This is what proteins do: 5 functions and examples

Protein is an essential macronutrient that forms the building blocks of every cell in your body. When you consume animal or plant proteins, your body breaks them down into amino acids. Your cells use amino acids to build and repair body tissues such as muscles, skin, organs and bones. Protein also provides fuel for energy, supports immune function and regulates vital body processes such as metabolism, growth and digestion.

This article discusses the numerous functions of protein in the human body, its effect on body weight, protein-rich foods, and ideal intake levels. It also covers what happens to your body when you consume too much protein.

Protein functions in the human body

Proteins are the workhorse of the body’s cells and are crucial for maintaining a healthy and well-functioning body. Protein consists of amino acid chains and plays a role in virtually every body process, from building and repairing tissues to boosting metabolism and regulating the body’s numerous biochemical reactions.

Build and repair tissue

One of the most important jobs of proteins is to form and maintain the structural foundation of your body: muscles, bones, skin, hair and nails, and internal organs. Every cell in your body contains proteins; these are essential to the structure and function of every part of the human body. The amino acids that make proteins are the raw materials for building and repairing body tissues.

Your body is constantly breaking down proteins; this constant renewal (replacing old proteins with new) is essential for repairing and regenerating body tissues. There are times when your protein needs increase, such as when you are recovering from an illness, surgery or injury. Older adults and pregnant or breastfeeding people need more protein to maintain optimal health.

Regulate metabolic processes

Protein is the basis for creating enzymes, which are important for every biochemical reaction and function in your body.

Enzymes are complex proteins that act as catalysts for chemical reactions in the body related to energy production, growth, nutrient digestion, muscle function and blood clotting. They also play a role in the body’s detoxification process, lowering the risk of certain diseases and conditions (for example, heart disease and Alzheimer’s).

Act as chemical messengers

Hormones act as chemical messengers that travel in the bloodstream and regulate many body processes. Many hormones, called peptide hormones, are made up of proteins. Peptide hormones are critical in regulating growth, mood and metabolism. Examples of protein-based hormones include:

• Insulin: Promotes the absorption of glucose into the cells as an energy source.
• Epinephrine (adrenaline): Helps maintain cardiovascular health and activates the body’s fight-flight responses.
• Oxytocin: Oxytocin is known as the ‘love hormone’ and plays a role in human behaviors such as trust, romantic and familial bonds, and sexual arousal.
• Thyroxine: A thyroid hormone that regulates the heart, metabolism, digestion, brain development and more.
• Human growth hormone: Promotes growth in children and maintains body structure and metabolism in adults.

Support the immune system

Many components of the immune system are protein-based, making proteins essential for optimal immune function and protecting your health. For example, cytokines are small proteins that control the growth and activity of other immune cells. When cytokines enter the bloodstream, they signal and regulate the action and function of other immune cells to protect the body from potential threats. Cytokines also play a role in the body’s inflammatory response.

Antibodies are proteins that circulate through the bloodstream and identify and neutralize foreign substances, such as bacteria and viruses, that could threaten your health.

Maintain fluid balance

Proteins help maintain and regulate the body’s fluid balance. Albumin is a protein that attracts and retains water in the bloodstream. This creates a pressure called oncotic pressure, which counteracts the outward pressure of fluids pressing against blood vessel walls, preventing fluid from leaking into surrounding tissues.

Albumin also helps regulate the movement of lymphatic fluid, helps prevent tissue edema (swelling) and ensures proper fluid distribution throughout the body.

Protein sources and how to eat more

Getting enough protein in your diet is an excellent way to support your overall health. There are many food sources of protein, including animal and plant protein foods. Whatever your preference, eating a variety of protein-rich foods is the best way to ensure your body gets the nutrients it needs.

Animal proteins

Animal proteins, such as those found in meat, poultry, fish, eggs and dairy products, are considered complete proteins. Animal protein foods contain all nine essential amino acids, which your body cannot produce on its own, and you must consume the food you eat.

