PHOSPHORUS
85% of the total phosphorus exists as phosphates or esters in the body and is found chiefly in the skeleton and is combined with calcium. 14% of the phosphorus is found in intracellular tissues and 1 % is found in the extracellular fluid. Therefore phosphorus levels are a poor indicator of levels of phosphates in the body.
Phosphorus runs inversely to calcium levels in the body at a calcium to phosphorus ratio of 10 to 4. Therefore, calcium can be a great indicator for phosphorus as well.
As calcium levels increase in the serum, phosphorus levels decrease, and when calcium levels decrease phosphorus levels increase. In fact, causes of high calcium also cause low phosphorus. The controlling factor of phosphorus is parathormone (PTH), which is also the calcium-controlling factor. Phosphorus helps calcium through the cell membrane by increasing the permeability of the cell membrane via oxygen displacement.
1. Phosphorus is responsible for growth and development by way of:
✓ bonding
✓ polymer function
✓ hydration
✓ chemical transport, and
✓ buffering
2. Phosphorus is also responsible for bone formation
3. Phosphorus and metabolism of glucose
Phosphorus is also required for the metabolism of glucose via phosphorylation. Phosphorylation is when a phosphate radical promoted by glucokinase in the liver, or hexokinase in other cells captures the glucose and once inside the cells keeps it there. The exception to this occurs in the liver, the kidneys, and the intestinal epithelial cells.
Ingestion of carbohydrates causes phosphorus to enter RBC’s with glucose causing a reduction of serum phosphorus levels and lipids.
Phosphorus also works in the stomach to stabilize sugars and activate starches by the twofold process of phosphorylation.
Phosphorylation and its counterpart, dephosphorylation, turn many protein enzymes on and off, thereby altering their function and activity.
By altering pepsin/HCL levels phosphorus can:
a. Stabilize simple sugars-simple sugars are easily oxidized (combusted) before they reach the liver, resulting in low sugar levels. Pepsin stabilizes these simple sugars, so they can be transferred to the liver for storage.
b. Activation of starches- HCl is necessary to breakdown oily carbohydrates (grains), which are difficult to oxidize (combust). Thus making them readily available for oxidation.
The above two mechanisms establish an HCl-pepsin balance in the stomach for proper pH digestion.
The presence of both HCl and pepsin in the stomach are critical for preparing carbohydrates, as well as proteins for further digestion in the small intestines.
4. The regulation and maintenance of the acid-base balance in the body by maintaining glandular acidity.
5. The storage and transfer of energy from one part of the body to the other.
6. Used in the Production of phospholipids (90 % produced by the liver): lecithin, A cephalin, and sphingomyelin
Phospholipids are necessary for:
Proper brain function (sphingomyelins)
Phospholipids are a major constituent of lipoproteins which can affect function, formation and transport of these lipoproteins causing serious cholesterol abnormalities
Production of cell membranes
Thromboplastin production produced from A cephalin
7. Intracellular phosphorus is used for:
Energy transport formation of ATP from ADP and creatine phosphate via oxidative phosphorylation.
Major constituent of plasma membranes (phospholipids)
Major constituent of DNA and RNA (nucleic acids)
Calcium transport and osmotic fluid pressure
General nutritional considerations when phosphorus is high:
1. Patient should increase water intake
2. Reduce fat intake
3. Reduce Vitamin D intake if overdosing
4. An isotonic saline solution (sea salt) will decrease phosphorus levels
5. Also, decrease phosphorus in the diet and add calcium carbonate to your diet
General considerations when phosphorous is low:
1. Vitamin D deficiency
2. Calcium deficiency
3. Magnesium deficiency
4. Patient needs a high protein diet