BABYMINDER – Proteins in the human body consist of 20 amino acids—the basic building material of life, the primary component of every cell in the body. Amino acids strung together in complex formations build and maintain body tissue. Blood cells, muscle, nerves, connective tissue and skin care are all built of protein.[pq]In a healthy body, the amount of protein intake exceeds the amount of protein taken out—there are more tissues built than broken down.[/pq]
This is normal during periods of rapid growth in childhood and adolescence.
Long-term protein deficiency leads to retardation of growth. Its effects may not be immediately evident but may soon result in muscle loss and weakness, impairment of body organs, and low resistance to infection and other diseases.
If more protein is consumed than is needed, the body doesn’t bulk up in more muscle—the excess is broken down and its components stored as fat. Excess protein can also bring uremia or accumulation of urinary waste products in the blood, acidosis or an abnormal increase in the acidity of body fluids and hyperammonemia—a metabolic disturbance marked by high levels of ammonia in the blood.
Functions of proteins
- Tissue builder. Proteins build and make up the cell bulk of nerves, musles, brain and other internal organs including hair, skin and nails. Proteins are also a basic component of blood plasma, enzymes, hormones, and other regulatory substances.
- Energy supplier. Proteins serve as back up source of energy to the body’s chief source of fuel, carbohydrates.
- Metabolic enabler. Proteins are key components of hemoglobin, oxygen carrier of red blood cells. With oxygen, cells can perform various metabolic processes. Proteins also produce agents that control hormones and other forms of metabolism, such as digestion.
Sources, recommended intake
Proteins come from plants and animals—small amounts of vegetable protein can greatly enhance the value of vegetable proteins. Protein-rich plant sources include chickenpeas or garbanzos, bean curd, peanut butter, munggo and other dried beans, cereals, and nuts. Animal-derived protein sources include milk, meat, liver, heart, kidney, poultry, eggs, fish, and shellfish.
Dietary guidelines recommend safe daily intake of proteins: 16 grams for children one to three years; 43 grams for children seven to nine years; 54 grams for boys 10 to 23 years; and 49 grams for girls 10 to 12 years.