Protein Summary
Protein: The Workhorses of Life
Protein is derived from a Greek word meaning of primary importance.
Proteins are essential to every living organism.
Next to water, protein makes up the largest proportion of the body.
Proteins are present in every cell, from hair and facial muscles to toenails.
Proteins provide structure to bones, muscles, and skin.
Enzymes and hormones, which are proteins, conduct chemical reactions in the body.
Protein as an Energy Nutrient (Macronutrient)
Protein is an energy nutrient, making it a macronutrient.
Protein is used to build muscle mass; increasing muscle mass actually means converting protein into muscle tissue.
Protein aids muscle recovery after injury or exercise by providing specific proteins to repair damaged muscle tissue.
Muscle, derived from protein, enables body movement through shortening and lengthening contractions.
Structural Support: Collagen
Protein contributes to body structure through collagen.
Collagen forms ligaments and tendons.
Tendons connect muscle to bone, while ligaments connect bone to bone.
Collagen fibers facilitate body movement by allowing muscles to pull on bones.
Enzymes: Catalyzing Chemical Reactions
Enzymes, derived from protein, facilitate chemical reactions by binding to substrates.
Enzyme-substrate binding creates products that drive chemical reactions or are utilized by the body for specific functions.
Enzymes are essential for bodily functions.
Hormones: Communication and Regulation
Proteins create hormones, which facilitate communication between different areas of the body.
Hormones are secreted by cells and transported in the bloodstream to affect specific cells.
Hormones regulate metabolism, appetite, temperature, heartbeat, and breathing, among other bodily functions.
Not all hormones are proteins, but some are derived from protein.
Immune Function: Antibodies
Protein aids immune function through white blood cells, which are part of the immune system.
White blood cells produce antibodies, which are proteins that combat bacteria, toxins, or viruses.
Antibodies protect the body from illness and facilitate recovery.
Hemoglobin: Oxygen Transport
Proteins are essential to creating hemoglobin, which is a structure made out of protein.
Hemoglobin is a protein structure found in red blood cells that binds to oxygen, enabling oxygen circulation throughout the body.
Low protein consumption can decrease hemoglobin production, affecting oxygen circulation.
Hemoglobin consists of intertwined strains of string with yellow rings that bind to oxygen.
Adequate protein intake is important for maintaining hemoglobin levels and facilitating oxygen transport.
Energy Source (Last Resort)
Protein can be used as energy, but the body prefers to use it for other functions.
The body preserves protein due to its importance in various bodily functions.
Protein is primarily used for energy during starvation or prolonged exercise.
During prolonged exercise, only about 10% of energy needs are met through protein.
The body breaks down muscle to convert protein into energy during starvation.
Amino Acids: The Building Blocks of Protein
Proteins are constructed from 20 amino acids, which are the building blocks of protein.
Linking amino acids together constructs proteins for various functions like muscle building, hemoglobin production, antibody creation, and hormone synthesis.
Amino acids consist of an amino group, a carboxyl acid group, a central carbon, and a hydrogen atom.
The side chain (R-group) differentiates each amino acid, giving it unique properties.
The sequence and number of amino acids determine a protein's shape, size, and function.
Peptide Bonds: Linking Amino Acids
Amino acids are linked by peptide bonds formed when the carboxyl group of one amino acid combines with the amino group of another, releasing water.
Two joined amino acids form a dipeptide.
Three joined amino acids form a tripeptide.
Genetic Information and Protein Synthesis
Genetic information in DNA is expressed as protein.
A gene (segment of DNA) encodes information specifying the amino acid sequence for each protein.
Genes are protein recipes determining the order in which amino acids are bound together.
The body copies genes to construct proteins by reading the genes and joining amino acids in a specific order.
A defective or out-of-order amino acid can prevent the protein from performing its intended purpose.
DNA provides the blueprint for protein creation.
Chromosomes are made up of DNA; segments of DNA are called genes.
Essential vs. Nonessential Amino Acids
The body breaks down ingested protein into individual amino acids, rearranges them, and uses them in the body.
The body can manufacture some amino acids (nonessential), but others (essential) must be obtained from food sources.
There are nine essential and 11 nonessential amino acids.
Food Sources of Protein
Food sources of protein include meats, dairy products, seafood, soy, legumes, cereals, corn, and roots.
Animal protein contains all essential amino acids and is considered complete or high biological value protein.
Plant-based proteins may lack one or two essential amino acids, but a combination can provide equal value to animal protein (e.g., rice and beans).
Legumes lack certain amino acids, while cereals have plenty of the amino acids that legumes do not have.
** Protein in food provides calories per gram.Recommended intake is grams of protein per kilogram of body weight per day.
Active individuals may require more protein to repair cells.
