Protein Science: Learn How To Decode The Ingredients on a Tub of Protein

[MattShwed]

Proteins? Aminos? What?

If you’ve been around the weightlifting/bodybuilding scene for any amount of time you’ve probably seen how much everyone talks about protein. Whey protein, casein, plant protein, protein shakes, protein foods... the list goes on and on. But have you ever wondered what the body is actually doing with those proteins? What those proteins actually are? and how they are used in the body?

It's my goal to provide clear facts on proteins and how the body uses them.
In this article you'll learn:

1. Learn what proteins are made of
2. Learn how to decode the list of ingredients on a tub of protein
3. Make your friends think you majored in biochemistry

To sum it up, proteins are essentially big huge organic molecules. Organic in this sense doesn’t mean they were created using good farming practices. Rather, organic compounds in this context refer to compounds made of elements located in certain areas on the periodic table. (That big chart you probably saw in your science classroom) Our entire bodies are made of organic elements!

Okay, so if proteins are big huge organic molecules, what do these structures look like? Well, proteins are made of long chains of smaller organic molecules. But this leads to another question... if a big protein
is made up of a bunch of little molecules all strung together, what do these smaller molecules look like?

This is a great question. The essential building blocks of protein are a type of molecule known as an amino acid. Ah now this may sound familiar! You might have heard about BCAAs as a supplement. BCAAs stand for (Branched Chain Amino Acids). They are the building blocks of protein! Amino acids play a vital role in human metabolism and the biochemistry of life.

Breaking It All Down

To understand how this all works lets examine one of the most important proteins in our bodies: hemoglobin. By gaining an understanding of how this protein works we can understand how proteins work in general.

When you are working hard at the gym and breathing deeply, hemoglobin is the protein responsible for making sure your body is getting the oxygen to your cells! Without it, you’d be dead!

We can undestand this by imagining hemoglobin as working like a car and oxygen like the passenger. Hemoglobin delivers the
oxygen to tissues in your body (like your muscles). The cells will then use this oxygen to generate ATP (Adensine Triphosphate). This is the energy source powering ALL THE ESSENTIAL BIOCHEMICAL PROCCESSES IN YOUR BODY keeping you alive!

So where do amino acids fit in?

Proteins like hemoglobin are made of these amino acids. Just like different cars are made of different components so too are proteins! The engine and most of the components in a Ferrari work quite differently than a Toyota Prius. Just as cars come in many shapes and sizes all with different purposes, so too do proteins.

The 21 amino acids in the body come together to form many many different types of proteins (or cars). Our body uses 21 different types of amino acids to generate the wide range of proteins found in our bodies. The 21st amino acid “selenocysteine” was discovered relatively recently.

The Building Blocks of Aminos (some biochemistry incoming!)

Aminos are made of two primary chemical structures.

1. An Amino Group (NH2) (This just means 1 Nitrogen, and 2 Hydrogens)
2. An Acid Group which in the aminos case is a Carboxylic acid

A carbon atom is what links the amino and the carboxylic acid group. Amino acids also have what is called an R group attached to them. This is typically any side structure attached to the amino.

Each of the aminos all share this same typical structure, but what makes each amino unique is the variations in the R GROUP side chain. Each of the 21 amino side chains looks different.

Going Deep on Biochemistry

For those who want to go deeper, that carbon linking the amino group and the carboxyllic acid group is typically called an alpha carbon and is also a chiral carbon.

Chiral carbons are just carbons with four other groups attatched to it. In the case of an amino we have:

1. The R Group
2. The Amino Group
3. The Carboxylic Acid Group
4. A lonely hydrogen atom

Chirality is a fascinating chemical concept having to do with the optical activity of a molecule. When polarized light is shone at an amino acid, it will rotate towards that light. Simple as that.

What This Means to Bodybuilders?

If you’ve ever looked on the ingredients in your proteins or BCAAs you may have noticed some of the amino acids are prepended with a L or D like L-Leucine or L-Valine or L-Isoleucine. What is this all about?

