By Elena Voropay

Protein is not just important, it is essential. Every single cell in your body is is made up of protein. Brain cells, for example, are 10 percent protein. Muscle and red blood cells have as much as 20 percent. Overall, protein is the second largest building material of the human body (preceded only by water) comprising approximately 15% by weight.

To keep your cells alive, you must give them protein all the time. Even though it is not a superb source of energy, like carbohydrates and fats, you need protein and specific amino acids to keep the body alive.

But not all proteins are the same. There are many types of protein including, animal protein, plant protein, human protein amongst a few. IMade of amino acids linked together in long chains, some proteins can be made in the body and some should be consumed through the diet. What differs one protein from another is their amino acid content.

What Are Amino Acids

The body cannot directly use proteins found in food and must break these down into smaller units, known as Amino Acids. Proteins consist of chains of hundreds or thousands of amino acids joined with peptide bonds. When you eat protein-rich foods, the bonds linking the amino acids together are broken by digestive juices and enzymes into isolated amino acids. Only after this process is complete, your cells inside the digestive tract can absorb the nutrients and make them usable for the body.

Think of it as a jigsaw puzzle – protein is the puzzle and amino acids are the pieces that make it. If one or more pieces are missing, you can't see the beauty of the picture. Same thing with protein – unless all amino acids are supplied through the diet, your body cannot make up proteins so imperative in optimal growth of new healthy cells.

"Amino acids are somewhat like letters in the alphabet. If you had only the letter G, all you could write would be a string of Gs: G-G-G-G-G-G-G-G. But with 20 different letters available, you could create poems, songs, or novels. The 20 amino acids can be linked together in an even greater variety of sequences than are possible for letters in a word or words in a sentence. The variety of possible sequences for polypeptide chains is tremendous." -Eleanor Whitney and Sharon Rolfes, "Understanding Nutrition."

Most of the proteins are found in the form of muscles, both skeletal and soft tissue such as the same digestive tract, or your tendons and ligaments.

There are about 28 commonly known amino acids. That's right. Just the 28 aminos are needed to make up to 50 000 proteins in the body, including enzymes and hormones. But to maintain your overall health, you need only 20-23 of the building blocks from your diet and your smart metabolic system will figure out how to make the rest.

From the dietary perspective, these 23 amino acids are classified into three different types: the essential (indispensable) amino acids, the conditionally essential (conditionally dispensable) amino acids, and the non-essential (dispensable) amino acids.

Essential Amino Acids

The nine amino acids which human tissues are unable to make either at all or in adequate amounts must be supplied from the diet. Hence the name - “essential.” These include tryptophan, valine, threonine, isoleucine, leucine, lysine, phenylalanine, methionine, and histidine.

Once you bathed your digestive tract with the nine essentials, the protein job becomes much easier because your body can make additional eleven amino acids from other compounds.  For this reason,  they are termed 'non-essential'. Note, they are not as essential not because they lack importance, but because the body can synthesize them from other amino acids obtained from dietary sources. These include alanine, arginine,  aspartic acid, asparagine, cysteine, glutamic acid, glutamine, glycine, proline, tyrosine and serine.

Conditionally Essential Amino Acids

Then there are 'conditionally essential' amino acids which many may classify as 'non-essential'. These are necessary amino acids, however most people do not have to worry about getting enough of them with foods as they can be made in adequate amounts from other nutrients naturally with the help of enzymes and hormones. With this in mind, most people doesn't mean everybody. Some individuals with certain illnesses or genetic abnormalities either are unable to manufacture these amino acids at all or in amounts they need. For this bunch of metabolically deprived, the 'non-essential' become 'essential'. The conflict in classification makes the terminology a bit tricky, but overall we classify these amino acids as 'conditionally essential'. The trick here is the click – clicking your condition with amino acid needs. It is not rocket science – just look at your condition and figure out whether you may benefit from additional amounts of certain amino acids. The amino acids considered conditionally essential are: arginine, cysteine, glycine, glutamine, tyrosine and proline.

