Protein: Benefits, function, types, sources, deficiency

Proteins are much more than just a part of your diet; they are the building blocks of life. Every cell in your body relies on these vital molecules for structure, function, and regulation.

Think of proteins as the workforce that keeps your body running smoothly, from building muscles to bolstering your immune system.

Remember, protein is not just a nutrient; it’s a key player in keeping you healthy and active. Whether you’re looking to improve your diet, understand your nutritional needs better, or simply curious about how proteins impact your health, this guide has got you covered.

What is the main benefit of protein?

When we talk about protein, it’s easy to picture gym-goers with their protein shakes and athletes bulking up on chicken breasts.

But protein’s benefits stretch far beyond just building muscle. This essential nutrient plays a crucial role in almost every bodily function, making it vital for everyone, not just fitness enthusiasts [1].

Let’s break down the numerous benefits of protein in a way that’s easy to understand and apply to your daily life.

1. Muscle growth and repair

Muscle growth and repair are crucial roles of protein, especially for those leading an active lifestyle. Here’s how it works:

  • During exercise, muscles endure small tears. Protein steps in to repair these, leading to muscle growth and increased strength.
  • Not just for athletes, protein is vital for anyone to maintain muscle health, essential for mobility and overall well-being.
  • Post-exercise, protein helps in the quick recovery of muscle tissues, reducing soreness and enhancing readiness for your next workout.
  • Regular protein intake is key in preventing muscle loss, which is especially important as we age.

Beyond size, protein is crucial for sustaining muscle strength and keeping you strong and active.

Remember, adequate protein is a non-negotiable part of a healthy, active lifestyle, regardless of your fitness level.

2. Weight managment

Weight management is a key benefit of protein, often overlooked in discussions about diet and health. 

Protein is more satisfying than carbs or fats, helping you feel full longer. This reduces the urge to snack and overeat [2]. High protein intake can slightly increase the number of calories you burn, helping in weight management.

When losing weight, a high-protein diet can help ensure more of the weight lost is fat, not muscle. Once you’ve lost weight, protein can help maintain that loss, preventing regain.

Protein-rich foods are diverse, making it easier to create satisfying, low-calorie meals that fit your lifestyle. Protein plays a critical role in helping manage and maintain a healthy weight, which is crucial for overall health and wellness.

3. Bone health

Protein plays a significant role in maintaining bone health, an aspect often overshadowed by its muscle-building reputation. Here’s how it contributes:

  • Protein is a key component of bone structure, contributing to strength and density.
  • Adequate protein intake is linked to a lower risk of bone fractures, which is particularly important as we age.
  • As you get older, protein helps in maintaining bone mass, which is crucial for preventing conditions like osteoporosis.
  • Protein works alongside calcium and other minerals to optimize bone health, demonstrating the importance of a balanced diet.
  • Essential at every life stage, protein supports bone development in youth and helps maintain bone health in adulthood.

Understanding and valuing protein’s role in bone health is key to a holistic approach to maintaining a strong and healthy body.

bone health

4. Boosting metabolism and increasing fat-burning

Boosting metabolism and increasing fat burning are lesser-known yet significant benefits of protein.

Protein causes your body to burn more calories while processing than fats or carbohydrates because of its increased thermic action.

An increase in protein intake can boost fat burning, which can help with body composition and weight loss objectives.

Maintaining muscle mass through a sufficient protein intake can increase overall metabolism since muscle burns more calories than fat.

Research has indicated that increasing one’s protein consumption can help reduce fat, specifically around the abdomen.

By enhancing metabolism and aiding in fat loss, protein can be a powerful tool in sustaining long-term weight loss. Incorporating protein into your diet can thus be a strategic move in enhancing your body’s natural fat-burning and metabolic processes.

5. Lowering blood pressure

Lowering blood pressure is another significant health benefit of protein, particularly important for heart health. Here’s how protein plays a role:

  • Studies have linked higher protein intake, especially from plant sources, to lower blood pressure levels.
  • Protein can help improve the health of your arteries, reducing the risk of heart disease [3].
  • Protein can counterbalance the effects of sodium, a known contributor to high blood pressure.
  • By maintaining the health of your blood vessels, protein aids in overall circulatory health.
  • Incorporating a variety of protein sources, including fish, lean meats, and plant-based proteins, can maximize these benefits.

Understanding the role of protein in managing blood pressure can be a key element in maintaining a heart-healthy diet.

Why is protein function important?

