Introduction
The word 
seems to be popping up everywhere these days. 
, in its simplest form, it means something we can’t live without and protein is definitely one of those things. Protein occupies pride of place on a long list of nutrients that are to our health ( fatty acids, amino acids, etc.). Once consumed, it is broken down into other working parts, and in concert with others, helps the body build and repair most of the components that keep us running smoothly every day.
Proteins play an important part in every cell membrane in the body. Your hair, skin, and nails would start to look quite shabby without adequate protein in your diet. Your muscle tissue would begin to decline without adequate protein intake. And in actual fact, bone contains quite a bit of protein in the rubbery inner structure and bone marrow. The hemoglobin in your red blood cells is a protein that carries oxygen to all parts of your body and lipoproteins are particles in your plasma which ferry cholesterol to where it’s needed in the body. Want to reach for the phone? In order to move the muscles required to complete this task, your nerve cells send messages back and forth to each other in the form of neurotransmitters which are made from building blocks of…you guessed it…proteins.
We are spoiled for choice when it comes to protein as it exists in many different animal and plant-based forms. Once consumed, protein is broken down in its component parts called amino acids. Amino acids are reassembled into many new and specialized elements, including things like enzymes which perform unique tasks such as digesting food. In this case, the enzymes require the help of specific vitamins and minerals to complete the job. That’s why your body needs you to eat a balanced diet that provides vitamins, minerals, and proteins every day.
What Are Proteins?
Out of all the organic molecules in your body, proteins have the most varied roles to play. Some are in the construction business, others work in operations, and still more in removal services. Every protein is made up of amino acids. Think of a long strand of knotted pearls. This is very similar to the makeup of a protein molecule, with each amino acid being a pearl in the strand and each knot a peptide bond. Proteins are also referred to as polypeptides because of the multiple peptide bonds that hold the amino acids together to form a protein. There are approximately 20 common amino acids which rotate and combine to make up proteins. And the word “common” is appropriately used to describe them because all amino acids are made up of one amino group and one acid group. But for a single group of atoms called their R-group, every amino acid is identical. It’s actually the sequence in which the amino acids are combined that determines the type of protein molecule that is made.
Amino acids are the building blocks of proteins. All amino acids have a central, or “alpha” carbon, to which are bonded 4 groups: a hydrogen group, an amino group, an acid group, and the R-group.
The Breakdown of Protein Molecules
The amino acids in protein molecules are held together by peptide bonds; a chemical bond formed between two amino acids when the acid group of one reacts with the amino group of the other.
Protease, or proteinases as they are also called, are a digestive enzyme group which break the peptide bonds in the protein in the foods we eat to liberate the amino acids needed by the body. This process is accomplished through hydrolysis, which literally means “chemical combination of water with a salt to form an acid and a base; dissolution of a bond by reaction with water”.1 Protease comes together with hydrochloric acid to break down large protein molecules, which in turn allows your small intestine to absorb the individual amino acids through the walls and into your bloodstream.
What Are Amino Acids Used For?
Like a jeweler might take pearls from a strand on a necklace to create a pearl bracelet, your body, following genetic instructions, takes the separate amino acids and strings them back together into the proteins it needs, such as enzymes and hormones which regulate bodily functions and activate vitamins and other nutrients. Some chains will be short, like the bracelet. Others are long and complex, and fold over and over themselves, like origami. It’s the ultimate in recycling!
Essential , Non-Essential, and Conditional Amino Acids
| Twenty or so amino acids are required for human life to exist. Your body can produce some on its own but others it needs to obtain solely from the foods we eat. Amino acids which cannot be created by our bodies are classified as essential. All the others are classified as either non-essential or conditional (not essential, but still necessary). To view the complete list, CLICK HERE. Because the body doesn’t store amino acids, as it does fats or carbohydrates, it needs a daily supply of amino acids to make new proteins. | Histidine* Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine |
Additional essential amino acids for infants and growing children include cysteine, tyrosine, and arginine.