Acceptable protein intake ranges from % to % of daily calories.
A Harvard analysis found no correlation between total protein intake and overall mortality.
Lack of essential amino acids can result in malfunction of the body's proteins.
The body does not store excess amino acids for later use, so they must be consumed daily.
Protein deficiency can lead to growth failure, muscle loss, decreased immunity, and weakening of the heart and respiratory system.
Healthy protein sources like beans, nuts, fish, or poultry can lower the risk of diseases and premature death.
Protein Supplements vs. Whole Foods
Protein supplements are commonly found in powder form, such as whey, soy, and casein protein.
Whey protein is water-soluble, contains a high range of protein, has less fat, and is a complete protein.
Protein powders offer quicker amino acid absorption than food due to partial breakdown.
Protein supplements may be more beneficial post-workout, but protein from food is generally sufficient during the day.
Protein powders have little to no fat content, which may be a downside due to the importance of fatty acids.
Protein supplements lack vitamins, minerals, carbohydrates, and healthy fats found in whole foods.
Protein should ideally come from whole foods unless there is a medical need or special reasoning.
Protein Quality and Bioavailability
Protein quality refers to how well amino acids from a certain food item can be absorbed (bioavailability).
High protein quality means high bioavailability of amino acids.
Food labels can be used to assess protein quality.
For high protein quality, grams of protein should be doubled in the percentage of daily value on the food label.
Animal products typically have high protein quality.
Plant-source protein items should be assessed for protein quality due to phytochemicals that may interact with absorption.
Phytochemicals in plant source items interact and inhibit the absorption of nutrients and amino acids.
If a food item has low protein quality, more must be consumed to meet amino acid needs.
Factors Influencing Protein Needs
Factors influencing protein needs include exercise intensity and duration, training status or fitness level, and injury status rehabilitation.
Exercisers need more protein than non-exercisers to repair broken-down muscles.
High-intensity or long-duration exercise further increases protein needs.
Novice exercisers need more protein during the first two weeks of exercise due to muscle damage.
More fit individuals need less protein due to greater movement efficiency.
Injured individuals or those recovering from surgery need more protein for repair and recovery of tissues and cuts.
Nitrogen Balance: Assessing Protein Intake
Nitrogen balance is a way to determine if protein intake is greater than protein output.
If an individual consumption is more than they are excreting it is considered good. On the other hand, if the body is losing more protein, then what is being consumed the body is gonna break down muscles or other form of protein for the necessity of amino acids.
Urea, created when protein is broken down, is used to determine nitrogen balance.
During protein breakdown, protein is broken down into amino acids. And for this amino acid to take place the nitrogen part must be removed or stripped.
When nitrogen part of amino acids is being removed it creates a substance called urea.
Urea is a way that the body removes nitrogen from amino acids, preventing toxicity.
Urea is created in the liver and filtered out by the kidneys, then excreted in urine.
To determine nitrogen balance, record protein intake and measure urea levels in urine to determine protein output.
Positive nitrogen balance means protein intake is greater than protein output indicating adequate protein intake.
Negative nitrogen balance means protein intake is less than protein output meaning inadequate protein intake.
It is ideal for individuals to have a positive nitrogen balance because protein is really important different function the don't want to be breaking them inside our body, but want to break down protein that is consumed through food sources.
High Protein Diets and Kidney Health
Research indicates that consuming larger amounts of protein does not cause extra work on the kidneys as long as extra protein intake is met with good consumption of water.
Good amount water intake and protein equals a healthy kidney.
Understand that as protein ingestion increases, it is very important that water consumption increases because the more protein a person consumes, then the more urea that is produced.
Water must be consumed to keep urea in solution and facilitate excretion.
Lack of water leads to the body pulling from water sources, which leads to dehydration. If this continues, then this could physiologically hurt and damage the body.
The kidneys will release urea through water in the form of urine.
Summary of Protein Functions and Metabolism
Protein functions include muscle building and repair, enzyme creation, and transportation.
Enzymes start chemical reactions, leading to products for further reactions or body functions.
Hemoglobin transports oxygen in red blood cells.
Protein is a non preferential energy source, it is just that it as so many that the body can do. With protein it doesn't want to use it as energy.
Amino acids, linked by peptide bonds, are the building blocks of protein.
DNA guides protein synthesis, with genes providing instructions.
There are essential and nonessential amino acids needs. Essential need to be in the diet and non essential doesn't need to be in the diet.
Complete protein sources (animal sources) have all essential amino acids, while incomplete sources (plant sources) require complementing.
Dietary guidelines provide recommendations, but individual needs vary based on exercise, fitness level, and injury status.
Nitrogen balance helps assess protein intake adequacy. Ideally in positive, because the body requires different amino acids for protein construction.