Protein is an essential nutrient in your everyday diet. Your body requires protein not only to stay healthy but also to carry out critical functions. However, a fundamental question remains—how much protein do you really need?
Interestingly, PROtein consumption in Diet of adult Indians, a General consumer surveY (PRODIGY) was conducted in seven major cities with 1260 respondents across India. As opposed to popular belief, nine out of 10 consumers had a protein-deficient diet1.
Not all sources of protein are created equal and even the protein requirement changes throughout our lives.
Discover more about proteins and the optimal levels you need depending on your goals, activity levels, etc.
What Is Protein and Why Does Your Body Need It?
Protein is a macronutrient, which means your body needs it in large amounts for functioning at optimal levels. It is made up of different types of amino acids which are attached to each other in the form of a long chain.
There are nine essential and 11 non-essential amino acids. These nine essential amino acids are not synthesized by the body and must be obtained from the diet.
Histidine, Isoleucine, Leucine, Valine, Lysine, Methionine, Phenylalanine, Threonine, and Tryptophan
Alanine, Arginine, Asparagine, Aspartic acid, Cysteine, Glutamic acid, Glutamine, Glycine, Proline, Serine, and Tyrosine
Of these essential amino acids, leucine, isoleucine, and valine are known as branched-chain amino acids (BCAAs) and have been widely used in sports and performance nutrition.
It is the sequences of these 20 amino acids that determine the structure and function of the proteins in our body.
Functions of Proteins
Protein is present throughout the body, be it muscle, blood, skin, hair, tissue, bone and, in fact, every cell of our body. Here is how protein supports your body in different ways2,3,4,5,6.
- Structure: Structural proteins, as the name suggests play a role in providing the structure and shape, and support the overall movement in the body. Collagen and keratin are examples of structural proteins—collagen is the structural element in your bones, skin, tendons, and ligaments whereas keratin is present in skin, nails, and hair.
Because of this critical function, collagen peptides are now one of the top-selling supplements in the skincare segment because of their touted benefits on skin elasticity, signs of skin ageing including fine lines and wrinkles, hydration as well as collagen production.
- Growth, repair and maintenance: Proteins are also involved in the growth and repair of muscles and tissues following daily wear and tear and post-exercise. It, thus, comes as no surprise that protein supplementation is popular among athletes and recreationally active individuals as it has been shown to improve muscle growth, fat loss, post-exercise recovery, and performance7,8,9.
- Biochemical reactions (enzymes): Enzymes along with other molecules support various chemical reactions in the body such as muscle contractions, digestion (metabolism), energy production, blood clotting, etc.
- Protection (antibodies): Proteins help in the formation of antibodies to fight infections and develop immunity. They bind to and destroy foreign particles including bacteria and viruses.
- Messengers (hormones): Messenger proteins such as hormones help transmit signals to support and coordinate biological processes between cells, tissues, and organs. Some examples include insulin and growth hormone.
- Transport and storage: Transport proteins help carry nutrients (vitamins, minerals, fatty acids, etc.), oxygen, and other molecules through the bloodstream in and out of cells. Some proteins play a role in storage. For instance, ferritin stores iron.
- Energy source: Protein can act as a source of energy in special circumstances such as fasting, low calories consumption, or extensive exercising.
- Fluid and pH balance: Proteins such as albumin and globulin play a role in maintaining fluid balance in the body by regulating the movement of water. Other proteins help in balancing the levels of acids and bases in your blood and other body fluids.
How Does Your Body Get the Protein It Needs
You can get protein from a variety of plant and animal-based food sources as well as dietary supplements.
Protein digestion, in fact, starts as soon as you start chewing your food. After the initial mechanical breakdown, enzymes or gastric juices in your stomach break the protein into small chains of amino acids. These smaller chains move into the small intestine to be further broken down into individual amino acids10.
These amino acids are then absorbed in your small intestine and released in the bloodstream to be taken to different cells of the body to do their critical jobs such as muscle building or tissue repair10.
