Protein is an essential macronutrient. It's made up of amino acids, which are the building blocks for healthy muscles, skin, bones, and even hormones. They are essential for repair and growth, creating enzymes and antibodies for robust immunity, and synthesizing neurotransmitters that balance our moods and cognitive functions.
Protein is not just important; it's essential! It's one of the most crucial nutrients needed by the human body for optimal health and well-being. Proteins are the building blocks of life, and they play a vital role in maintaining healthy muscles, bones, skin, and even hormonal health.
Protein is also essential for repairing damaged tissues, producing enzymes and hormones, and building strong immune systems. 
Protein is made up of amino acids, also known as the building blocks of protein. 20 different amino acids are used to make proteins in the body; nine of these are considered essential, meaning they must be obtained through the diet and cannot be made within the body.
In this article, we will examine the importance of daily protein intake and amino acids for each bodily system using the functional medicine model. We will also explore the importance of protein intake for muscle health, aging, and overall well-being and dive into how much protein is enough to see great results.
The Digestive System
The digestive system is responsible for breaking down food into its component parts, including proteins. Protein digestion begins in the stomach, where hydrochloric acid and enzymes called proteases break down the protein into smaller peptides and amino acids. These smaller proteins and amino acids are then absorbed into the bloodstream through the intestinal lining.
Adequate protein intake is essential for maintaining the integrity of the intestinal lining and preventing leaky gut syndrome. Leaky gut syndrome is a condition in which the intestinal lining becomes permeable, allowing toxins and undigested food particles to enter the bloodstream. This can cause initiate and immune response, triggering inflammation and contributing to the development of autoimmune diseases. One particular amino acid, known as L-Glutamine, is essential for maintaining a healthy gut lining.
The Immune System
The immune system is responsible for protecting the body against infection and disease. It's like an army that constantly works to protect us from external threats. It is made up of various tissues, cells, and proteins that work together to identify and eliminate pathogens and even mutated cells, as seen in cancer.
Protein is essential for the production of antibodies, which recognize and bind to specific pathogens. Antibodies are produced by B cells, which are a type of white blood cell. These cells require amino acids to synthesize antibodies, so adequate protein intake is essential for optimal immune function.
Protein and amino acids also play a crucial role in mental health. Amino acids are the building blocks of neurotransmitters, which are chemical messengers that transmit signals between neurons in the brain.
Neurotransmitters are responsible for regulating mood, emotions, and cognitive function. Some neurotransmitters, such as serotonin and dopamine, are derived from amino acids found in dietary protein.
For example, the amino acid tryptophan is used to synthesize serotonin, which is associated with mood regulation and sleep. Research has shown that low levels of dietary protein can lead to decreased neurotransmitter synthesis, which can contribute to depression, anxiety, and other mental health disorders. Therefore, adequate protein intake is important for maintaining optimal mental health and cognitive function.
The Endocrine System
The endocrine system is responsible for producing hormones that regulate various bodily functions, including metabolism, growth, and development. Hormones are proteins or peptides that are produced in glands and released into the bloodstream.
Adequate protein intake is important for the production of hormones, as many hormones are made up of amino acids. For example, insulin, which regulates blood sugar levels, is a peptide hormone made up of two amino acid chains.
Muscle mass also acts as a “sponge” for blood glucose since it stores and uses glucose for energy. Insulin signals muscle cells to absorb glucose from the bloodstream and use it for energy or store it for later use. With more muscle mass, the body has more places to store glucose, which can help to regulate blood sugar levels, supporting metabolic health and boosting weight loss (by reducing body fat).  
The Muscular System
The muscular system is responsible for movement and stability. It is made up of three types of muscle: skeletal, smooth, and cardiac. Skeletal muscle is the muscle that is attached to bones and is responsible for voluntary movement.
Protein is essential for the growth and repair of skeletal muscle tissue. During exercise, skeletal muscle tissue is damaged, and protein is required for repair and growth. Additionally, protein is necessary for the synthesis of new muscle tissue, which is important for muscle hypertrophy (i.e., muscle growth). 
Protein is also crucial for maintaining healthy skin. The skin is the body's largest organ, and it is constantly renewing itself. Amino acids are essential for the production of collagen and elastin, two proteins that provide structure and elasticity to the skin. 
Collagen makes up about 75% of the skin's dry weight and is responsible for maintaining the skin's strength and firmness. Elastin, on the other hand, allows the skin to stretch and return to its original shape. Without adequate protein intake, the skin may become dry, wrinkled, and saggy. Additionally, research has shown that collagen supplements may improve skin hydration, elasticity, and texture. Therefore, consuming adequate amounts of high-quality protein is important for maintaining healthy and youthful-looking skin.  
Overall Health and Protein Intake - How Much Protein Is Enough?
In addition to the bodily systems discussed above, protein is important for overall health and wellness. It provides a feeling of fullness and can aid in healthy weight management by reducing appetite and increasing metabolism. Adequate protein intake has also been shown to improve blood sugar control and lower blood pressure.   
While dietary reference intakes may vary, the usual Recommended Dietary Allowance (RDA) is a minimum of 0.8 grams of protein per kilogram of body weight per day for adults. However, this amount may not be sufficient for athletes or those with a very high physical activity level, older adults, pregnant women, or individuals with certain health conditions. 
A common recommendation for those wishing to gain muscle mass is 1 gram of protein per pound of your ideal body weight.
If you’re unsure, you can always search for a protein calculator online to help estimate how much protein you need as a part of your healthy lifestyle. 
It is also important to distribute protein intake evenly throughout the day rather than consuming it all at once. This allows for a constant supply of amino acids to the muscles, which can help build muscle and support a healthier body composition by promoting muscle protein synthesis.
It's worth noting that not all sources of protein are created equal. Animal protein, such as meat, poultry, fish, and dairy (especially greek yogurt), are considered high-quality proteins as they contain all the essential amino acids in the right amounts. Plant-based proteins usually consumed in vegan diets, such as beans, lentils, and nuts, are lower in certain essential amino acids and are often “incomplete proteins,” and have a lower protein quality. This means it's important to meal plan and combine various plant foods to ensure a balanced diet with adequate protein intake.
Aging and Protein Intake
As we age, our muscle mass and strength naturally decline. This type of muscle loss is known as sarcopenia and can lead to an increased risk of falls and fractures. Adequate daily protein intake is essential for maintaining muscle mass and function as we age. 
Research has shown that older adults may need to eat more protein to maintain muscle mass and function than younger adults. It has been recommended that a daily protein intake of at least 1.2 - 1.6 grams per kilogram of body weight may be required to maintain muscle mass and function in older adults.
Protein and amino acids are essential for optimal health and function of all bodily systems. Adequate protein intake is important for digestive health, immune function, hormonal balance, muscular health, and overall health and wellness. As we age, higher amounts of protein may be required to maintain muscle mass and function. It's important to consume a variety of high-quality protein sources and distribute protein intake evenly throughout the day. By focusing on protein as a vital nutrient, we can support the health and well-being of our entire body.
Note: This article is for informational purposes only and not intended for use as medical advice. Always consult your healthcare provider before starting any dietary supplement.