Tag Archives: amino acids

A New Source of Protein for the Athletic and the Sedentary?

A New Source of Protein?

This is an odd and interesting bit of research.  It relates to reaborption of nitrogen . . . and presents the possibility that more protein is conserved than previously thought.  First dietary nitrogen 101: Nitrogen is a major component of amino acids.  Amino acids are needed to form proteins.  We can synthesize some amino acids ourselves, but others need to be obtained through diet.  Dietary protein provides nitrogen and amino acids from plant or animal sources which are resynthesized into human proteins.  Unused nitrogen is converted into Ammonia and Urea and excreted.

Can nitrogen be reabsorbed from the intestines?

WODMasters Eye Pood Kettle Bell
Even if you don’t have the right microbial stuff, you can still look awesome and powerful with the right shirt

The answer is a shocking “maybe.”  A new nutritional study (published ahead of print in the Journal of Nutrition) has found that nitrogen appears to be reabsorbed.  This makes little sense at first glance.  Until we consider the vast populations of microorganisms that reside in the gut.  Until recently, they were all thought of as “germs” that needed to be quashed.   That has changed.  We are learning more and more about how important they are for our health and even our survival.

The study is titled:

Nonprotein Nitrogen Is Absorbed from the Large Intestine and Increases Nitrogen Balance in Growing Pigs Fed a Valine-Limiting Diet.

Valine is an essential Amino Acid, so these animals were fed a protein-deficient diet.   Then researchers administered urea or casein into the cecum of pigs.  Let’s consider this research a step toward greater understanding of how nitrogen may be recycled in living animals.  Not a new way to increase protein for strength.  (Although who knows.  It might work.) The urea was synthesized using Nitrogen-15.  Dietary nitrogen is Nitrogen 14.  Using nitrogen-15 lets the team know where the cecum-delivered nitrogen ended up.

Findings:

Researchers found that more than 80% of the cecum delivered nitrogen was absorbed.  Some of it was excreted in urine, but some was retained. This is a shocker.  I know.   Humans cannot synthesize protein using nitrogen.  So WTF?  The researchers propose that urea traveled through the bloodstream and into to the small intestine.   Bacteria (some of which can make amino acids using urea or plain nitrogen) in the small intestine then used the extra urea to make amino acids.  Amino acids produced by bacteria could then be absorbed the host (animals).

Takeaway:

More research would need to be done to confirm that this happens.  But it is very interesting.  Humans vary in the types of bacteria they host.  Bacterial populations vary according to diet, environment, chance (?) and who knows what else.  Do people get extra protein from bacteria?  Does this happen under normal circumstances (i.e. not piped in through the back end.)?  One thing is sure: there is a lot to learn. ResearchBlogging.org

Columbus DA, Lapierre H, Htoo JK, & de Lange CF (2014). Nonprotein Nitrogen Is Absorbed from the Large Intestine and Increases Nitrogen Balance in Growing Pigs Fed a Valine-Limiting Diet. The Journal of nutrition PMID: 24647394

What causes fatigue? Why is it different in CrossFit?

What causes fatigue? And why is it sometimes so hard to push through it?

Few people enjoy the sensations of fatigue and pain that accompany intense exercise.  While endurance athletes may get a “runners’ high” that feeling of elation is not common during a CrossFit WOD or in other forms of intense physical output.  The runners high is thought to be caused by feel-good chemicals produced by the brain that blunt pain and allow people (and animals) to run for long distances.  You can read up on these chemicals (endocannabinoids) here.  Without them you will feel very differently.  There are several thoughts on what causes fatigue.  Possibilities are:

Kelly and Squared
CrossFit WOD Open Competition Athlete and Judge

 

  • Build-up of metabolic by-products
  • Signals produced by the brain that try to tell you “that’s enough”
  • Production of inflammatory cytokines
  • Signals from the body that enter the brain to tell it “stop.”

Is buildup of Ammonia a factor in Fatigue?

It may be.  Ammonia builds up in blood just a little during moderate intensity exercise.  But it increases rapidly when levels of effort are heavily ramped up.  And it increases during prolonged (over an hour) sub-maximal efforts.  The buildup of ammonia may be caused by the breakdown of Branched Chain Amino Acids (BCAA’s).  When ammonia builds up in the blood it can enter the brain and cause problems.  Including stupor.  Maybe this is part of what happens to marathon runners.

Caffeine, Amino Acids and Escaping Fatigue

Caffeine has been shown to reduce fatigue and improve athletic performance.  Caffeine also changes the manner in which amino acids (and BCAA’s) are metabolized during exercise.  Perhaps one of the ways caffeine helps workouts is by reducing the amount of ammonia build up.   Meanwhile, it seems that supplementation with glutamine suppresses fatigue and ammonia build-up.  Glutamin is considered a non-essential amino acid, but there is growing evidence that it might be particularly important under intense exercise.  Good sources of glutamine include beef, chicken etc. as well as wheat.  This is not the same thing as MSG (mono-sodium glutamate) which can trigger nasty headaches in many people.  Supplementation with branched-chain amino acids may also suppress build-up of ammonia as well.  We’ll see what comes up in the next few years.

 

Bassini A, Magalhães-Neto AM, Sweet E, Bottino A, Veiga C, Tozzi MB, Pickard MB, & Cameron LC (2013). Caffeine Decreases Systemic Urea in Elite Soccer Players during Intermittent Exercise. Medicine and science in sports and exercise, 45 (4), 683-690 PMID: 23135367
Wilkinson DJ, Smeeton NJ, & Watt PW (2010). Ammonia metabolism, the brain and fatigue; revisiting the link. Progress in neurobiology, 91 (3), 200-19 PMID: 20138956

Bassini-Cameron, A., Monteiro, A., Gomes, A., Werneck-de-Castro, J., & Cameron, L. (2008). Glutamine protects against increases in blood ammonia in football players in an exercise intensity-dependent way British Journal of Sports Medicine, 42 (4), 260-266 DOI: 10.1136/bjsm.2007.040378