8 Nutrients to Know – Proteins


Leon Martinez Gist; San Juana Cruz; and Ana PIna Vega

Introduction – Proteins

Protein is well known as being the main ingredient bodybuilders use in their shakes to be so strong; however, this nutrient has many more functionalities going for it than just workout competitions. Proteins are made of amino acids and are incredibly important for the well being of the body. Proteins can aid the body in numerous ways and are critical for many functions, making them so important and interesting. This chapter will give some insight into the nutrient protein, why it is important, how to attain it, and more.

Amino Acids

There are plenty of unique proteins and amino acids; however, humans only use 20 amino acids to create the proteins needed. This graph shows which need to be obtained through diet and which the body can produce all on its own. 9 amino acids are considered essential amino acids because they need to be obtained in the diet while the rest can be created autonomously. However, some non-essential amino acids can become essential, creating conditionally essential amino acids; these exist when the body is, for some reason, not producing enough of the particular amino acid.

– Lets see if the thinking caps are on: 











All the info about amino acids begs the question, how exactly are proteins made? Which leads into the next learning phase.


How to Make Proteins 101

Proteins are formed by combining amino acids, which can form a variety of bonds called peptide bonds. This is why it is important to incorporate meals with all amino acids or consume the essential amino acids if you are not faced with a conditionally essential acid. Once these bonds are formed, they begin to take shape determined by the different amino acids in the peptide bonds. The process of protein synthesis can be especially convoluted – as well as the way proteins are shaped. Their structures may sound familiar to anyone who has taken a biology class, and there are four levels. These four levels consist of the primary structure, which is essentially the order in which the aforementioned amino acids are arranged. The secondary level is when the amino acid arrangement begins to take on a shape and either take on a form known as an alpha-helix or a beta-pleated sheet – in this stage; the immature protein takes on a 3D shape. The third form is called the tertiary structure and regards the 3D arrangement of the protein, which is quite interesting in how this shape is welded together. To simplify – the help of hydrophobic interactions fold the alpha-helix or beta-pleated sheet, and hydrogen bonding glues this structure together. The fourth level is called the quaternary structure (fun to pronounce), which not all proteins have – in this structure, the protein subunits come together with their own structures to form the quaternary structure – keep in mind shape determines function, so the shape of the structure will direct the physiological workload even if different subunits are in the protein.

The video above gives a more in-depth explanation of how this nutrient that is so very important is created in the very beginning stages during a process called protein synthesis.


How the body breaks down proteins.

Proteins in food are chewed and moistened with saliva to ease swallowing for it to be easier to digest  Once inside the stomach, hydrochloric acid denatures the protein strands / Pepsin breaks down proteins into single amino acids and shorter polypeptides These amino acids and polypeptides travel to the small intestine to further digestion and absorption.

Once the polypeptides reach the small intestine, the pancreas and small intestine secure enzymes digest them into oligopeptides, tripeptides, dipeptides, and single amino acids, proteases the enzymes that digest polypeptides. Cells in the wall of the small intestine absorb single amino acids, dipeptides, and tripeptides. Peptides, which are enzymes located in the intestinal cells, break the dipeptides and tripeptides into single amino acids. Amino acids are transported to the liver where they are converted to glucose or fat, and it is used for energy to build new proteins or transported to cells needed. Meat and Diary are highly digestible animal proteins. Grains and some vegetables are less digestible.


Why do we need Proteins? 

Proteins in the body are broken down, so we need to replace them with new proteins. Proteins help with cell growth. Take an embryo; for example, it needs protein to develop and grow. A newborn baby has about 10 trillion body cells! Red blood cells live for about 4 months and get replaced by new cells produced in the bone marrow. Proteins also act as hormones. Here is an example: thyroid hormone regulates many aspects of metabolism, acid, and insulin. Then it acts as the cell membrane to facilitate the transport of glucose into cells.

Protein helps maintain fluid and electrolyte balance. When your protein intake is deficient, you can have Edema, which is a serious disorder in which fluids build up in the body’s tissue spaces, causing fluid imbalances and a swollen appearance. A proper balance of sodium and potassium are examples of electrolytes. This is accomplished by protein molecules that help transport substances throughout the body and across cell membranes.

Some consequences of low protein intake:

  • Muscle weakness
  • Spams
  • Kidney Failure
  • Even sometimes in certain bad conditions can lead to death.
  • Skin, hair, and nail problems
  • Fatty Liver
  • Decreased energy

Other Roles of Protein:

Protein works as antibodies, antibodies are defensive proteins of the immune system, and their production is prompted by bacteria, viruses, toxins, and allergens. They transport and store nutrients by carrying iron in the blood and stored in the liver. The amino acids from protein can make neurotransmitters, which are chemical messengers that transmit messages from one nerve cell to another. Examples of neurotransmitters are epinephrine and norepinephrine; they stimulate the sympathetic nervous system, and melatonin, which plays a role in regulating sleep.