Conditionally essential amino acids deserve a bit more attention because they are especially important during times of stress or injury. At these times, the body is under extreme metabolic demands as it goes through periods of rapid synthesis of cells and tissues. This expedited growth within the body alarms the body that normal dietary intake of complete protein or the eleven essential amino acids alone may not be enough. Conditions where the body cannot synthesize enough protein include young children with growing bodies, post-traumatic and post-surgery patients, people with rare genetic disorders and the ones that live in stressful conditions. It is exactly under these circumstances when conditionally essential amino acids arginine, cysteine, glycine, glutamine, tyrosine and proline become essential.

The body can't store amino acids and will break down it's own protein sources, including healthy muscle and organ tissues, to meet its need for amino acids. If you want to keep your brain, muscles, bones, joints, all internal organs, even blood and lymph performing their functions, you should constantly provide amino acids from a well-balanced diet.

What Do Amino Acids Do

Besides building cells and repairing tissue, amino acids form antibodies to combat invading bacteria and viruses, comprise the enzyme and hormonal systems, build nucleoproteins (RNA & DNA), carry oxygen throughout the body, and are part of all metabolic processes in the body.

It's not the quantity of protein you take, but the quality and ratio of amino acids that keeps the body healthy and stable. The body can make 40,000+ proteins from essential amino acids, but it can only make as much as allowed by the least amino acid present in the body. For example, if one amino acid is only present at the 60% level the assimilation of all amino acids will be limited to that 60% level. This is called rate limiting and it makes balancing amino acid metabolism, using food protein, more difficult.

Best Sources of Amino Acids

The best suppliers of protein with all the essential amino acids are found in animal sources, such as eggs, fish, poultry, meat, seafood, shellfish, milk, cheese and fermented dairy, such as buttermilk, yogurt and cheese. Vegetable proteins are of poorer quality than animal proteins as they do not contain all amino acids to make a protein available in the body. The best Biological Value you can find in vegetable proteins is no greater than 74 you get from soy, compared to 100 in egg, 110 in whey, 93 in milk, 80 in beef or chicken, 75 in fish, 49 in beans and around 40 in wheat. But eating beans with rice or cereal with milk will upgrade the status way above.

If most of the foods you eat come from plants, you can still get all the amino acids from grains, beans (including soy), and legumes. Here is an issue – when you look at nutrient values of any high-protein bread, pasta, cereal, or even beans, you think that these are loaded with all the essential protein blocks. These may be high in protein, but they are not created perfect by nature. Peas, legumes, lentils and beans are limited in amino acids Methionine and Tryptophan, but have plenty of amino acids Isoleucine and Lysine. Whole grains, on the other side, are rich in Methionine and Tryptophan but are limited in Leucine and Isoleucine.

Can you see the connection here? Grains and legumes are a perfect match when it comes to protein! Like a pair of gloves, they are dysfunctional without each other. What is especially interesting about these foods is that when mixed up together, they are become not only high-protein foods, but excellent sources of carbohydrates and fibre which stimulate hormone Insulin, the engine that delivers the nutrients to your all the newborn cells in a slow smooth steady flow, just at the rate they need.

When you combine Leucine-rich beans with Methionine-rich grains, you get a perfect combination of all your nutrient needs. Other excellent combinations are dairy and grains as in cereal with milk or yogurt, toast with peanut butter or cheese, sandwiches with tempeh or tofu and breads made with chickpea or soy flour. If you are looking for the grain source with a balanced set of Essential Amino Acids, quinoa and amaranth are the best.

Seeds and nuts, such as almonds, pistachios, Brazil nuts, pecans, hickory nuts, cashews, hazelnuts, walnuts, pine nuts, chestnuts, and tahini paste from sesame seeds are also great protein additions. Having all of them on the menu is also a superb way to ensure you get a bounty of various vitamins, minerals, antioxidants, phytochemicals, and other biologically important compounds.

Food sources can provide adequate protein intake, it's still fairly difficult to achieve the right amino acid balance for your body's specific needs. There are many conditions that increase the need for amino acids, including lifestyle, diet, stress, illness and trauma. Here you may supplement with Spirulina, Branched-Chain Amino Acids and whey protein powders.