What is Protein and Why is it Important?

What is Protein? Protein is You!

So, what is protein, you ask? Well, before I can answer this question, let’s first consider what amino acids are. In short, amino acids are small, nitrogen-containing molecules that link together to form peptide bonds, you know, like links of Italian sausages. Lots of these links (a.k.a. peptide bonds) result in a polypeptide chain and long polypeptide chains can be classified as proteins!

Basically, there are 20 different amino acids that link together in a certain sequence (and chain length) that results in a certain function. For example, serum album is a protein that acts as a transport system for many types of molecules. Its amino acid sequence allows it to pick up certain particles and drop them off when they get to the target tissue.

What is Protein?: Life!

There are huge numbers of combinations of amino acids – this is why we can have so many different kinds of proteins! All those digestive enzymes, kinases, synthases, proteases – the list is endless! As a matter of fact, we still don’t know about all the proteins in our body. There’re more than 50,000 of them!

But where do these amino acids come from?

Your diet! There are both essential and non-essential amino acids. If you’re not getting enough protein in your diet, you’re body will struggle to rebuild muscle and synthesize essential proteins that are required for overall bodily function. But, if you’re getting a balance diet with enough protein, you shouldn’t have any problem in that area.

What is Protein? Your structure!

The answer is DNA (Deoxyribonucleic Acid). This is the genetic material that makes you what you are! In a nutshell, strands of DNA are transcribed into messenger RNA (Ribonucleic Acid) which then leaves the cell nucleus and heads towards the ribosomes. Ribosomes then decodes the mRNA into a specific sequence of amino acids that are created in a growing chain. Long story short – DNA makes mRNA, mRNA encodes an amino acid sequence, the specific amino acid sequence makes a protein!

Easy, right? It’s just that simple

Pop Quiz!

Q: What is protein?A: Proteins are large molecules composed of nitrogen-containing amino acids.

This is important – you’ll come across references to keeping a “positive nitrogen balance” in your diet in order to build muscle. This simply means taking in more protein than you excrete. So now that you understand what proteins are and how they’re made, let's dive into how your body uses the protein you take in.

What is protein? Your proteins!

Basically, your body uses proteins to maintain structural tissues such as bones, muscles, hair, teeth, elastic fibers and the cell membranes of all the cells in your body. A large majority of the protein you take in on a daily basis goes into the creation of enzymes.

These are like little "test tubes" in which essential reactions can occur more easily than if the enzyme weren't present. In other words, an enzyme creates a specialized environment for the reaction of two specific molecules. They're required for every single bodily process that your body undergoes from nerve impulses, digestion of foods, formation of energy and many other basic physiological functions.

What is Protein? Your function!

Upon ingesting a nice steak, your stomach and secretes acid (hydrochloric acid) and digestive enzymes (trypsin and chymotrypsin among others) which break down proteins into short peptides and single amino acids. It's like breaking the links between the sausages so you can eat them individually!

Symport pumping systems located in your small intestine take up these amino acids and small peptides. These peptides can be used to create other body proteins (nucleoproteins, glycoproteins, neurotransmitters, and many many others), they can be metabolized for energy, stored as fat or used to repair and rebuild muscle fibers.

After the synthesis of proteins, unused structures are shuttled to the liver where they're metabolized for energy or excreted in the urine.

With that in mind, every single day you're excreting used, old and overused proteins in waste products (including your hair and nails). In fact, you end up reusing more proteins every day than you take in with the diet. It's important to make sure you're getting enough protein in your diet to account for the turnover! If not, your body will end up digesting it's own protein storages (a.k.a. your muscle fibers - remember that your heart is a muscle!) to create the enzymes and proteins your body needs to survive. Having lots of muscle is secondary to survival.

What is Protein? Essential!

There're 20 basic and common amino acids your body uses to create all the proteins in your body. Good news is, you don't have to get all of them from your diet! In fact, your body can readily synthesize 10 of these amino acids from fats, carbs and other proteins or peptides.

With the same token, your body cannot make the other 10 amino acids. These are known as the "essential amino acids" since you must get them from the food you eat.