Alanine Arginine* Aspartate Cysteine* Glutamate Glutamine* Glycine* Proline* Serine* Tyrosine* Asparagine* Selenocysteine | *Falling under the “conditionally essential” heading are the following – arginine, cysteine, asparagine, glycine, glutamine, histidine, proline, serine, tyrosine. Now, I know you’re saying, “wait a minute here, how can one amino acid be on both lists”? Good question; here’s the answer…the term “conditionally essential” means they are not normally required in the diet but must be supplied to specific groups of people (usually people living with illnesses or chronic stress) that do not synthesize them in adequate amounts.
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Complete and Incomplete Proteins
Traditionally, foods were classified as either complete or incomplete proteins based on the amino acids they contained. However, now varying opinions in the health community on this definition blur the lines. A complete protein contains all the essential amino acids. Conversely, an incomplete protein lacks a few of the essential amino acids. Eating a wide variety of foods, or combining two foods which are, in themselves, incomplete to make a complete protein (such as rice and beans), is a way of ensuring your body gets what it needs every day.
Your Daily Protein Intake
The recommended daily allowance (RDA) or intake (RDI) for adults is between 10% and 30% of your total daily caloric intake. To ascertain your personal RDA, first determine your basil metabolic rate (BMR) + total calories which your daily activities burn. This gives you an estimate of how many calories you need to maintain your current weight. Next, figure out what percentage of your diet should come from protein by taking into account your age, physical health, gender, and activity levels. Once you’ve determined your desired percentage of protein (higher end of scale vs. lower end), multiply that by the total number of calories for the day. For example:
1800 x 10% = 180 calories from protein.
180/4 = 45 grams of protein per day.
Sedentary people should stick to the lower end of the scale (around 10%), while pregnant, convalescing, or active people can consume more protein to support muscle growth and recovery, and to prevent muscle loss. In essence, the more you exercise, the greater your protein needs will be. The American College of Sports Medicine recommends that endurance and strength-training athletes should have between 0.5 and 0.8 grams of protein per pound of body weight for the best performance and health.Plant Protein, Animal Protein
Animal proteins tend to be complete proteins. However, the drawback to this type of protein is the saturated fats you can run into with meats. And for some of our even more sensitive readers, there’s the issue of GMO’s and antibiotics. If you want to include protein from animal sources, try to shake up your selections by rotating through choices like wild salmon, lean steak, skinless chicken, halibut or tuna, and maybe even consider a meatless Monday or meat alternative.
On the flipside, there are plant proteins which tend to be incomplete unless combined with each other to form a complete protein. Having said that, unless you’re buying organic, you’re dealing with pesticides and fertilizers and knowing which plant combinations make a complete protein. So what’s a body to do?
The answer is to establish a good balance of protein sources on your plate and this is easily accomplished if you eat a wide variety of healthy foods every day. It’s not necessary to consume a complete protein at every meal so long as you are accumulating protein from your food during the day. For those who are more interested in specifics, use the following table as a reference. After a while source-combining will become second nature. Any item from Group #1 can be combined with any item from one of the three groups below to make a complete protein.
Whole grain beds: rye, wheat, oat, rice, spelt, quinoa, long grain brown rice, whole wheat products and whole grain cereals, pasta, spaghetti, noodles | ||
All Peas, Beans & LentilsAll dried beans and peas including black, kidney, pinto, black-eyed peas, runner, chick peas, sweet green peas, baked beans, bean sprouts, edamame | Leafy Green & CruciferousArugula, bok choy, broccoli, Brussels sprouts, cabbage, cauliflower, Chinese cabbage, kale, turnips, mustard greens, collard greens, spinach, romaine, curly endive, arugula, chard | Nuts & SeedsAlmonds, pumpkin seeds, walnuts, cashews, peanuts, sunflower seeds, hazelnuts, pecans, sesame seeds, chia seeds |
From WebND – Plant Protein Combinations
Table of Protein in Common Foods
Now that you understand how to combine incomplete proteins to ensure most of what you eat is complete, here’s a table to help you recognize how much protein is in some common foods. If there’s something not on this list that you commonly include with your meals, a quick search of the Internet will give you the protein content, or the Nutrition Chart on the package will give you the per-serving protein content of the product.