The difference between the L and the D has to do with something called chirality and Fischer projections.

Without diving too deep on this essentially L and D aminos are like your left and right hands. Mirror images of each other.

Fun fact: D refers to dextro which comes from the latin word dexter (meaning right)

HOWEVER In the human body you are only going to find L amino acids, which is what you’ll typically see in a BCAA bottle

Now whenever your friends ask about aminos, you’ll sound like a biochemist!

How Proteins are Absorbed in the Body (an introductory guide)

Now that we understand what proteins are, let’s understand what happens when you ingest a large quantity like you might in a protein shake. Understanding how proteins are absorbed will help illustrate their purpose.

Stage 1) The Mouth

Digestion starts immediately, as soon as you put food in your mouth. For example that delicious high protein chicken breast you just cooked up. After cutting off a portion and putting it in your mouth, the enzymes in your saliva immediately begin to try breaking it down. If there are any carbs you are eating with the chicken, such as brown rice, salvitory amalyse (the digestive enzyme in your saliva) begins breaking down the carbs. As we chew and digest our digestive systems will continue to break down food until it’s small enough that it can be absorbed.

Food sources or our macronutrients come in 4 different flavors.

1. Proteins -> which get broken down to Amino Acids
2. Carbs -> which get broken down to Glucose
3. Fats -> which get broken down to fatty acids
4. Nucleic Acids -> Nucleotides

Stage 2) The Stomach

After that protein packed chicken breast makes it way down your epiglottis, it reaches your stomach. The stomach really takes a scorched earth approach to digestion. It churns and contracts and expands mixing up the food with the stomach acids or gastric juices. This gastric juice is made up of a bunch of stuff, primarily:

1. Hydrochloric Acid
2. Pepsin
3. Mucus and Water

FUN FACT: This hydrochloric acid has a ph of about 1.0. strong enough to give you a chemical burn if you got it on your hand. This acid hopefully kills most of the bacteria on the food. You may be wondering how we don’t end up digesting our stomach! The mucus is extremely important as it lines the stomach to prevent the acid from giving you ulcers!

So How Does This Protein Get Broken Down?

This is where PEPSIN comes into play. Pepsin begins breaking down the proteins in that chicken into amino acids which we learned about earlier. Pepsin breaks down the peptide bond holding all the amino acids together in the protein! Kind of like breaking apart a lego house into individual bricks!
After this mixture has been churning, you are left with a digestive soup... called chyme. Now your stomach has a sphincter which regulates how much of this chyme is able to get into your small intestines.

Step 3) The Duodenum

This is where the real action begins. Here, bicarbonate is secreted to neutralize the hydrochloric acid so it doesn’t damage your small intestine! Further lots of absorption takes place here!
The pancreas plays an extremely important role in secreting the most important digestive enzymes like pancreatic trypsin and chymotrypsin which are used for digesting proteins further!

After food passes through the duodenum, the digested food passes to the small intestines.

The small intestines are extremely long and have a huge surface area for absorption. It is here that proteins can be shuttled around the body and to your liver to be stored!

Using something called primary active transport the small intestines are able to absorb these molecules and get them to start building muscle!

To make this more clear. On a single (enterisite) intestinal cell we have a protein on the cell membrane which cleaves off one of the phosphate groups on ATP (The energy of life) allowing the amino acid to enter the intestinal cell! Eventually it will make its way to a blood capillary to be shuttled to where it needs to go in the body.

And that is how digestion of proteins occurs!

And That's That!

In this article we examined proteins from the ground up. You now not only understand proteins from a biochemical perspective but now understand how they are processed and used within the body. Proteins are extremely complicated and although we’ve only scratched the surface you’ll be able to use this knowledge to recognize and explain some of the foods you’ve been consuming!

Hope you've enjoyed

[richardmf]

excellent article and thoroughly well written!!

[MelanieBallan]

Thanks for all the great information. Very concise but thorough article!