Phosphorus is also a component of the phospholipids, fat molecules essential to cell membranes; lecithin is the best-known phospholipid. It helps in fat emulsification and in other body functions. In the cell membranes, the phospholipids help maintain both fluidity and permeability, allowing the nutrients to pass in and out of the cells. The sphingolipids, involved in nerve conduction, also contain phosphorus. Phosphorus is combined with the B vitamins to assist their functions in the body; furthermore, phosphoproteins are contained in many enzyme systems.

In addition to its role in these processes and in skeletal growth and tooth development, phosphorus has a number of other functions. It helps in kidney function and acts as a buffer for acid-base balance in the body. Phosphorus aids muscle contraction, including the regularity of the heartbeat, and is also supportive of proper nerve conduction. This important mineral supports the conversion of niacin and riboflavin to their active coenzyme forms. As mentioned, parathyroid hormone regulates the phosphorus blood level and helps it carry out all these essential functions.

Uses: Phosphorus by itself is used in only a few medically significant conditions. It is not needed as frequently as calcium to balance the ratio between these two minerals. However, phosphorus has been used to treat many kinds of bone problems; it (along with calcium) helps in healing fractures by minimizing calcium loss from bones. It is used in the treatment of osteolmalacia, where there is decreased bone mineral content, and in osteoporosis, where total bone mass is decreased. Rickets has also been treated with phosphorus, as well as with calcium and vitamin D.

Rebalancing the calcium-phosphorus ratio in the diet can help reduce stress and many problems relating to calcium metabolism, arthritis being one example. Tooth and gum problems can be alleviated with dietary phosphorus, again in balance with calcium. Cancer research has revealed that cancer cells tend to lose phosphorus more readily than do normal cells, so phosphorus may be useful in the nutritional support of cancer patients; however, a high phosphorus-to-calcium intake is to be avoided.

Deficiency and toxicity:There is no known toxicity specific to phosphorus; however, high dietary phosphorus, as is found in a diet with meats, soft drinks, and other convenience foods, can readily affect calcium metabolism. Potential calcium deficiency symptoms may be more likely when the phosphorus intake is very high. A low calcium-to-phosphorus ratio in the diet increases the incidence of hypertension and the risk of colon-rectal cancer.

Problems of phosphorus deficiency are fairly uncommon, since it is so readily obtained in the diet; it is usually consumed in greater amounts than calcium and is readily absorbed. Relative deficiency of phosphorus can be caused by very high calcium intake or by taking a lot of antacids which can bind phosphorus. Aluminum, magnesium, and iron can interfere with phosphorus absorption. Low vitamin D intake can also lead to deficient body phosphorus.

Symptoms of phosphorus deficiency may include anorexia, weakness, weight loss, irritability, anxiety, stiff joints, paresthesias, bone pain, and bone fragility. Decreased growth, poor bone and tooth development, and symptoms of rickets may occur in phosphorus-deficient children. In adults, as mentioned, a low calcium-to-phosphorus ratio is most likely to generate problems. Osteoporosis (bone resorption) is often brought on by high phosphorus and low calcium intake. Other adult problems include skin disease, tooth decay, and even arthritis.