Animal protein-rich foods include:

• Meat: Beef, pork, goat, ham, lamb or game (e.g. deer, bison)
• Poultry: Chicken, turkey, Cornish hen, duck, pheasant
• Seafood: Fish (e.g. tilapia, flounder, haddock, tuna, salmon) and crustaceans (e.g. scallops, lobster, oysters, shrimp)
• Dairy: Cow’s milk, cheese, yogurt
• Eggs

Vegetable proteins

Plant proteins are incomplete proteins, meaning they are missing one or more essential amino acids. By including different plant-based protein sources in your meals, you can consume complementary proteins to ensure you get all the essential amino acids.

Plant-based protein foods include:

• Nuts and seeds: Almonds, walnuts, cashews and pistachios; chia, pumpkin, sesame and sunflower seeds
• Soy products: Tofu, tempeh
• Beans, peas and lentils: Black, garbanzo, kidney, lima, pigeon, split, black-eyed peas and lentils

Boosting your protein intake

Getting enough protein is essential for maintaining good health. Here are some tips to increase your protein intake:

• Start your day with protein: Eat a protein-rich breakfast with eggs, yogurt or a protein smoothie.
• Smart snacking: Choose snacks that are a good source of protein, such as a handful of nuts, seeds or edamame.
• Add protein to every meal: Include protein sources, including salads, stir-fries and soups.
• Turn: Mix up your protein sources throughout the week to ensure you get the essential amino acids and satisfy your taste buds.

Protein role in weight loss or weight gain

Although proteins do not directly lead to weight loss or weight gain, they do influence your appetite, metabolism and body composition (e.g. muscle mass) – all factors that play a role in weight management.

Satiety and appetite control

Compared to carbohydrates and fats, protein is more satiating, meaning it can help you feel full longer, which can help control appetite and promote weight loss. Research shows that people on a high-protein diet tend to consume fewer calories.

Metabolism boost

Digesting and metabolizing proteins requires more energy than carbohydrates or fats, leading to a slight increase in calorie burn known as the thermic effect of food. This can contribute to a small but measurable calorie deficit over time.

Muscle building

Muscle tissue burns more calories than fat at rest. Higher protein intake helps maintain muscle mass during weight loss, which can boost metabolism and maintain calorie burning. However, excessive protein intake above recommended levels will not accelerate weight loss but may contribute to weight gain.

What does too much protein do?

Although protein is a fundamental nutrient for health, exceeding the recommended intake can harm your health. Moderation is key, and following recommended protein intake guidelines is the best approach to protein consumption.

Effects of a heavy meat diet

Diets high in certain types of proteins, including red and processed meat, may put you at risk for certain diseases, including heart disease, chronic kidney disease and cancer.

• Heart disease: Research findings show a strong link between diets high in red meat and processed meat consumption and the risk of cardiovascular disease, stroke and heart failure.
• Cancer: Some research suggests that a diet high in red and processed meat increases the risk of colorectal, prostate and pancreatic cancer.
• Kidney disease: Excessive protein intake can negatively affect kidney function because the kidneys have to work harder to filter and remove waste products. A diet high in meat can be dangerous for people with kidney disease.

Protein shakes

Protein shakes can be a convenient way to add protein to your diet, but relying on them as your sole source of protein can be more harmful than helpful. Protein shakes are powders made with animal or plant sources (e.g. casein, whey, soy, hemp).

While fitness enthusiasts may tout them as a miracle solution to fuel your body before or after training, consuming protein shakes and powders comes with health risks.

A 2018 study found high levels of heavy metals such as arsenic, lead and mercury in several popular protein shakes. These contaminants, likely from contaminated soil or water used in ingredient production, can lead to organ damage, immune system dysfunction and damage to your nervous system.

And while many protein shakes can help increase your protein intake, they also add sugars, such as high fructose corn syrup or artificial sweeteners, which can contribute to weight gain, disrupt a healthy gut microbiome and increase the risk of type 2 diabetes and heart disease. .

Resume

In addition to providing nourishment, proteins are an essential macronutrient that your body needs for optimal function and maintenance. Protein builds and repairs body tissues such as muscles, skin and bones, provides energy, supports immune function and regulates important body processes. While protein is important, too much can lead to adverse health effects, especially large amounts of red and processed meat. Consuming protein from animal and plant sources is the best way to ensure your body gets the protein and other nutrients it needs to support your health and well-being.