3.5 ounces or 100 grams per serving, unless otherwise stated
| Beef Hamburger patty, lean, 4 oz. = 28g Steak, lean, 6 oz. = 42g *Most cuts of beef contain 7g/ounce | Chicken Breast= 30g Thigh, average size = 10g Drumstick, average size = 11g Wing = 6g Ground chicken, lean, 4oz. = 35g | Fish Tuna, canned in water = 23g Cod, baked. = 21g Halibut = approx. 27g Salmon = 22g Tilapia = 27g Lobster = 26g Shrimp, crab = 29g | Pork Pork chop = 22g Pork loin, 4oz. = 29g Ham, 3 oz. = 19g Ground pork, lean, 3 oz. cooked = 22g |
| Nuts, Grains and Seeds – Almonds, 1 oz., 23 whole nuts = 6 grams, Brazil nuts, 1 oz., 6 whole nuts = 4 grams, Cashews, 1 oz., unsalted = 5 grams, Hazelnuts, 1 oz., 21 whole nuts = 4 grams, Oats = 16 grams, Pecans, 1 oz., 19 halves = 2.6 grams, Pistachios, 1 oz., dry roasted = 6 grams, Quinoa, cooked = 4.4 grams, Spelt, cooked = 5.5 grams, Sunflower seeds, 1 oz., dry roasted, no salt = 5.4 grams, Pumpkin seeds, 1 oz. = 8 grams, Flax seeds, 1 tbsp., raw = 1.88 grams, Walnuts, 14 halves = 4.32 grams | |||
| Vegetables – Asparagus, 6 spears = 2.16 grams, Beets, ½ cup, cooked = 1.4 grams, Bok Choy, 1 cup, cooked = 2.65 grams, Broccoli, ½ cup, cooked = 1.86 grams, Brussels sprouts, 1 cup, cooked = 3.98 grams, Butternut squash, 1 cup, cooked, = 1.84 grams, Cabbage, ½ cup, cooked = 1 gram, Carrots, ½ cup, cooked = 0.6 grams, Cauliflower, ½ cup, cooked = 1.14 grams, Corn, 1 large ear = 4 grams, French beans, 1 cup, cooked = 12.5 grams, Lima beans, 1 cup, cooked = 14.6 grams, Parsnip, 1 cup, cooked = 2 grams, Peas, 1 cup, cooked = 8.58 grams, Potatoes, 1 medium baked = 4.33 grams, Spinach, 1 cup, raw = 0.9 grams. Spirulina, 1 cup dried = 64.37 grams, Swiss chard, 1 cup, cooked = 3.29 grams | |||
Protein Powders, Not All Are Created Equal
Protein powders are becoming very popular with the general public and aren’t just for body builders any more. 
Protein powder is a great addition to your daily smoothie if you think you’re not going to get your daily RDA of protein from the foods you’ll consume during the day. They’re also great as supplements for picky eaters, seniors, and people recovering from an illness. Protein also plays a crucial role in brain functions such as moods, concentration, memory and learning. Amino acids from proteins are used to make neurotransmitters; components which help your brain communicate and send out signals to your body. Neurotransmitters are absolutely essential to brain health.
Not all protein powders are created equal, nor are they all complete proteins. (Proteins are dubbed “complete” when they contain all of the essential amino acids the human body needs but can’t produce on its own.) Some protein powders are not tolerated as well as others due to their constituent parts. So, it helps to know the difference before making a decision on which one to use. Even then, it is suggested that you mix them up now and again so that you’re not always using one single type of protein powder. Confused yet? Let’s go on to look at each one.
