Understanding Protein and Protein Sources

By  Jordan & Kyla Miller

Contributing Writers for  Wake Up World

The most powerful tool to restore and maintain your health and vitality is education.   It is one of the most important tools each of us has in order to understand how food effect’s not only our body, but every aspect of our personal lives.

Protein  plays a key role in helping our bodies achieve optimal health and vitality.

What is Protein?  

Protein is classified as one of three macronutrients (along with carbohydrates and fats) and is an essential part of nutrition. The molecular structure of protein contains carbon, oxygen, hydrogen, and nitrogen, while fats and carbohydrates are made up only of carbon, oxygen, and hydrogen. Protein is second only to water in the body’s physical composition and makes up approximately 20% of our body weight. It is a primary component of our muscles, hair,  nails, skin, eyes, and internal organs – especially the heart (muscle) and brain.

Proteins are made of building blocks called amino acids, of which there are 22. These amino acids combine in unique sequences to make protein and provide 3-dimensional structure. Amino acids are traditionally grouped in two main classes: essential and non-essential. Essential amino acids, of which there are 9, cannot be made by the body (under any circumstance) and must be obtained from the diet. These are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Non-essential amino acids, of which there are 13, can be made by the body from essential amino acids and other co-factors. However, the traditional concept of classifying essential and non-essential amino acids is beginning to be abandoned by some nutritionists and other health care professionals. This is based on the argument that although the body is capable in principle of producing an amino acid, it doesn’t actually mean that it is doing so at any given time. This means that if any of the co-factors, (such as enzymes, vitamins, minerals, amino acids, etc) are missing, the body cannot produce the ‘non-essential’ amino acid. For this reason, there are those who are classifying all amino acids as being conditionally essential.

Why is Protein Needed?

As most are aware, protein is needed for growth and the maintenance of body tissues. As previously mentioned, it makes structural components of the body like muscles,  hair, nails, skin, eyes and internal organs. It is therefore vitally important during childhood, pregnancy and lactation. During times of healing, illness, and after surgery, injuries, burns, or blood loss, we require more protein production to assist in the regeneration of cells and tissues.

Protein is also used in building four necessary substances. Enzymes are protein substances that stimulate a multitude of biochemical reactions. Hemoglobin is an iron-bearing protein that is the key component of red blood cells. It is the molecule that carries oxygen to tissues in the body. Hormones are also formed from protein. Two of the primary protein  hormones  are insulin, which regulates blood sugar, and thyroid hormone, which regulates our metabolic rate. Finally, protein plays a major role in our immunity when it initiates the formation of antibodies in response to foreign intruders (called antigens) in the body. A specific antibody is formed in order to bind with a specific antigen and inactivate it, contributing to a strong and healthy immune system.

Proteins help to keep the correct amount of water in cells. They also help to maintain our body’s essential sodium and potassium balance, responsible for normal muscle and nerve cell formation. This balance also aids the  heart, lungs and nervous system to function properly.

Proteins have the ability to act as buffers and can help to normalize the acid-alkaline balance in the body. It does this by helping to eliminate excess hydrogen ions, which are a part of acids. If functioning properly, the pH of the blood is kept near constant at about 7.4.

Protein supplies 4 calories per gram and, in extreme circumstances, can be used as energy. The body will first use carbohydrates and fats for energy, but if these sources are low, it will burn dietary protein. If dietary protein is also low, the body will break down its own tissue proteins (muscles) to meet its energy needs.

Protein Requirements

What may be even more important than the amount of protein consumed, is the quality of protein consumed. There are two methods that have been devised to measure the quality of protein in foods. The first is called biological value (BV). This measurement looks at the amount of nitrogen that is released from protein and absorbed into the body – a great indicator of protein status, since it is the only macronutrient that contains nitrogen. The second measurement is called net protein utilization (NPU). It is measure the same way as BV, but it also takes into account the how readily the foods are digested and how efficiently the body can use the proteins. Those foods with lower digestibility can be improved by methods such as soaking, sprouting and fermenting.

The Recommended Daily Average (RDA) of protein for adult males and females over the age of 19, in the U.S., is 0.8 grams per kilogram of ideal body weight. These requirements increase by 25 grams daily during pregnancy and lactation. They also increase during stages of growth and activity.

These requirements are based on maintaining a positive nitrogen balance in children and an even-to-positive balance in adults. As previously mention, protein is the nitrogen-containing nutrient. It is the daily breaking down and building up of protein that determines the nitrogen balance in the body. In adults, a positive nitrogen balance can lead to protein excess, whereas a negative nitrogen balance can result in protein deficiency.

How is Protein Digested and Metabolized?

Since the quality and digestibility of a protein are important in ensuring adequate amounts of protein, it is vital to understand how protein is digested and metabolized.