Protein is more than just a component of what we eat; it’s a fundamental building block of life, playing a critical role in the health and functioning of the human body.

Understanding the role and importance of protein is key to appreciating its impact on our overall health and well-being.

Cell structure and function

Protein is fundamental to cell structure and function, a cornerstone of how our bodies operate. Here’s a closer look at its role:

  • Building blocks of cells: Proteins are essential components of all cells, giving them structure and stability.
  • Enzymatic activities: Many proteins act as enzymes, speeding up vital chemical reactions within cells. This includes processes like DNA replication and energy production.
  • Cellular communication: Proteins aid in cell signaling, ensuring cells communicate effectively, a process vital for overall body function.
  • Transporting nutrients: Some proteins in cell membranes transport nutrients into and out of cells, which is crucial for nourishment and waste removal.
  • Defense mechanisms: Proteins play a role in the body’s defense, identifying and neutralizing foreign invaders like bacteria and viruses.

The intricate role of protein in cell structure and function underlines its importance in maintaining a healthy, well-functioning body.

Enzymatic functions 

Enzymatic functions are among the most vital roles proteins play in our bodies. Here’s a snapshot of this crucial aspect:

  • Catalyzing biochemical reactions: Proteins, in the form of enzymes, speed up essential biochemical reactions, making life-sustaining processes faster and more efficient.
  • Aiding digestion: Enzymatic proteins break down the food we eat into nutrients that our bodies can absorb [4].
  • Energy production: They play a key role in the metabolism of food, converting it into the energy that powers every cell in our body.
  • DNA replication: Proteins are involved in the replication of DNA, ensuring genetic information is accurately copied and passed on.
  • Signal transduction: Enzymes help in transmitting signals within cells, essential for various cellular functions, including responding to external stimuli.

Understanding proteins as enzymes highlights their indispensable role in keeping our bodies functioning at their best.

Transport and storage

The roles of protein in transport and storage within the body are both fascinating and essential. Here’s how they contribute:

  • Moving molecules: Proteins are integral in transporting molecules across cell membranes, ensuring essential nutrients and minerals reach their destinations.
  • Oxygen delivery: Hemoglobin, a protein in red blood cells, transports oxygen from the lungs to other parts of the body and carries carbon dioxide back to the lungs.
  • Storing iron: Ferritin, another protein, stores iron in the body, releasing it when needed.
  • Balancing fluids: Proteins in blood plasma help maintain proper fluid balance between blood vessels and body tissues.
  • Vitamin carriage: Certain proteins bind to vitamins and minerals, transporting them through the bloodstream to various organs.

These transport and storage functions underline the indispensable role proteins play in maintaining the body’s health and equilibrium.

Maintaining fluid and pH balance

Maintaining fluid and pH balance in the body is a critical function where proteins play a key role. Here’s how they manage these essential tasks:

  • Regulating fluid balance: Proteins in the blood, like albumin, help maintain the balance of fluid between the bloodstream and the body’s tissues. This prevents swelling or edema.
  • Maintaining pH levels: Proteins act as buffers, helping to maintain the body’s pH levels within a narrow range. This ensures all biochemical processes function optimally.
  • Electrolyte balance: Proteins assist in balancing electrolytes, which are crucial for nerve and muscle function.
  • Supporting kidney function: Proteins play a role in kidney function, filtering and removing waste products from the blood.
  • Osmotic pressure: They help maintain osmotic pressure, which ensures a stable environment for cells to function.

Understanding proteins’ role in fluid and pH balance showcases their importance in keeping our body’s internal environment stable and healthy.

Providing energy

Protein, while not the primary source of energy for the body, plays a crucial role in providing energy, especially under certain conditions. Here’s how it contributes:

  • Alternative energy source: When carbohydrates are scarce, the body breaks down proteins to produce energy.
  • Supports metabolism: Protein helps maintain lean muscle mass, which in turn supports a healthy metabolism.
  • Energy during exercise: During prolonged exercise, when the body’s carbohydrate stores are depleted, it turns to protein for additional energy.
  • Post-workout recovery: After exercise, protein helps replenish energy stores and repair muscle tissues.
  • Stabilizes blood sugar: By slowing digestion, protein helps regulate blood sugar levels, providing a stable and sustained source of energy.

Understanding protein’s role in energy provision highlights its importance in maintaining balanced energy levels and overall metabolic health.

What are the 4 main types of protein?

Understanding the different types of protein is crucial, as each type serves unique functions and benefits in our bodies. Let’s explore the diverse world of proteins and how they contribute to our health and well-being.