Essential Amino Acid-Rich Proteins and Associated Health Benefits
Of the nine essential amino acids, a few have been extensively studied and commercially used in protein supplementation because of the health benefits they offer. Here are some interesting examples you should know about.
May help improve mood
Tryptophan is an essential amino acid and is involved in the production of the neurotransmitter, serotonin which has a key role in moods and sleep. Tryptophan-rich protein hydrolysates have been shown to improve reaction time, emotional functioning, and mental energy levels11. Another study showed that tryptophan supplementation decreased anxiety and increased positive mood in healthy people12.
May help support performance and recovery
BCAAs including leucine, valine, and isoleucine have been shown to improve muscle soreness and muscle recovery in resistance-trained athletes13. Another study showed that BCAAs were better than rest or passive recovery in reducing muscle soreness and improving recovery after exhaustive and damaging exercises14.
In fact, leucine supplementation in the elderly population can improve age-related muscle decline and increase muscle protein synthesis15.
How Much Protein Do I Need?
The amount of protein you need depends on various factors such as
- Body weight
- Activity levels
- Pregnancy/lactation status
Ideally, for men and women, who have a sedentary or moderately active lifestyle, the recommended protein intake is 0.83 to 1.0 gram per kg of body weight per day16.
However, in special circumstances, the protein requirement increases.
The International Society of Sports Nutrition (ISSN) recommends an overall daily protein intake in the range of 1.4 to 2.0 grams per kg body weight per day for most exercising individuals for muscle mass building and maintenance17.
The National Institute of Nutrition recommends additional protein intake in pregnant and lactating women. For instance, for women in the second trimester, an extra 9.5 g/day is needed16.
In fact, people recovering from injuries also have increased protein requirements18,19.
What Is the Best Way to Get Protein?
You can get protein from a variety of sources. Fortunately, you can hit the right protein mark, if you include healthy protein sources either through whole foods or protein supplements in your diet.
- Egg/ poultry
- Lean meats
- Dairy products
- Seeds (Hemp, sunflower, etc.)
- Legumes/lentils (beans)
However, it is not just about the quantity but the quality of protein. With that being said, high-quality protein supplements can help meet your protein needs in addition to whole food sources.
What About Protein Powders?
When comparing animal-based versus plant-based protein sources, the primary difference is in the amino acid content. Usually, animal protein contains all nine essential amino acids in adequate amounts needed by the body, whereas, plant protein may lack a few amino acids. With that being said, soy and pea protein are considered the best sources of vegan protein and have very high to almost ideal PDCAA scores.
PDCAA score or protein digestibility–corrected amino acid score is used globally as a reliable way to measure the quality of protein. For instance, whey protein and soy protein have an ideal PDCAA score of 1.0 and pea protein has an almost ideal PDCAA score of 0.93.
So, when it comes to choosing an easy-to-digest protein, the best vegan protein, or the best protein for muscle building, take the following factors into account.
- Protein content
- Amino acid profile or the PDCAA score
- Digestibility/ food sensitivities (lactose-free)
- Associated health benefits
Additionally, make sure to check the nutrition and ingredient labels to know about added sugars or unexpected components in the protein powder.
Protein is critical in your everyday diet. With its role in muscle and tissue repair, fluid balance, structural support, and others, it is high time you reconsider protein quantity and quality. Not getting enough protein can have a negative impact on your health. However, there are different opinions on how much protein you really need. The answer really depends on your age, body weight, activity levels, health status, and fitness goals.
- Mahajan M. Protein Consumption in Diet of Adult Indians: A General Consumer Survey (PRODIGY).
- What are proteins and what do they do? [Internet]. MedlinePlus. U.S. National Library of Medicine; 2021 [cited 2023Feb10]. Available from: https://medlineplus.gov/genetics/understanding/howgeneswork/protein/
- LaPelusa A, Kaushik R. Physiology, Proteins. InStatPearls [Internet] 2021 Nov 21. StatPearls Publishing.
