Protein is one of the most important building blocks in our bodies ...
Protein is second most abundant substance in our body; it is second only to
water. Protein makes up much of the structure of our body, including: our
muscles, ligaments, tendons, bones, organs, glands, nails, and hair. It also
makes up the vast majority of the molecules that allow our bodies to
function and regulate itself; protein is required for: cell signaling
molecules, hormones, transport molecules and most enzymes in our bodies,
including our digestive enzymes. For more information on enzymes, please
click here. Without sufficient protein, our bodies cannot function properly.
DNA – The Code for Proteins
Our genetic material (DNA) is the blueprint that shows each cell how to
produce the proteins that make life possible. It is differences in this
coding that makes the variations of our proteins that make each of us
unique. For example, it is protein in the iris of our eyes that gives us our
distinctive eye colours.
What is protein?
Proteins are composed of building blocks called amino acids. These subunits
are linked together by peptide bonds to form chains that can be straight
lines, or branched like the sub-branches on a tree. When we eat protein the
body must break these peptide bonds in the digestive tract using proteases
(for more information on proteases, please click here). Then single amino
acids, or amino acids in short chains (called peptides), are absorbed
through the gut, into the body, where they are used as building blocks to
create whatever protein the body needs.
Essential Amino Acids
Some amino acids are considered "non-essential". This means that we do not
need to ingest these amino acids, because our bodies can biosynthesize them
using the skeleton of other amino acids. So long as the body gets sufficient
protein, these amino acids are not required. The amino acids that the body
cannot produce itself need to be taken in through the diet, and are called
"essential" amino acids. There are 9 essential amino acids: isoleucine,
leucine, lysine, methionine, phenylalanine, threonine, tryptophan,
histidine, and valine. Some amino acids are "conditionally essential",
meaning that certain populations who naturally don't make enough, or all
humans under certain conditions, may require certain dietary intake to meet
their needs. Some examples of conditionally essential amino acids are:
arginine, glutamine, cysteine, and glycine.
Protein is an easily available energy source for the body. When insufficient
protein is ingested in the diet, or insufficient calories are taken in, the
body will catabolize protein from muscle mass and then eventually from the
organs to cover the deficit. This breakdown of body tissue can even happen
before exhausting fat reserves. As protein levels drop, the body will
prioritize protein usage to enzymes and signaling molecules to continue
proper bodily function, and will catabolize other tissues to do so. As such,
insufficient protein or calorie intake results in protein malnutrition,
which causes muscle wasting, and eventually can lead to the breakdown of
organs, and tissues. Eventually this causes a condition known as
Kwashiorkor, which causes diarrhea, edema (swelling) and a large protruding
Protein and Weight Loss
It is important to note the connection between low calorie diets and loss of
muscle mass. Those individuals seeking to lose weight who overly restrict
their dietary intake will ultimately lower their muscle mass. This is
counterproductive, as our muscles are the body tissue that burns the most
calories by weight. From a biological perspective, the body's response makes
sense; when food is scarce, reducing the amount of calorie burning tissue
you have, allows you to live with lesser requirements until food can be
found again. In modern society, this leads to the inability to lose weight
despite a calorie-restricted diet. Recently, the popularity of high protein
diets has made supplementation of protein popular for weight loss. When
protein is ingested with carbohydrate, it slows the rate at which sugar
enters the body. By avoiding spikes in blood sugar, protein minimizes the
storage of sugar as fat. Individuals with blood sugar imbalances, like
diabetes and hypoglycemia, will benefit from protein's regulation of blood
sugar. Because protein also builds muscle tissue, which burns more energy
than other body tissue, it can also help weight loss.
According to the Canadian Dietary Reference Intake guidelines: sedentary
adult women require 46 grams of protein per day, while sedentary adult males
require 56 grams to avoid deficiency. This is just the amount to prevent
protein malnutrition. Athletes and individuals who are physically active at
work or play will all require additional protein to repair their tissue and
build more lean muscle. People who are recovering from illness or long
periods of inactivity require additional protein to rebuild their lost
muscle mass as well. The immune system is dependent on protein to make the
cells and antibodies that protect our body. Frequent colds and flus and
chronic infections are signs that the body may need more protein. In
general, the recommendation is between 1.5 and 2 grams of protein per
kilogram body weight daily intake for fairly active people. This is around
125g of protein per day for a 70kg (155lb) person.
The body is incapable of storing protein, so when we ingest it in much
larger amounts than the body needs, excess protein has to be broken down.
The extra amino acids are transported to the liver where they are broken
down to create energy. Although an easy energy source, protein does not
"burn clean", and breaking it down creates a waste product called urea.
Normally this is easily excreted through the kidneys in our urine. This
excretion requires calcium, so high protein diets should be combined with a
calcium supplement to protect against reduced calcium stores.
