Author L. Rea on Protein Made Simple...

Protein Made Simple…Don’t Kill the Messenger!  (part 1 Publish in Planet Muscle Magazine Dec 2012)

So you just finished your all out performance or training session and slammed a 50g whey protein shake to take advantage of that all-important 90 minute anabolic window? Hmmm, well, studies now show that we only digest a small amount of most protein in liquid form. It takes 90 minutes for viscous liquids (e.g. a whey protein shake) to pass through the section of the gut that can actually absorb it. And the maximum rate that whey, and other proteins, can be absorbed is about 8-10 grams per hour (1,8,9,10). So you are only able to absorb about 8-10g of that 50g whey protein shake per hour. Since it passed through in 1.5 hours, and you absorb only 8-10g per hour your body only actually gets 12-15g average of that 50g of whey protein and 35-38g is now calories or toilet trash (1,2). Good investment, if you have a pay toilet. “If” your body was able to retain your entire 50g whey protein shake it would take about 5 hours to absorb. Kind of distracts from that so-called 90 minute anabolic window we were working in. The next point to consider is how much of that 12-15g of protein can probably be utilized for protein synthesis?

Before we continue, remember that all proteins are comprised of chains of amino acids that must be broken down into usable free and peptide form amino acids during digestion “before” the body can utilize any of the protein ingested for protein synthesis. So when discussing protein quality and needs, the end resulting amino acid ratio “post digestion” is what matters, not what whole protein you ingested. It’s the specific amino acids and their specific ratios that decide rate or percentage of utilization by the human body for protein synthesis…or conversion to glucose (gluconeogenesis) and/or fats and metabolic waste. There is no perfect 100% utilized protein found in nature, though nature can provide the materials to correct this, for up to a 99% AAU/NNU (Amino Acid Utilization/Net Nitrogen Utilization) utilized for protein synthesis.

First Attempts to Create an Advanced Human Protein

The idea of attempting to create protein powders with amino acid profiles that match human muscle amino acid profiles has become a popular method of marketing protein powders. One major flaw in this idea from inception is that the amino acid ratio profile found in human muscle itself is much different than total human physiological amino acid ratio needs for best physiological function. This also includes optimal health, and certainly for performance. It’s just dried food not human specific science. The EAA ratio will still be incorrect for optimal utilization for protein synthesis in humans.

Protein with Probiotics Added

This idea really has some good science behind it but it appears the science applied may have been to maximize or simply act as a sales tool. The first consideration one should have in regard to protein sources is not how much is absorbed, but rather how much is utilized specifically for protein synthesis. Probiotics can increase the bioavailability of nutrients. Probiotics are viable microorganisms that when ingested can exert biological effects and improve the absorption and utilization of the nutrients by the body. Obviously probiotics do increase the utilization of the protein source, but they do not create a total free or pep-tide amino acid source. So probiotics do increase the percentage of whole protein broken down to pep-tide and free form amino acids during digestion thus improve absorption and utilization. Good idea, but why add probiotics to increase bio-availability through increased amino acid content at a greater cost when a comparable free form amino acid formula would have the same benefits with less hassle, faster increased utilization for protein synthesis and lower cost? Additionally, the amino acid profile and ratios created due to probiotic inclusion are still not optimal for human protein synthesis utilization. Nonetheless, these products are a superior protein source compared to simple whey, casein soy or other dry whole food proteins. Unfortunately the EAA “ratio” will still be incorrect for “optimal” utilization for protein synthesis in humans.

There Are Only 8 Essential Amino Acids…

Realizing that the basis of human physiology for optimal systemic protein synthesis is centered around a fairly specific ratio of 8 EAAs and a couple of semi-essential amino acids is paramount to understanding protein intake needs. The correct human amino acid ratios take into account the correct necessary amounts of each individual EAA to be available for synthesis of the correct individual ratios, or individual amounts of  the other 14 semi- & non-essential muscle repair plus building…AND organ, enzyme, hormones and peptides production etc. all at the same time. Malnutrition, uremic toxicity, excess waste (toilet trash) and over-worked organs, such as the liver and kidneys, results when these needs are not met and the excess out of ratio amino acids must be utilized for glucose or fat production…or simply waste itself. Bottom line that and you get that there are only 8 Essential amino acids. The body can manufacture the rest of the 14 in the exact amounts it needs at the time. Sounds like a lot to take in but it is actually pretty simple once you have a few facts to wrap your head around.

The amino acids regarded as essential for humans are phenylalanine, valine, threonine, tryptophan, isoleucine, methionine, leucine and lysine. As sited prior, the adult human’s body can synthesize histidine but children cannot. And in some cases adults need to augment histidine and other semi-essential amino acid ingestion due to the scale below being an average rather than conditional profile for intake.