1. Complete vs. incomplete proteins

Understanding the difference between complete and incomplete proteins is key to a balanced diet. Here’s a quick guide:

Complete proteins

  • Include each of the nine necessary amino acids that the body is unable to manufacture.
  • Mostly present in animal-based foods like dairy, fish, meat, and poultry.
  • For plant-based diets, soy and quinoa are excellent complete protein sources.

Incomplete proteins

  • Deficient in one or more of the necessary amino acids.
  • Frequently present in meals made from plants, like legumes, nuts, and seeds.
  • Combining different plant-based proteins, like rice with beans, can form a complete protein.

Knowing this helps in planning meals, especially for vegetarians and vegans, to ensure all essential amino acids are included in the diet.

It’s not just about the quantity of protein but also the quality and diversity of your protein sources that contribute to overall health and nutrition.

2. Animal-based proteins

Animal-based proteins are a major part of many diets, known for being complete sources of protein [5]. Here’s a look at various types:

  • Meat: Beef, pork, and lamb are rich in protein and essential nutrients. Opting for lean cuts can help manage fat intake.
  • Poultry: Chicken and turkey provide high-quality protein with less fat than red meats. They’re versatile in recipes and are widely consumed.
  • Fish: Not only a great protein source but also rich in omega-3 fatty acids, fish like salmon and tuna are excellent for heart health.
  • Eggs: Often referred to as a ‘perfect protein’, eggs contain all essential amino acids and are incredibly versatile in cooking.
  • Dairy products: Milk, cheese, and yogurt offer protein and calcium for bone health. They can be part of various meals and snacks.

Incorporating these foods into your diet can provide the necessary protein your body needs.

However, it’s important to balance animal-based proteins with plant-based ones for overall dietary health.

animal-based proteins

3. Specialized protein sources

Specialized protein sources have become increasingly popular, catering to diverse dietary needs and preferences. Here’s a glance at some unique options:

  • Protein powders: Whey and casein are popular among athletes for muscle recovery. Plant-based powders like pea, rice, or hemp are great for vegans or those with dairy allergies.
  • Insect protein: Sustainable and nutrient-rich, insects like crickets and mealworms are consumed worldwide. They’re ground into powders for an unnoticeable inclusion in foods.
  • Lab-grown meats: A revolutionary approach to protein, these meats are developed from animal cells. They aim to offer a sustainable, ethical alternative to animal farming.
  • Seaweed and algae: Rich in protein, these are sustainable options gaining popularity. Spirulina and chlorella are common supplements.
  • Nutritional yeast: A staple in vegan diets, it’s a complete protein and is often used for its cheesy, nutty flavor in various dishes.

Exploring these specialized sources can diversify your protein intake and introduce new flavors and textures to your diet.

4. Protein blends

Protein blends are a smart way to get the full spectrum of amino acids and maximize the benefits of protein.

These blends can be particularly useful for those who have varied dietary preferences or restrictions. Here’s how they work:

  • Combining plant-based sources: For vegetarians and vegans, blending different plant proteins, like rice and beans or lentils and nuts, ensures a complete amino acid profile.
  • Mixed protein supplements: Many protein powders now combine different sources, like whey with plant-based proteins, to offer a broader range of amino acids.
  • Meal variety: Incorporating a mix of protein sources in your daily meals – like fish with legumes or dairy with seeds – can also ensure a well-rounded protein intake.
  • Enhanced nutrient profile: Blending proteins not only complements amino acid profiles but also combines the unique nutrients each source offers, like iron from legumes and omega-3s from fish [6].

Using protein blends is a practical and effective approach to meet your dietary needs while keeping meals interesting and nutritionally balanced.

What foods are highest in protein?

Protein sources are diverse, catering to various dietary needs and preferences. Here’s a rundown of some key sources:

Animal sources

Animal sources of protein are widely recognized for their complete amino acid profiles, making them a key part of many diets. Here’s a brief overview:

  • Beef, pork, and lamb are high in protein but opt for lean cuts to manage fat intake.
  • Chicken and turkey, known for their lean protein, are great for muscle building and repair.
  • Offers not just protein but also essential omega-3 fatty acids. Salmon and tuna are popular choices.
  • A versatile and complete protein source, eggs can be incorporated into numerous meals.
  • Milk, cheese, and yogurt provide not only protein but also calcium for bone health.