Soy – soybean derivative, not as easily absorbed by the body, plant-based, ideal for vegetarians & lactose-intolerant people, contains less saturated fat than whey, contains all essential amino acids which means it is considered to be a “complete” protein, superior choice for heart health, main dietary source of isoflavones (phytoestrogenic compounds found in plants) which support healthy cholesterol levels, reduce the risk of heart disease, protect the prostate, improve bone health, can be used to relieve menopausal complaints, soy contains decent amount of omega-3’s (also good for heart health), does not absorb as quickly as hemp or whey, choose soy protein made from fermented soy (Prairie Naturals).
Whey – dairy; a cow’s milk derivative, contains lactose, 3 types of whey: concentrate, isolate*, and hydrolysates**, human body absorbs whey better than soy, contains all essential amino acids, quickly absorbed by the body, reaches muscle tissue quickly making it a good choice for pre and post-workout muscle performance, recovery, and repair, contains high levels of the amino acid cysteine (important for nails, skin, hair, collagen production, powerful antioxidant, chelates heavy metals and aids in iron absorption).
*Isolate – created by removing why protein from milk, drying it, then removing the non-protein components, including fat and milk sugar lactose.
**Hydrolysate – a mixture of amino acids prepared by splitting a protein with acid, alkali, or enzyme. Such preparations provide the nutritive equivalent of the original material in the form of its constituent amino acids and are used as nutrient and fluid replenishers in special diets or for patients unable to take ordinary food proteins.
Hemp – plant-based, is a complete high-quality protein even though it is plant-based*, derived from hemp seeds, good choice for vegetarians or the lactose-intolerant, superior choice for heart health, easily digested (more so than soy), high in fiber, high omega-3 and 6 content in 1:3 ratio (good for lowering blood pressure and cholesterol), better source of EFA’s than flax, rich in heart-healthy “good” fats, better choice for those with peanut or soy allergies, gluten-free.
*The U.S. Department of Agriculture calls hemp protein “high quality”…the hemp seed is that extremely rare plant-based nutritional source that offers a complete protein. 2
Rice – plant-based, particularly high in leucine, valine and methionine as compared to whey and soy, supplement is made from brown rice, easily digested, lactose-free, gluten-free, possibility of it tasting more chalky than other protein powders, allergen-free, lower in calories (unless heavily flavoured), incomplete protein (unless otherwise stated; see Prairie Naturals Organic Rice Protein).
Protein and Plant-Based Diets
Protein and My Body
Egg – digested quickly, highly digestible and bioavailable (the higher the bioavailability of a food, the quicker nutrients can be extracted from them and put into use by your body), low fat, lactose free, low-carb, low-sodium, rich in essential amino acids, higher percentage is used-less is wasted by the body (good before a workout), comes from the egg white so also low in cholesterol but lacking in the nutrients that a whole egg contains (in this case, balance out your diet with lean meats and legumes to provide additional vitamins and minerals that your body needs).
Vegetarian, vegan (strict-vegetarian; no meat, fish, eggs or dairy), lacto-ovo-vegetarian (includes dairy and eggs), pesco-vegetarians (fish, diary, eggs), semi-vegetarians…all are classified as plant-based diets, but some with a little more thrown into the mix than just salads. How do people who eat these types of diets get enough protein? As a matter of fact, some very well-respected authoritative bodies, such as the Food and Nutrition Board, Institute of Medicine profess that “Only one calorie out of every ten we take in needs to come from protein.” The trick is to take in an appropriate amount of calories from a wide variety of foods throughout the day. To see how easy it is to take in your RDA of protein from plant-based sources, CLICK HERE.