WHO (World Health Organization) recommended daily amounts and ratio currently in use for essential amino acids (EAAs) in adult humans, together with their standard one-letter abbreviations (7). Note the inclusion of the semi-essential amino acids Histidine, Cysteine and Tyrosine. (* Note: The WHO RDA is close to the actual ratio currently validated)

The Limiting Amino Acid Concept (Read this part twice)

The effective EAA content of any particular food is determined based on its lowest in proportion individual essential amino acid. In other words, the amino acid with relative proportion most bellow that in the ideal amino acid pattern profile, will reduce the use of all the others essential amino acids from that food protein by that ratio. An example would be Isoluecine.  This EAA has a minimum daily requirement of 20mg per kilo gram of body weight. If you only ingested 10mg per kilo gram of bodyweight daily, only half of the other EAAs ratios above could be utilized for protein synthesis. Nominal content of other essential amino acids exceeding the level determined by the lowest one, are effectively wasted thus become caloric or excreted waste. The amino acid that is lowest with respect to perfect EAA proportions is called the limiting amino acid, and the ratio of its relative proportion vs. relative proportion of that same EAA in the ideal (reference) protein is so called amino acid score (AAS). This does not solely apply to EAAs.  

At the level of the ribosome, the cells of eukaryotes require up to 22 different amino acids for protein synthesis. A shortfall of any one of these amino acids would thus be the limiting factor in protein synthesis. To further simplify the central most important fact regarding protein utilization for protein synthesis, consider this. If only 50% of any required EAA specific amino acid is present and the rest of the needed amino acids are all present at 100% requirement, then only 50% of the total protein/amino acid ratio will be utilized for protein synthesis by humans. However, eukaryotes can synthesize some of these amino acids from other substrates. Consequently, only a subset of the amino acids used in protein synthesis are “essential” amino acids (EAAs). Whether a particular amino acid is essential depends upon the species and the stage of development.

Cow’s milk and its whey or casein components where custom made with the right amino acid profile for cows thus humans can only utilize part of milk product protein for this reason.  A leading scientist named Rose showed that eight amino acids are essential for adult human beings, with histidine also being essential for infants (4). Longer term studies established histidine can also be essential for adult humans (3) though the human adult body can manufacture it from other EAAs.

The amino acids that are essential in the human diet were established in a series of experiments led by William Cumming Rose. The experiments involved elemental diets to healthy male graduate students. These diets consisted of cornstarch, sucrose, butterfat without protein, corn oil, inorganic salts, the known vitamins, a large brown "candy" made of liver extract flavored with peppermint oil (to supply any unknown vitamins), and mixtures of highly purified individual amino acids. The main outcome measure was nitrogen balance. Positive nitrogen balance means anabolism and negative nitrogen balance means catabolism. Rose noted that the symptoms of nervousness, exhaustion, and dizziness were encountered to a greater or lesser extent whenever human subjects were deprived of an essential amino acid (5).

In summery this simply means:

A)     That the human body needs EAAs in a specific ratio and amount daily that cannot be replaced with the other 13-14 amino acids that are non-essential, however the human body can use EAAs to synthesis all non-essential.

B)    Your body can only utilize 8-10 grams of protein per hour. Thus the most efficient approach to optimize protein synthesis would be to make the 8-10 grams ingested the correct human ratio of EAAs

C)    Most whole proteins such as eggs, milk, whey, beef, chicken, fish etc. are good for you but far from optimal for protein synthesis. But they sure do taste good!

D)    There will always be advancements in products and nutritional science just as there will always be personal preferences regardless of the facts science provides. Please don’t kill the messenger…

In Part 2 we will take a look at the paramount difference between:

1)     Protein Digestion

2)     Protein absorption

3)     Protein Utilization

Author L. Rea

References:

1)        Oben J, Kothari SC & Anderson; ML. An open label study to determine the effects of an oral proteolytic enzyme on whey protein concentrate metabolism in healthy males JISSN 2008 5(10).

2)        Helen Kollias, PhD

3)        J D Kopple and M E Swendseid (May 1975). "Evidence that histidine is an essential amino acid in normal and chronically uremic man.". J Clin Invest. 55 (5): 881–891

4)        Rose WC, Haines WJ, Warner DT, Johnson JE. The amino acid requirements of man. II. The role of threonine and histidine. J Biol Chem. 1951;188(1):49-58

5)        Rose WC, Haines WJ, Warner DT. The amino acid requirements of man. III. The role of isoleucine; additional evidence concerning histidine. J Biol Chem. 1951;193(2):605-612

6)        Young VR (1994). "Adult amino acid requirements: the case for a major revision in current recommendations". J. Nutr. 124 (8 Suppl)

7)        FAO/WHO/UNU (2007). "PROTEIN AND AMINO ACID REQUIREMENTS IN HUMAN NUTRITION". WHO Press., page 150

8)        Eur J Gastroenterol Hepatol. 1997 Jan;9(1):81-5. Absorption of hydrolysed bovine serum albumin from the human jejunum over a 6-hour period.

9)        J Clin Invest. 1973 Jul;52(7):1586-94. Protein digestion in human intestine as reflected in luminal, mucosal, and plasma amino acid concentrations after meals.

10)     http://www.muscle-insider.com/content/ca.....-g-protein  Dr. Scott Connelly (read the whole article)

11)     Joint WHO/FAO/UNU Expert Consultation on Protein and Amino Acid Requirements in Human Nutrition Geneva, 9–16 April 2002