- Yeo J, Jung G, Tarakanova A, Martín-Martínez FJ, Qin Z, Cheng Y, Zhang YW, Buehler MJ. Multiscale modeling of keratin, collagen, elastin and related human diseases: Perspectives from atomistic to coarse-grained molecular dynamics simulations. Extreme Mechanics Letters. 2018 Apr 1;20:112-24.
- Busher JT. Serum albumin and globulin. Clinical methods: The history, physical, and laboratory examinations. 1990;3:497-9.
- Carlson GP. Fluid, electrolyte, and acid-base balance. InClinical biochemistry of domestic animals 1997 Jan 1 (pp. 485-516). Academic Press.
- Kimball SR, Jefferson LS. Signaling pathways and molecular mechanisms through which branched-chain amino acids mediate translational control of protein synthesis. The Journal of nutrition. 2006 Jan 1;136(1):227S-31S.
- Wirunsawanya K, Upala S, Jaruvongvanich V, Sanguankeo A. Whey protein supplementation improves body composition and cardiovascular risk factors in overweight and obese patients: a systematic review and meta-analysis. Journal of the American College of Nutrition. 2018 Jan 2;37(1):60-70.
- Kim J, Lee C, Lee J. Effect of timing of whey protein supplement on muscle damage markers after eccentric exercise. Journal of exercise rehabilitation. 2017 Aug;13(4):436.
- Silk DB, Grimble GK, Rees RG. Protein digestion and amino acid and peptide absorption. Proceedings of the Nutrition Society. 1985 Feb;44(1):63-72.
- Mohajeri MH, Wittwer J, Vargas K, Hogan E, Holmes A, Rogers PJ, Goralczyk R, Gibson EL. Chronic treatment with a tryptophan-rich protein hydrolysate improves emotional processing, mental energy levels and reaction time in middle-aged women. British Journal of Nutrition. 2015 Jan;113(2):350-65.
- Kikuchi AM, Tanabe A, Iwahori Y. A systematic review of the effect of L-tryptophan supplementation on mood and emotional functioning. Journal of dietary supplements. 2021 May 4;18(3):316-33.
- Waldron M, Whelan K, Jeffries O, Burt D, Howe L, Patterson SD. The effects of acute branched-chain amino acid supplementation on recovery from a single bout of hypertrophy exercise in resistance-trained athletes. Applied Physiology, Nutrition, and Metabolism. 2017;42(6):630-6.
- Rahimi MH, Shab-Bidar S, Mollahosseini M, Djafarian K. Branched-chain amino acid supplementation and exercise-induced muscle damage in exercise recovery: A meta-analysis of randomized clinical trials. Nutrition. 2017 Oct 1;42:30-6.
- Xu ZR, Tan ZJ, Zhang Q, Gui QF, Yang YM. The effectiveness of leucine on muscle protein synthesis, lean body mass and leg lean mass accretion in older people: a systematic review and meta-analysis. British Journal of Nutrition. 2015 Jan;113(1):25-34.
- Nutrient Requirement for Indians. Indian Council of medical research and National institute of Nutrition; 2020 [cited 2023Feb10]. Available from: https://www.nin.res.in/RDA_short_Report_2020.html
- Jäger R, Kerksick CM, Campbell BI, Cribb PJ, Wells SD, Skwiat TM, Purpura M, Ziegenfuss TN, Ferrando AA, Arent SM, Smith-Ryan AE. International society of sports nutrition position stand: protein and exercise. Journal of the International Society of Sports Nutrition. 2017 Jun 20;14(1):20.
- Frankenfield D. Energy expenditure and protein requirements after traumatic injury. Nutrition in clinical practice. 2006 Oct;21(5):430-7.
Long CL, Schaffel N, Geiger JW, Schiller WR, Blakemore WS. Metabolic response to injury and illness: estimation of energy and protein needs from indirect calorimetry and nitrogen balance. Journal of Parenteral and Enteral Nutrition. 1979 Nov;3(6):452-6.
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