A protein is a complex molecule that forms the basis of all life, and is composed of two or more amino acids. It is essential in the diet for growth, repair and replacement of tissue. Animal products (meat, fish, eggs, cheese) provide much protein in a form able to be used by the body. Vegetable proteins exist in peas, beans and other legumes, as well as in grains (and thus bread). If more protein is eaten than the body needs it will provide extra energy, but if not used it will be converted to fat and stored.
The recommended daily dietary intake is 2 mg per kilogram in infants, 20 mg in children, 60 mg in teenagers and 50 mg in adults.
The amount of protein present in a patient’s blood can be measured. The normal adult range is 60 to 80 g/L, but in a newborn infant it is only 45 to 75 g/L.
Low levels of blood protein are found with nephrotic syndrome (form of kidney failure), chronic kidney failure, malnutrition, children under 5 years, severe liver disease, overhydration (excess fluid in body) and a protein losing enteropathy (bowel disease in which excess protein is lost).
A high level of blood protein (proteinaemia) may occur with alcoholism, dehydration, multiple myeloma, lymphoma (lymph tissue cancer), autoimmune diseases, chronic liver disease, chronic infection, prolonged tourniquet while taking blood sample.
Blood contains many different types of protein, including albumin, globulin and fibrinogen.