Protein powders can be used for many different health and performance
enhancing purposes. There are a large variety of readily available protein
supplements and protein processing techniques. The six main supplemental
sources are: whey, egg, hemp, soy, rice and pea, although other sources are
occasionally used in some supplements. Higher quality formulas use superior
processing techniques, and avoid binders, fillers, artificial flavorings and
sweeteners. Be sure to check the ingredients on the label of your protein
Types of Protein Powders
This form of protein is concentrated from a byproduct of the production of
cheese from cow's milk. It comes in three major forms, each of which has a
different bioavailability. Whey protein, in all three forms, is the most
bioavailable form of supplemental protein available. There are some cases of
sensitivity to whey protein, and those who are allergic to milk should avoid
its use. For more information on whey protein, please click here.
Chicken eggs are an excellent source of protein as well as a number of other
vitamins and nutrients. When just the egg whites are used, less nutrition is
available, but it is still an excellent source of complete protein and does
not contain the additional fat. Egg protein is the second most bioavailable
protein source. There are some cases of sensitivity to egg protein, and
those who are allergic should avoid use of this protein supplement.
Rice protein powder consists of brown rice treated with enzymes to remove
the carbohydrate, leaving only the protein behind. This source of protein is
vegan and hypoallergenic. Since it is lower on the food chain it is also
more eco-friendly, and doesn't take such a large environmental footprint to
create. Since it is naturally a little low in the amino acid lysine, rice
protein is often mixed with pea protein to create a more balanced protein
supplement. For more information on rice protein, please click here.
Pea protein powder is created using yellow split peas. Like rice protein,
pea protein is vegan and hypoallergenic, and also has a much more
eco-friendly footprint. In order to balance its amino acid profile, pea
protein is often mixed with rice protein to create a more balanced protein
supplement. For more information on pea protein powder, please click here.
Soy protein powder is extracted from soy beans. It is an inexpensive vegan
protein that offers a complete protein source. In addition to being rich in
protein, soy also contains isoflavones that act as phytoestrogens in the
body. Although this makes them less than promising for body builders, this
can be of great benefit to post menopausal women and others with hormone
imbalances. For more information on soy protein, please click here.
Hemp protein is extracted from hemp seeds and is an eco friendly, and vegan
protein source that provides all 9 essential amino acids. In addition to its
protein content, hemp also contains essential fatty acids (EFAs) and fibre,
both of which are major ingredients in a healthy balanced diet. For more
information on hemp protein, please click here.
This water-grown algae is sometimes considered a complete food. It naturally
contains 60-70% protein as well as a huge number of other nutrients,
vitamins and minerals. It is such a rich source of protein and B12 that it
is often recommended to vegetarians to cover potential dietary gaps. It also
contains chlorophyll, which helps to clear toxins from the body. For more
information on spirulina, please click here.
Protein Availability – Biological Value (BV)
Scientists have developed a measure of a protein's ability to be used by the
body and with this in mind created a scale of bioavailability called
biological value (BV). The value given to a protein source represents the
percentage of the absorbed protein that your body actually uses.
There is a lot of controversy around what form of protein is best, according
to both source and preparation of each type. It is important to note, that
although protein changes shape when it is heated, a process called
"denaturing", so long as some of its bonds remain available for cleaving, it
can still be digested and absorbed. We do not actually absorb whole proteins
as they are too large to pass through our digestive tract, instead we absorb
single amino acids, or small peptides of a few amino acids in a chain. Any
denaturing of proteins does not greatly affect these small building blocks,
and will not change their absorption. Any differences in bioavailability
must come from a blockage of our digestive proteases from properly cutting
the protein up into smaller pieces. This may be impeded by denaturing,
depending on the protein and the degree of damage. For more information on
protein digestion, please click here.
Protein isolates or hydrolyzed protein sources come mostly predigested,
taking the work out of digestion for your body. The body still has to digest
some of the protein chains but in general, the protein is absorbed more
quickly and used more effectively by muscle. These supplements tend to be
costly but are easy for the body to use. Manufacturers claim that most
individuals who have food sensitivities to a particular protein source will
be able to tolerate the amino acids found in isolate powders. Hydrolyzed
supplements like whey concentrates are predigested make amino acid chains
smaller. Egg, rice and pea proteins are not usually altered by manufacturing
techniques to make them more absorbable. Fermenting soy protein makes it
easier to digest.
BCAAs – Branched Chain Amino Acids
This group of amino acids: valine, leucine, and isoleucine are essential
amino acids that contain branched side groups. They have been shown to help
prevent the painful lactic acid build up during strenuous exercise that
causes stiffness the morning after, also known as delayed onset muscle
soreness (DOMS). For more information on BCAA's, please click here.
Single Amino Acids
A number of amino acids can be supplemented individually in powder or
capsule form. Since each amino acid has particular benefits and effects,
please see the individual articles for a better understanding of each one.
Some examples are: lysine, glutamine, glycine, leucine, and histidine.
How can I get more protein?
Protein can be ingested in the diet through a number of different sources
including: meat, dairy, eggs, nuts, legumes, tofu, spirulina, and even
grains like quinoa. Protein supplements can be used for individuals who do
not meet their daily protein requirement through food intake, for
individuals who suffer from blood sugar fluctuations or for athletes who
need to take in large amounts of protein to build muscle more quickly.
Protein supplements can also be used when food is not readily available as a
meal replacement. These meal replacement protein supplements must conform to
government regulations to ensure that the proper amount of vitamins and
minerals are present in the formula.