Phosphorus is a mineral that makes up 1% of a person's total body weight. It is the second most abundant mineral in the body. It is present in every cell of the body. Most of the phosphorus in the body is found in the bones and teeth. Phosphorus plays a role in many essential functions in the body.
The main function of phosphorus is in the formation of bones and teeth. It plays an important role in how the body uses carbohydrates and fats. It is also needed for the body to make protein for the growth, maintenance, and repair of cells and tissues.
Phosphorus forms a major part of cell buffer systems by producing phosphoric acid and phosphoric salts. Phosphorus also plays a key role in energy metabolism and the storage and usage of adenosine triphosphate (ATP), the energy that cells use to perform their functions. The ATP molecule requires three phosphate groups to perform its function in energy metabolism.
Phosphorus also plays an important part in how lipids are used in the body. Lipids in the cell wall of the body bind to phosphorus to form phospholipids, which give the cells their fluid-structure to allow the transport of compounds in and out of the cells. It is also needed for the body to make protein for the growth, maintenance, repair of cells and tissues, and synthesis of the nucleic acids DNA and RNA. Phosphorus assists in activation of many enzymes and B-vitamins through the attachment of phosphate groups.
Phosphorus is particularly important for the development of the nervous system and mental functions in children, as well as for the normal functioning of the nervous system. Phospholipids, phosphorus compounds, are necessary for the formation of a myelin sheath that protects nerve fibers. Phosphorus also helps with muscle contractions, and nerve signaling.
Phosphorus also helps with the kidney function, and normal heartbeat. Phosphorus also helps remove waste and repair damaged tissues.
Phosphorus plays an important role in improving the immune system and has positive effects against pathogenic microorganisms. Phosphorus serves the activities of the immune system and promotes a healthy microbial environment in the gastrointestinal tract and acts as a buffer to possible pathogens.
Phosphorus is readily available in food, making deficiency of the mineral rare. However dietary phosphorus deficiency can be found in cases of severe malnutrition, alcoholism, and anorexia, as well as in some preterm newborns and individuals with genetic phosphate regulation disorders.
Phosphorus deficiency is characterized by muscle weakness, confusion, increased risk of infection, poor appetite, and irritability. Deficiency of phosphorus in children leads to decreased growth, especially poor bone, and teeth development.
People with severe protein or calorie malnutrition can develop refeeding syndrome, also known as refeeding hypophosphatemia, within 2 to 5 days of starting enteral or parenteral nutrition because of the shift in metabolism from a catabolic to an anabolic state.
Causes of malnutrition that can lead to refeeding syndrome include chronic diseases, very low birthweight, cachexia, low body weight, anorexia nervosa, excessive alcohol intake, and chewing or swallowing problems. The effects of refeeding syndrome can include impaired neuromuscular function, hypoventilation, respiratory failure, impaired blood clotting, confusion, coma, cardiac arrest, congestive heart failure, and death.
Phosphorus is so readily available in the food supply that deficiency is rare. Excessively high levels of phosphorus in the blood, although rare, can combine with calcium to form deposits in soft tissues, such as muscle. High levels of phosphorus in blood only occur in people with severe kidney disease or severe dysfunction of their calcium regulation.
Hyperphosphatemia can lead to calcium precipitation into soft tissues, especially in patients with chronic kidney disease. Soft-tissue calcification in the skin is one cause of excessive pruritus in patients with end-stage renal disease who are on chronic dialysis. Soft-tissue calcifications are common among patients with chronic kidney disease; they manifest as easily palpable, hard, subcutaneous nodules often with overlying scratches. Imaging studies frequently show vascular calcifications lining major arteries.
Interactions with Medications
Phosphorus can interact with certain medications, and some medications can have an adverse effect on phosphate levels.
Antacids that contain aluminum hydroxide bind phosphorus in the intestines, and their chronic use for 3 months or longer can therefore lead to hypophosphatemia. These drugs can also aggravate existing phosphate deficiency. Antacids containing calcium carbonate also decrease intestinal absorption of dietary phosphorus.
Some laxatives contain sodium phosphate, and ingesting these products can increase serum phosphate levels. These products are potentially dangerous if more than recommended doses are taken, especially in people with kidney disease, heart disease, or dehydration.
Food Sources of Phosphorus
Most people get enough phosphorus through their diet. However, people with certain health conditions, such as kidney disease or diabetes, may need to adjust their phosphorus intake.
Most people get enough phosphorus in their diet, especially if they eat plenty of foods that contain protein and calcium.
Most protein-rich foods are excellent sources of phosphorus. These foods include chicken, turkey, seafood, seeds, low fat dairy products, such as yogurt and cottage cheese, and nuts.
Other foods that are less high in protein may also be good sources of phosphorus, but the body does not absorb the phosphorus in these foods as easily. These include garlic, potatoes, whole grains, broccoli, and dried fruit.