How much protein should we eat?

Per RDA, recommended energy from protein is 10% to 35% in the total intake.

Protein needs are higher for children, adolescents, and pregnant lactating women because more protein is needed during growth and development. Positive Balance occurs when nitrogen is greater than excretion. This state indicates that the body retains or adds protein and occurs during periods of growth, pregnancy, recovery from illness, and protein deficiency. Negative nitrogen balance occurs when you have a severe illness, infections, high fever, serious burns, or injuries that cause a lot of blood loss. People in these conditions require a higher intake of protein in their meals. Nitrogen Balance is when nitrogen intake equals nitrogen excretion. People in these conditions, their protein intake is sufficient, and they are healthy adults who are not pregnant.

Group Protein intake ( grams per Kilo body weight)
Sedentary adults 0.8
Nonvegetarian endurance athletes 1.2 to 1.4
Nonvegetarian strength athletes 1.2 to 1.7
Vegetarian endurance athletes 1.3 to 1.5
Vegetarian strength athletes 1.3 to 1.8








Eating protein is important for your body, but if you take in more than you should, there are some side effects. Protein is found in many foods with saturated fat, which contributes to high cholesterol levels, and that can cause heart diseases or stroke. Consuming a meat-based diet with very few plant-based foods usually leads to low fiber intake. Fiber is a type of carbohydrate, and it plays an important role in digestion. This can cause some constipation. Also, people with Kidney disease who eat a high protein diet can be harmed because the kidneys don’t work well; getting rid of waste products can worsen kidney function. In healthy people, it is shown that there is a risk if you eat a lot of protein, but it is important to drink a lot of water.



Choosing Healthful Proteins

Eating protein-rich foods encourages an adequate intake level of protein in the body to support its functions to work properly and efficiently. These foods include legumes, nuts, poultry, soy products, fish, seeds, dairy products, and eggs. Protein shakes, powders, and supplements are a good alternative to maintain ab adequate intake of protein.

Here is a link for more information about protein, the types of protein-rich foods there are, and how to meet protein needs: https://www.betterhealth.vic.gov.au/health/healthyliving/protein.

Can a vegetarian diet provide adequate protein?

Vegetarianism follows a restricted diet that consists of plant-based foods such as vegetables, fruits, grains, and nuts. It has become more common in society as people become more responsible for themselves and their eating habits, giving vegetarianism a try as a lifestyle choice. Although protein intake may be limited, it is still available through certain foods in different vegetarian diets.

The following are seven types of vegetarian diets:

  • Flexitarian (Semi-Vegetarian) – plant-based diet includes meats, poultry, and fish from time to time.
  • Pescatarian – plant-based diet with the inclusion of seafood and sometimes dairy and eggs if chosen.
  • Lacto-ovo Vegetarian – plant-based diet with the inclusion of dairy and eggs.
  • Lacto Vegetarian – plant-based diet with the inclusion of dairy products.
  • Ovo Vegetarian – plant-based diet with the inclusion of eggs and products that contain eggs.
  • Pollo Vegetarian – plant-based diet includes poultry foods such as chicken, turkey, and duck. Can choose to incorporate seafood, eggs, and dairy into diet.
  • Vegan- strictly plant-based diet, not a single animal product. Foods include vegetables, nuts, grains, fruits, and legumes.

Why do people choose vegetarianism?

People choose to become vegetarian to make a difference in the environment, health benefits, and due to their religious and ethical beliefs and food-safety concerns.

By becoming vegetarian, people can reduce the negative impacts of meat production on the environment, such as pollution, global warming, and deforestation. Also, by following a vegetarian diet, people can reduce the risks of high blood pressure, type 2 diabetes, heart disease, and some cancers increasing their health and well-being overall.

Another reason would be that some religions do not allow the consumption of animals to direct them towards the vegetarian diet and how some people believe it is morally wrong to eat animals and animal products such as eggs and dairy products. The way meat is handled and the risk of contamination associated with it is a safety and health concern to those who want to prevent the illnesses resulting from the practice. People prefer to stay away and choose to become a vegetarian.

The health benefits of following a vegetarian diet are why people choose to practice vegetarianism as it can reduce many chronic diseases. The following are the health benefits of following a vegetarian diet:

  • Reduced risk for obesity and type 2 diabetes due to reduced intake of saturated fat and total energy.
  • Lower blood pressure due to a higher intake of fruits and vegetables and regular exercise.
  • Reduced risk for heart disease due to higher dietary fiber and antioxidant vitamins, minerals, and phytochemicals.
  • Fewer digestive problems such as constipation and diverticular disease, due to high fiber intake.
  • Reduced risk of some cancers such as colorectal cancer and reducing carcinogens that are formed when cooking meat.
  • Reduced risk for kidney stones and gallstones by consuming higher intakes of legumes and vegetable proteins such as soy.

