Nutrition Series: All you need to know about Proteins

People involved in health and fitness are familiar with nutrition and proteins and all that they do.

It would be hard to pick up, or read, anything related to fitness without seeing an article or advertisement about the benefits of consuming protein and making workout gains. Those that are new to the topic might have questions like:

1. What is Protein and why do we need it?
2. How does your body digest protein, what about excess?
3. How much protein does the average person need?
4. How does protein aid in muscle growth and recovery?

 

1. What is protein and why do we need it:

You might think of the obvious sources for protein like: animal proteins or perhaps dairy, but there are other protein sources that are not animal related like: legumes, nuts, seeds and soy products. Animal proteins are complete proteins in that they provide all the amino acids needed by the human body. Vegetable proteins are not complete, with proper planning you can create whole proteins by combining vegetable proteins.  The word protein comes from a Greek word meaning “of the first quality” due it the belief that it was essential to life.

Protein accounts for 15 to 20 percent of the human body and aren’t only found in muscle tissue.  Protein can also be found in hair, nails, eyes, tendons, ligaments, collagen, heart and GI tract. Proteins are also part of the metabolic, hormonal, immune and transport system, when combined, carry out important functions.

Which functions do protein offer? Forming red blood cells, forming hormones, helping to create enzymes which are helper substances to the metabolism, help to regulate fluid balance, regulates body fluid acidity, and helps to create antibodies.  Only 15 to 20 percent of muscle tissue is made up of protein, the rest of muscle tissue is water, stored carbohydrate and minerals.

Of course the most familiar role protein has is the ability to repair and rebuild muscle tissue.

Proteins, once digested, via the stomach, are broken down into 20 amino acids.  Eleven non-essential and nine essential (our body cannot produce essential amino acids, you must get them from your diet.) Once digested your body uses the separated amino acids in various ways within your body, amino acids are building blocks of hydrogen, oxygen, nitrogen and sometimes sulfur. At one end of the molecule is amene or nitrogen and the other end of the molecule is acid, hence the name.

• The essential amino acids are: Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Theronine, Tryptophan and Valine,
• The remaining 11 amino acids are nonessential because the human body can create them within the body. Alanine, Cysteine, Cystine, Glutamine, Glutathione, Glycine, Serine, Taurine, Threonine, Asparagine and Apartic Acid.

Amino acids are part of a complex system that helps regulate various aspects of your metabolism. Amino acids do not work alone, this task requires a group effort between the amino acids, minerals, carbohydrates and fatty acids.

Out of the 20 amino acids three of them have branches or chains, called branch chain amino acids (BCAA) the BCAA’s are leucine, isoleucine and valine.  While the other amino acids are metabolized in the liver, the three branched chain amino acids go past the liver and head directly to the periphery, or the muscles away from the core.  It is reported that BCAA’s can be used by the body for an energy source, repair, maintenance or muscle tissue rebuilding.

2. How does the body digest protein, what about excess?

Our bodies don’t store proteins long-term like we do carbohydrates and fats, instead our body uses proteins as they are digested.  Once broken down the amino acids circulate looking for work in their field for a set period of time. If there are more amino acids than needed the body converts any unused portions into glucose for immediate energy or stored fat.

To transform amino acids the liver strips the nitrogen off the amino acid molecule then it sends the remains off to be burned as glucose energy (unused glucose energy is stored as fat).  The stripped off nitrogen can then be used for DNA, RNA, a non-essential amino acid or it might also be converted into ammonia or urea, which then is sent away as urine. When consuming large volumes of protein your body will need an increase of fluids to help with the extra process of breakdown and conversion. For an athlete, staying hydrated can be a challenge, this challenge increases with the additional protein ingestion.

The human body has mechanisms to protect itself from having too much protein. One of the first forms of protection is to slow down digestion in the stomach, too much protein can make you feel fuller longer, or, if it remains in your stomach too long, can cause nausea.

3. How much Protein does the Body Need?

There is a heated debate between the “How much Protein is too much” camps.  A look at any book store shelf shows a wide range of “diet plans” running from high protein, high fat or high carbohydrate; it’s no wonder we are all so confused and struggling for answers.

I am reading in “Nutrient Timing for Peak Performance, ” they state that our bodies can not use more than 2 or 2.5 grams per kilogram of protein daily, or even less.  in that same book they mention that according to Robert Wolfe PhD, the maximal effective amount of protein is 20-35 grams at any one time.   Dr Wolfe states that when the body consumes any amount of protein over and above what it needs urine outputs increases. Indicating that the excess protein is passing through your liver, some of which used as energy or stored as future energy in the form of body fat.

The much debated question of how much protein is one that has been in the headlines for the last few decades. Consumption of animal products has more than doubled in the last decade and perhaps this debate could be one reason for that sharp consumption increase.

Nutrient Timing for Peak Performance has the recommended dietary amount or RDA for adults over 18 is .8 grams per kilogram or per .36 grams per pound of body weight. Younger children need more protein during their growth period (ages 4 – 13)  .95 grams per kilogram or .43 grams per pound of body weight. Children between 14 and 18 require .85 grams or .39 grams per pound of body weight.

These amounts are the required amount, however they state that athletes require a higher amount of protein.

Another consideration, if you are getting the majority of your nutritional calories from protein sources you might not ingest enough carbohydrates for fuel.  While your body can convert proteins into energy it takes longer and requires more fluid intake and is taxing for the liver.   Also, consuming a high protein meal right before exercise can make your activity seem harder to perform due the body having to digest and process the protein, this is especially true for endurance athletes.

4. How does protein aid in muscle growth and recovery?

Athletes need more protein due to the muscle repair and rebuilding that training creates within tissue. Athletes consume additional amounts of protein to maintain health, support muscle growth, preserve bone integrity and help to keep their overall body weight.  Your level of training and also level of athletic fitness will determine your additional protein needs.

Muscle breakdown and repair can take 24 to 48 hours to fully restore post exercise. However in the first hour after training your body is replenishing at a much higher ratio. At this time a quick digesting protein, like a whey protein isolate, in addition to carbohydrates, would be your best option.  While a quick digesting and absorbing protein is good in the first few hours post workout, a slower to digest protein can help fuel the repair over time.  The reason for this is due to our inability to store protein, if muscle repair takes time you then want a slow to digest protein to fuel the muscle repair to its fullest potential. You wouldn’t want to train hard then leave the tank empty,  giving your body no resources to rebuild its tissue, this would cause a negative build situation.

Proteins also absorb at different ratios as our digestive tract only processes, and allows, so much into our bloodstream at a time.  Different sources process at different ratios, for example, our bodies only absorb 2.8 grams of cooked egg protein per hour.  With one egg having 6 grams of protein it stands to reason then that two eggs or 12 grams of protein would take 4 hours to digest and absorb. These slow to digest proteins are good to eat around training to further fuel the long road to rebuilding.  While fast absorbing proteins might be seen as beneficial immediately after training the slow digesting protein also have a role in rebuilding muscle.

Interesting continued reading:

According to this Wikipedia breakdown: The Food and Agriculture Organization has created a rating system for proteins called the PDCAAS or Protein Digestibility Corrected Amino Acid Score. This takes digestibility and how well-rounded the food supply is with regard to how well we can digest it.

I have discussed the basics of proteins in this post, my next post on proteins will focus on the different types of proteins and how they impact us during training, including the timing aspect.