Protein digestion begins in the mouth. Chewing separates protein and prepares it to be broken down further in the stomach. In the stomach, enzymes and hydrochloric acid (HCl) breakdown proteins into long-chain polypeptides (amino acid chains). These are then transferred to the first part of the small intestine, called the duodenum, where pancreatic enzymes turn long-chain polypeptides into shorter-chain polypeptides – called tripeptides and dipeptides. Farther along the small intestine, amino peptidases turn tripeptides and dipeptides into single amino acids, which are actively transported through the intestinal wall and carried to the liver. The liver is the main site and regulator of amino acid metabolism.

How to Attain Adequate Protein

A balanced diet is extremely important in order to ensure significant levels of all essential amino acids are consumed. This is why a diet containing a variety of wholesome foods is important. Each food has a different ratio of amino acids. It is therefore important to have an understanding of protein composition and apply it in our diet.

Complete proteins are foodstuffs that contain, at least, all 9 essential amino acids.   Sources of complete proteins include: meat (beef, bison, pork, lamb), fish and poultry (chicken, turkey), dairy (milk, cheese, yogurt, kefir) and eggs. Incomplete proteins are foodstuffs that lack one or more of the 9 essential amino acids. Sources of incomplete proteins, when considered singularly, include: vegetables, grains, legumes, nuts and seeds.

Based on this information, one might reason that in order to attain adequate protein, it makes sense to only consume foods that are complete proteins. However, there are concerns that over-consumption of protein foods, particularly meat and milk, contribute to some major illnesses; so we may not wish to consume these foods daily or even at all.

What if we are a vegetarian or vegan? Although most plant source proteins do not contain all of the essential amino acids individually, they can be combined over a 1 to 2 day period in order to yield complete proteins. This takes knowledge and advanced preparation. In order to ensure complete protein intake, the following combinations should be used: grains and beans/legumes, grains and nuts, grains and seeds, grains and green leafy vegetables, and/or grains and soy. Additionally, there are a few vegan sources of complete proteins. These include quinoa, soy, spirulina, hemp, chia and sprouted brown rice.

Is Protein Excess Possible?

There is definite concern that the industrialized countries are over-consuming protein, especially from meat and dairy foods. If fact, the U.S. RDA guidelines of 0.8 grams of protein per kilogram of ideal weight are high compared to the guidelines of 0.45 grams recommended by the World Health Organization.

Excess protein, especially if attained from meat and dairy, can lead to a diet high in saturated fats – resulting in degenerative conditions such as cardiovascular disease. These foods also tend to be more acidic and so minerals, such as calcium attain from bones, are used to neutralize these acids and restore the body’s pH balance. If enough calcium is required, this could lead to conditions such as osteoporosis and arthritis.

Is Protein Deficiency Risky?

The name for protein deficiency disease is kwashiorkor, a wasting disease that in its severe state leads to death. This disease is most common in impoverished and starving populations. Although protein deficiency does not seem like a real threat in Western society, it is definitely possible.

Faulty eating habits, yo-yo dieting, low calorie diets, and inadequate protein sources can all lead to some form of protein deficiency. Additionally, adequate daily protein can still lead to deficiency if digestion is poor.
Symptoms of protein deficiency include weight loss, edema, nausea and dizziness, poor concentration, general overall weakness, dull loose and falling out hair, anemia, decreased immunity, premature aging, muscle wasting, low hormone levels, etc.

In Summary

Whether you eat animal or plant based foods, the quality of protein is just as important as the quantity. Optimal digestion also plays a major role in the metabolism and use of dietary protein.

By eating a variety of freshly balanced foods and maintaining a healthy digestive system, you will be sure to attain adequate protein necessary for optimal body composition and overall health and vitality!

Your question: Where do you get your protein? (post your comments below)

Article Sources:

1. Haas, Elson M. M.D. and   Levin, Buck, PhD, RD. Staying Healthy with Nutrition.

    21st Century Edition.   Crown Publishing Group. 2006

2. Marieb, Elaine N. R.N., PhD. Essentials of Human Anatomy & Physiology.

    9th Edition.   Pearson Benjamin 2009.

3. Wolters Kluwer.   Pathophysiology made Incredibly Visual.

    2nd Edition.   Lippincott Williams & Wilkins 2012.

About the Authors

Jordan & Kyla  are passionate about health; together, they have overcome many illnesses through dietary and lifestyle changes, and the art of practicing a positive mindset daily. Kyla is currently studying to become a Registered Holistic Nutritionist and Reiki Master, and Jordan is currently learning about traditional North American medicinal herbs, in hopes of becoming a Certified Herbalist.  For more information, please visit the following sites;  guidinginstincts.com,  Facebook,  Twitter,  Google+, or  Pinterest


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