The potential challenges of vegetarianism are the nutrient deficiencies in protein, calcium, zinc, iron, iodine, vitamins B, B12, and D.  As well as experiencing symptoms such as fatigue, weakness, anemia, bone loss, and thyroid issues. Limiting one’s diet from these important nutrients will begin to impact health and well-being negativelyFollowing one of the more flexible vegetarian diets will provide sufficient nutrients, although taking supplements and multivitamins may be a substitute.  



What disorders are related to protein intake? 

Protein deficiency can lead to life-threatening diseases as a result of malnutrition. Low protein intake can increase the risk of illnesses, infections, and even death due to protein-energy malnutrition, not consuming enough total energy. Two associated diseases are Marasmus and Kwashiorkor.




Marasmus is a disease caused by inadequate intakes of protein, energy, and other nutrients, being protein-energy malnutrition. Those who develop the disease will slowly starve to death with an appearance of “skin and bones” due to their body tissues (such as muscles) wasting away. Marasmus is most common in young children (6 to 8 months of age) who are poor, living in unsuitable and unstable conditions, and are severely undernourished.

Marasmus affects an individual by the following:

  • Wasting and weakening of muscles, including the heart muscle
  • Stunted brain development and learning impairment
  • Stunted physical growth and development
  • Anemia (abnormally low levels of hemoglobin in the blood)
  • Severely weakened immune system.
  • Fluid and electrolyte imbalances

Treating Marasmus primarily begins by gaining fluid and electrolyte balances and then providing the individual with proteins and carbohydrates once the body has stabilized. Once protein levels in the blood begin to improve, fat will be introduced so that the body can metabolize it efficiently. When left untreated, Marasmus will cause infection, heart failure, and death from dehydration.


Kwashiorkor is a protein-energy malnutrition disease that occurs to toddlers and infants (1 to 3 years old) in developing countries accustomed to food other than their mother’s milk due to the upcoming of another baby. These children are fed a low protein cereal diet that provides adequate energy but not enough protein. Their protein content in the blood is insufficient and inefficient in keeping fluids from leaking into the tissues, and as a result, their stomachs begin to appear swollen.

Kwashiorkor affects an individual by the following:

  • Some weight loss and muscle wasting, with some retention of body fat
  • Fatty degeneration of the liver
  • Development of sores and other skin problems; skin pigmentation changes
  • Dry, brittle hair that changes color, straightens and falls out easily.

It is possible to reverse the effects of Kwashiorkor with enough protein and energy given throughout time. Once treated, those may develop the disease again due to their living conditions. Although, individuals may die due to their weakened immune systems from the disease and contract other infectious diseases.

Protein-energy malnutrition is common in all countries that affect both children and adults that live in impoverished conditions and don’t have an adequate protein intake. Those at risk include children in developing countries, the elderly, the homeless, people with eating disorders and drug and alcohol addictions, and individuals with terminal diseases.


Community Resources

Link to a site regarding vegan protein – https://www.eatthis.com/best-vegan-protein-sources/ – Vegans/Vegetarians may have a harder time getting protein into their diet when they cut out meat, but there are plenty of sources that are vegan friendly.

Here’s a link to a beginner’s guide for vegetarianism: https://www.healthline.com/nutrition/vegetarian-diet-plan 

Writers, Staff. “Nutrition Resources – Publichealth.Org.” Publichealth.Org, 2020, https://www.publichealth.org/resources/nutrition/


Amoeba sisters. Jan 18, 2018, Protein Synthesis (updated). Youtube. https://www.youtube.com/watch?v=oefAI2x2CQM.

Bailey, Regina. (2020, August 28). Learn About the 4 Types of Protein Structure. Retrieved from https://www.thoughtco.com/protein-structure-373563

Kiah Connolly, M. (2020, October 02). How Much Protein is Too Much? 4 Risks of Excess Protein. Retrieved November 25, 2020, from https://www.trifectanutrition.com/blog/how-much-protein-is-too-much

Link, R. (2018, October 17). The Vegetarian Diet: A Beginner’s Guide and Meal Plan. Retrieved November 25, 2020, from https://www.healthline.com/nutrition/vegetarian-diet-plan

Miller, K. (2019, November 13). Apparently, There Are 7 Different Types Of Vegetarian Diets. Retrieved November 25, 2020, from https://www.womenshealthmag.com/food/a29700788/types-of-vegetarians/

Ouellette,R.J.,&Rawn,J.(2015).QuaternaryStructure.RetrievedNovember25,2020,from https://www.sciencedirect.com/topics/chemistry/quaternary-structure

Tertiary Structure. (n.d.). Retrieved November 25, 2020, from https://cbm.msoe.edu/teachingResources/proteinStructure/tertiary.html


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Good Health and Well-Being Copyright © 2020 by Leon Martinez Gist; San Juana Cruz; and Ana PIna Vega is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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