Proteins are basic biomolecules that serve every cell within the body. Cellular metabolism requires various types of proteins as machinery for carrying out activities and for maintaining life.

 

Structure & Composition of Proteins

The interaction of amino acids in a polypeptide chain is governed by the formation of covalent bonds known as peptide bonds. A protein is made up of 20 standard amino acids, each possessing a distinct side branch that determines a protein’s functions and characteristics. With respect to a polypeptide backbone, the spatial arrangement and order of protein subunits specify its tertiary structure [1].

 Proteins Functions

• Pepsin and many other proteins take up the form of enzymes and conduct catalytic activities within the metabolism of living organisms. An example is an enzyme for digestion that breaks down the food by acting upon it while it is in the stomach, termed pepsin [6]

• Connective tissues of human beings, alongside tissues such as skin, hair and nails, contain a protein referred to as collagen which serves to give strength, while keratin serves structural integrity [6].

• Specialized proteins such as hemoglobin serve the purpose of moving oxygen to all sections of the body from lungs, as heme and oxygen transporters transport it across. Another specialized protein known as ferritin serves the purpose of containing iron in liver [6].

• Anti-foreign agents termed as antibodies stem from proteins and serve the function of identifying strangers start neutralization setters for foreign agents [6].

• Some physiological activities are controlled by signaling hormones of insulin as an example, that take the form of proteins [6].

Protein Digestion and Absorption

The digestion of protein starts in the stomach, and progresses in the small intestines with the help of pepsin, trypsin, and chymotrypsin, all of which cut down the peptid chains into amino acids. These amino acids then get absorbed in the bloodstream, becoming available for the body to utilize [6].

Animal and Plant Sources of Protein

Proteins are sourced from both animals and plants:

– Animal-Based Proteins: These include meat, poultry, fish, eggs, and even yogurt, dairy, etc. These are the so called complete proteins [2]

– Plant-Based Proteins: You can find these in legumes, seeds, nuts and whole grains ([2]).

Protein Intake Recommendations

The Recommended Dietary Allowance or RDA of dietary protein is 0.8 grams of protein per kilogram of body weight for sedentary adults throughout the day [2]

Food Rich in Protein

• Chicken Breast: delivers 26g in 3 ounces serving [4].

• Cottage Cheese: 23.5g of protein in each cup [4]

• Lentils: serving of 1 cup of cooked lentils gives 18g protein [5].

• Peanuts: 7.3g of protein in each ounce [5]

• Eggs: containing 6g each of protein, each large egg adds up to this count [5]

Protein Quality and Bioavailability

The value of protein is determined by the quantity of amino acids present and the digestibility of the protein. Comparatively, animal proteins having higher bioavailability is a generally accepted fact when compared to plant proteins [2]

Considerations Pertaining to Health and Protein Consumption

Sufficient protein consumption is linked to:

– The preservation of muscles

– Management of weight

– Health of the bones

– Due to a lack of authority on the issue, research also suggests social engagement affords individuals with a reliable aid system a great deal of confidence.

Protein related diseases

Protein Deficiency can lead to disease ?

Yes, both consuming too little or too much protein can have negative effects on the body and may lead to various health issues. One prominent disease associated with protein deficiency is kwashiorkor. It can cause edema (swelling) in the legs. People who consume very low amounts of protein in their diet are at risk of developing this condition. Kwashiorkor can affect both children and adults, and cases are mostly reported in poor and developing countries where maintaining a balanced diet is challenging [8].

Coping with the Challenge of Protein Deficiency

The main cure for this type of disease is maintaining a good and balanced diet that includes all the essential amino acids required for the proper functioning of the body. Consuming more protein than necessary can also negatively impact health, especially in individuals who heavily rely on protein sources while cutting down on carbohydrates. Carbohydrates are also essential for the body’s proper functioning and should not be eliminated from the diet [8].

References

[1] MedlinePlus Genetics. What Are Proteins and What Do They Do? MedlinePlus, U.S. National Library of Medicine, https://medlineplus.gov/genetics/understanding/howgeneswork/protein/.

[2] MedlinePlus. “Dietary Proteins. MedlinePlus, U.S. National Library of Medicine, https://medlineplus.gov/dietaryproteins.html.

[3] 9 Important Functions of Protein in Your Body. Healthline, https://www.healthline.com/nutrition/functions-of-protein.

[4] 17 High-Protein Foods That Beat a Protein Shake.” Health, https://www.health.com/high-protein-foods-that-beat-protein-shakes-11706410.

[5] “16 Foods for High Protein Meals.” Healthline, https://www.healthline.com/nutrition/high-protein-foods.

[6] Protein. Wikipedia, Wikimedia Foundation, https://en.wikipedia.org/wiki/Protein.

[7] Protein Foods Group – One of the Five Food Groups.” MyPlate.gov, https://www.myplate.gov/eat-healthy/protein-foods.

[8] https://pressbooks-dev.oer.hawaii.edu/humannutrition/chapter/diseases-involving-proteins/