Plant sources

Plant sources of protein are essential, especially for vegetarians and vegans, and they offer a variety of health benefits. Here’s a quick look at some key options:

  • Beans, lentils, and chickpeas are not only rich in protein but also fiber, vitamins, and minerals [7].
  • Almonds, walnuts, flaxseeds, and chia seeds provide a good protein punch along with healthy fats.
  • Grains like quinoa and brown rice offer protein and are great for energy.
  • Tofu, tempeh, and edamame are versatile protein sources, fitting well into many different recipes.
  • Often overlooked, peas are a good source of protein, adding a nutrient boost to meals.


Protein supplements are a convenient way to boost your intake, especially for those with increased needs or busy lifestyles. Here’s what you should know:

  • Whey protein: Popular among athletes, whey protein is fast-absorbing, making it ideal for post-workout recovery.
  • Casein protein: Slow-digesting, casein is great for providing a steady supply of amino acids, often taken before bed.
  • Plant-based proteins: Pea, rice, and hemp proteins are excellent for vegans or those with dairy allergies.
  • Blended formulas: Combining different protein sources, these offer a balanced profile of amino acids.
  • Protein bars and ready-to-drink shakes: Handy for on-the-go nutrition, these can be quick meal replacements or snacks.

What happens if the body is deficient in protein?

Protein deficiency, though often overlooked, is a significant health concern that can lead to various complications.

It’s crucial to recognize the signs and understand the importance of adequate protein intake for overall health.

Signs and symptoms

Recognizing the signs and symptoms of protein deficiency is vital for timely intervention and maintaining good health. Here are some key indicators:

  • Muscle weakness and wasting: One of the earliest signs is a loss of muscle mass, leading to weakness and fatigue [8].
  • Edema: Swelling, particularly in the legs and feet, due to fluid accumulation is a common symptom.
  • Brittle hair and nails: Protein deficiency often results in hair thinning, hair loss, and brittle nails.
  • Skin problems: Dry, flaky skin or rashes can be a sign of inadequate protein intake.
  • Hunger and cravings: Constant hunger and cravings for protein-rich foods might indicate deficiency.
  • Slow healing: Wounds heal slowly and frequent infections suggest a weakened immune system due to low protein levels.
  • Mood changes: Irritability, mood swings, and depression can also be linked to inadequate protein intake.

Being aware of these signs can prompt a dietary review and, if necessary, a consultation with a healthcare professional to address potential protein deficiency.

Causes of protein deficiency

Protein deficiency can occur due to several factors. Understanding these causes can help prevent and address the issue effectively. Here are the main causes:

  • Inadequate dietary intake: Not consuming enough protein-rich foods is the most common cause. This can happen due to a lack of awareness or limited access to protein sources.
  • Increased protein needs: Certain life stages or conditions, like pregnancy, breastfeeding, intense athletic training, or recovery from illness, require more protein.
  • Chronic illnesses: Diseases like cancer, kidney disease, or conditions that impair nutrient absorption can lead to protein deficiency.
  • Eating disorders: Conditions like anorexia nervosa or bulimia can result in severely reduced protein intake.
  • Aging: Older adults often experience reduced appetite and dietary restrictions, leading to inadequate protein consumption.
  • Economic factors: In some regions, economic constraints limit access to adequate and varied protein sources.

Addressing these factors is key to managing and preventing protein deficiency. Regular dietary assessments and seeking professional advice, when needed, can help maintain optimal protein levels for good health.


Protein is much more than a nutrient; it’s a fundamental pillar of health, playing a crucial role in everything from muscle growth to immune system support.

Understanding its importance, along with the signs of deficiency and the diverse sources available, empowers you to make informed choices for your health and well-being.

Protein is a versatile and essential nutrient that deserves a prominent place in your diet. Whether you’re an athlete, a busy professional, a growing teenager, or in your golden years, the right amount of high-quality protein is key to maintaining a healthy, active life.


What is the function of protein?

Protein plays a crucial role in building and repairing tissues, making enzymes and hormones, and supporting immune function, among other vital bodily processes.

What is the source of protein?

Protein sources include animal products like meat, dairy, and eggs, as well as plant-based foods such as legumes, nuts, seeds, and whole grains.

What is the deficiency of protein?

Protein deficiency is a condition where the body does not get enough protein to meet its needs, leading to symptoms like muscle weakness, hair loss, and weakened immune function.


The information included in this article is for informational purposes only. The purpose of this webpage is to promote broad consumer understanding and knowledge of various health topics. It is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new health care regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this website.