino acids are arranged - each protein can have very different properties. They can be hard - and form long fibres - like the keratin in your hair and in your nails. Or they can be water soluble and look more like balls - like the haemoglobin in blood. This is the substance that carries oxygen to all the cells in the body. There are small proteins that are only 50 amino acids in length. ...

and there are giant proteins with 30,000 amino acids. They are the largest molecules we know. Not all proteins are used as building materials in the body. Amylase for instance, helps the saliva in the mouth to break down food. Amylase is an example of what we call an enzyme.

Enzymes are a group of proteins that speed up chemical reactions in the body. We have about 75,000 different enzymes inside us. All have different functions. Enzymes need the right temperature and the right acidity to be able to perform well. If it gets too hot, they stop functioning.

That's one reason why it can be dangerous to get a high fever. Alright, alright, but we were talking about Jenny's yucky egg sandwich here. How can that turn into hair or muscles or those enzyme thingies? The proteins we eat are first broken down into amino acids. That decomposition starts in the stomach and continues in the small intestine.

These amino acids are transported by the blood to every single cell in the body, where they can be reassembled into new proteins. And it's the arrangement of the amino acids that determines the properties of each protein. Now, it doesn't make much a difference - for the building of muscle - if we eat just a little protein - or a large amount. How much you exercise, and in what way, is much more important. But we do need to get a certain amount of protein from food to survive.

But do I have to eat egg? I'm not fond of that. Don't worry, there's lots of protein in dairy products, fish, peanuts and bean sprouts. Bean sprouts, I like them. That's what I'm gonna put on my sandwich.

Yuck!