You'll notice the asterisk (*) I placed near Tyrosine. This amino acid is actually pseudo-essential since it's made from Phenylalanine. So, if you're not getting much phenylalanine, as in those individuals with phenylketonuria (a disease in which phenylalanine byproducts accumulate and become toxic), then Tyrosine becomes an essential amino acid.

For the sake of completeness, Histidine and Arginine are only essential in young children while nonessential in adults! As you see, the body is very complex...

What is protein? Quality!

Nutritionists often speak of the quality of proteins - but what does this really mean? Simply speaking, we're all animals. In fact, humans share many proteins with the animals we consume. So, when we eat animal products, we obtain similar combinations of amino acids, peptides and proteins that we have in our own bodies. This is what makes a protein high quality.

These sources of protein (dairy, meat, fish, poultry, eggs) are more quickly and efficiently absorbed by the body without much in the way of byproducts. Why waste anything?

When a source of protein contains all the essential amino acids, it's known as a complete protein (and high quality!). And yep, you guessed it, incomplete proteins do not contain all the essential amino acids (low quality). These proteins come from fruits, vegetables, whole grains, beans (except soybeans!), and nuts.

This is usually measured with reference to the egg, which is taken to be the best source of complete proteins. It's not just the amount, but the quality of protein that counts.

In other words, just because a nut may have more protein than a small piece of hard-boiled egg yolk doesn't mean the nut is better for you. The egg has all the essential amino acids and is therefore labeled as more nutritious and complete. This is sometimes measured using a so-called amino acid score which simply indicates the quality of the protein product in question.

Should you stay away from low quality proteins?

No! In fact, it's quite easy to mix and match to make sure you're getting all the essential amino acids. For example, if one item you eat doesn't have a few of the amino acids, then you can make up for it with the next meal or other items on your plate. This matching of foods creates the full complement of amino acids, so there's no need to only eat proteins that are coined "complete." It's actually a natural occurrence that we mix and match sources of amino acids - we don't necessarily need all of them at every sitting.

What is protein? Your diet!

The recommended daily allowance indicates that men should get about 52 grams of protein per day while women should eat about 45 grams. But remember, this really depends on your activity. For example, if you're weight training, you're going to need more protein. This happens naturally, though!

When you start strength training, you simply need to ingest more calories. This alone means you'll be getting more protein which is probably enough to support muscle growth (most Americans eat too much protein as it is!). I wrote a page on proteins and building muscle along with a daily diet plan to help plan your eating.

What is Protein? A new you!

Anyone who's creating new tissue needs more protein. A good example here is a pregnant or lactating woman for obvious reasons. Other examples include those who have had injuries (this is mainly to prevent the destruction of already-existing tissues), have been through surgery and those who have healing wounds. Again, any situation in which new tissue must be made is a place where extra protein might be in order.

What about athletes? This isn't a good example. Why? Because athletes eat more food to begin with to support their training programs. This alone means they'll be taking in more protein in their regular diet without even thinking about it.

Can you eat too much protein?

Yes! An individual taking huge amounts of protein over long periods can result in kidney stones and/or kidney failure later in life. What happens is that uric acid crystals build up in the kidney tubules because charged proteins block the passage of uric acid into the urine. So they simply build up until kidney stones form. Uric acid can also build up in the blood, causing a debilitating, painful condition known as gout. This are situations in which a low-protein diet may be in order.

With respect to your strength training program, taking too much protein can also be detrimental. Check out the page on protein to build muscle and high protein diets for more information.

What is Protein? Required.

If you don't get enough protein, the first thing to go awry will be your muscles. They're the most dependent on your protein intake, so this is easy to imagine. Blood proteins will be low, fatigue will result, hair loss may occur and muscles will noticeably shrink. You may also have a fluid imbalance since blood protein concentration (namely albumin) determines how much fluid moves in and out of arteries and veins.

Bottom line? Protein is essential for all of life's processes. Getting too much or too little can have it's problems, so make sure you're eating a balanced diet of good, quality proteins to make sure you're getting everything you need.