Protein – Functions, Requirements and Food Sources
Proteins are essential macromolecules made of amino acids that perform countless vital functions in the human body, from building tissue to supporting the immune system.
Save 15% with MUND15Wissenswertes über "Protein"
Proteins are essential macromolecules made of amino acids that perform countless vital functions in the human body, from building tissue to supporting the immune system.
What Are Proteins?
Proteins are large, complex biological molecules composed of chains of amino acids. Together with carbohydrates and fats, they form the three major macronutrients essential for human life. The human body contains thousands of different proteins, each performing specific and indispensable functions.
Structure and Composition
Proteins are built from 20 different amino acids linked together by peptide bonds. Of these, 9 are considered essential – meaning the body cannot synthesize them on its own and must obtain them through diet. The three-dimensional shape, or folding, of a protein chain determines its biological function.
Functions in the Human Body
- Structural role: Proteins such as collagen and keratin provide the framework for skin, bone, hair, and nails.
- Enzymatic role: Enzymes are proteins that catalyze and regulate biochemical reactions throughout metabolism.
- Transport role: Hemoglobin carries oxygen in the blood; other proteins transport hormones and nutrients.
- Immune function: Antibodies are proteins that identify and neutralize pathogens such as bacteria and viruses.
- Regulatory role: Hormonal proteins like insulin regulate blood glucose levels and other metabolic processes.
- Energy source: When needed, the body can use proteins for energy (approximately 4 kcal per gram).
Dietary Sources
Proteins are found in both animal and plant-based foods. Key sources include:
- Animal sources: Meat, fish, eggs, and dairy products – all providing complete proteins with all essential amino acids.
- Plant sources: Legumes (lentils, beans, chickpeas), tofu, tempeh, nuts, seeds, and whole grains – often requiring combination to cover all essential amino acids.
The biological value of a protein reflects how efficiently it can be converted into body protein. Egg protein serves as the reference standard (biological value = 100).
Recommended Daily Intake
The World Health Organization (WHO) recommends a minimum protein intake of 0.8 g per kilogram of body weight per day for healthy adults. Requirements are higher for pregnant and breastfeeding women, athletes, older adults, and individuals recovering from illness or surgery.
Protein Deficiency
Inadequate protein intake can lead to serious health consequences, including muscle wasting, impaired immune function, delayed wound healing, hair loss, and edema (fluid retention). In severe cases, especially in children in low-income countries, protein deficiency can result in kwashiorkor, a life-threatening form of malnutrition.
Excess Protein and Risks
Chronically high protein intake may place additional strain on the kidneys, particularly in individuals with pre-existing renal conditions. In otherwise healthy people, excess protein is metabolized and used for energy or converted to fat. A balanced intake as part of a varied diet is generally recommended.
Clinical Relevance
Specific proteins play a key role in clinical diagnostics. For example, C-reactive protein (CRP) is a marker of inflammation, while albumin levels reflect nutritional status and liver function. Many modern medications, including insulin and monoclonal antibodies, are themselves protein-based therapeutics.
References
- World Health Organization (WHO): Protein and amino acid requirements in human nutrition. WHO Technical Report Series 935, Geneva 2007.
- Berg JM, Tymoczko JL, Stryer L: Biochemistry. 9th Edition, W.H. Freeman and Company, New York 2019.
- Deutsche Gesellschaft fur Ernahrung (DGE): Reference Values for Nutrient Intake – Protein. 2nd Edition, Bonn 2019.
Verwandte Produkte
For Healthy Oral Flora & Dental Care
Formulated lozenges with Dentalac®, probiotic lactic acid bacteria, and Lactoferrin CLN®
For your universal protection
As one of the most valuable proteins in the body, lactoferrin is a natural component of the immune system.
For your iron balance
Specially formulated for your iron balance with plant-based curry leaf iron, Lactoferrin CLN®, and natural Vitamin C from rose hips.
Best-selling products
For your universal protection
As one of the most valuable proteins in the body, lactoferrin is a natural component of the immune system.
For your iron balance
Specially formulated for your iron balance with plant-based curry leaf iron, Lactoferrin CLN®, and natural Vitamin C from rose hips.
For Healthy Oral Flora & Dental Care
Formulated lozenges with Dentalac®, probiotic lactic acid bacteria, and Lactoferrin CLN®The latest entries
3 Posts in this encyclopedia categoryMoist Wound Care
Basal Metabolic Rate
Hysterosalpingography
Most read entries
3 Posts in this encyclopedia categoryMagnesiumcarbonat
Cologne list
Calorie content
Related search terms: Protein + Proteins + Proteine