According to the Harvard School of Public Health website, “The most solid connection between protein and health has to do with allergies. Proteins in food and the environment are responsible for these overreactions of the immune system.” When it comes to protein and chronic diseases, we now know that protein consumption has to be over a longer period of time, and of an exaggerated amount, before it starts doing harm to the body. In fact, it is possible that eating more protein, especially vegetable protein, while cutting back on easily digested carbohydrates may benefit the heart.” 3
Protein and Your Weight
Animal proteins such as chicken, beef, and fish don’t digest as quickly as some carbohydrates and move more slowly from the stomach to the intestine, leaving you feeling fuller longer. And as for averting cravings, protein has a gentle, steadying affect on your blood sugar levels. Having a chicken breast with salad for lunch means you won’t be riding the sugar rollercoaster by 2 pm. And because protein takes longer to digest, the body uses more energy to digest it than it would use to digest fats or carbohydrates. But don’t make the mistake of eating protein to the exclusion of all else because the nutrients in other foods are essential to the break down and reassembling of protein into other vital elements your body needs.
Too much of a good thing…Breaking down proteins requires more water than carbohydrates or fats. Any diet with a protein consumption of more than 35% of your daily caloric intake can create a buildup in your body of substances called ketones. An overload of ketones in the body, called ketosis, throws your kidneys into overdrive in order to bring the body back into a state of homeostasis, or balance. Significant amounts of water are rerouted to this cause, putting you at risk of dehydration, especially if you’re an exercise fanatic, or if you’re not consuming enough water every day. This extra effort places your kidneys and heart under considerable strain only to show up on the scale as water loss.
The Soy Storm
Soy is one source of protein that has been getting a lot of attention in recent years and the two schools of thought on this topic are highly polarized. Soy protein contains a high concentration of phytoestrogens called isoflavones. Early studies showed that the benefits of eating soy included lower LDL cholesterol and triglyceride numbers. Updated studies, however, show that these numbers aren’t as accurate as first thought but that there still is merit and numerous health benefits to including soy protein in your diet. Opponents of the pro-soy camp believe that plant-based estrogen-like substances such as isoflavones can actually cause damage to the body because of their ability to mimic estrogen. Specific concerns center around the issue of breast cancer and the association isoflavones may have with the stimulation and growth of breast cancer cells. The definitive word is not out yet on this issue. As each person’s physical makeup and tolerances are different, it’s best to discuss this with your primary health care provider if you are concerned about consuming soy protein.
Nuts to Heart Disease
One surprising finding from nutrition research is that people who regularly eat nuts are less likely to have heart attacks or die from heart disease than those who rarely eat them. Several of the largest cohort studies, including the Adventist Study, the Iowa Women’s Health Study, the Nurses’ Health Study, and the Physicians’ Health Study have shown a consistent 30 percent to 50 percent lower risk of myocardial infarction, sudden cardiac death, or cardiovascular disease associated with eating nuts several times a week. In fact, the FDA now allows some nuts and foods made with them to carry this claim: “Eating a diet that includes one ounce of nuts daily can reduce your risk of heart disease.” 4
It could be that unsaturated fats such as omega-3’s contained in some nuts help lower LDL, raise HDL, and prevent blood clots. Another benefit to nuts is that they contain the amino acid arginine which contributes to the relaxation of constricted blood vessels, allowing blood to flow more easily. In addition, they’re packed with other healthy nutrients needed to maintain optimum health throughout the body.
Protein Deficiency in Children and Adults
Protein deficiency is rarely seen in North America thanks to our ability to access a wide variety of protein sources. However, sometimes intestinal problems and certain liver and kidney conditions can contribute to a protein deficiency. Symptoms of a deficiency include irritability, fatigue, and muscle wasting as the body turns to its own muscles as a source of protein. In children, growth rates and development begin to slow. Other symptoms include weight loss, weakness, frequent infections (as the immune system becomes ineffective), and fluid retention.
The Vegetarian Resource Group
Nutrient Values of Nuts, Grains and Seeds
Nutrient Value of Vegetables
How to Meet Your Protein Needs without Meat
References:
1. Barron’s Dictionary of Medical Terms, Fourth Edition
2. The Facts About Hemp Protein
3. The Nutrition Source, Protein, Moving Closer to Center Stage, Harvard School of Public Health
4. The Nutrition Source, Nuts for the Heart, Harvard School of Public Health
Essentials of Human Anatomy & Physiology, Seventh Edition, Elaine N. Marieb