Phosphorus is required by the body for bone and teeth formation. Calcium alone can't build strong bones and tissues. New research shows calcium needs phosphorus to maximize its bone-strengthening benefits, and taking a lot of calcium supplements without enough phosphorus could be a waste of money.

Phosphorus allows proper digestion of riboflavin and niacin, aids in transmission of nerve impulses, helps your kidneys effectively excreting wastes, gives you stable and plentiful energy, forms the proteins that aid in reproduction, and may help block cancer. Researchers say it's the first time the two elements have been shown to be co-dependent for bone health. Both calcium and phosphorus are found naturally in dairy products, but most calcium supplements and calcium-fortified foods and beverages don't contain phosphorus.

More than half of all bone is made from phosphate, and small amounts are also used in the body to maintain tissues and fluids. Taking large amounts of calcium from supplements can interfere with phosphorus absorption. Women trying to prevent or treat osteoporosis typically take 1,000-1,500 mg of calcium a day in the form of supplements. Researchers found this amount of calcium can bind up to 500 mg of phosphorus, making it unavailable to the body.

Although this would present no serious problem for many people, it could impact women over 60 years of age who have diets that contain less than the National Academy of Sciences recommended daily allowance of 700 mg of phosphorus.

For these women, the usual calcium supplement, calcium carbonate, may block most of the absorption of phosphorus. If this happens, the calcium won't do much good because bone material consists of both calcium and phosphorus.
Researchers say their study shows both calcium and phosphorus are needed to support any increase in bone mass, and a calcium supplement that contains phosphorus would be preferable to one that provides calcium alone.

Phosphorus is the body's source of phosphate, which helps create and manage energy, synthesize protein, fat and carbohydrates, contract muscles, and maintain the body's fluid and electrolyte balance. It is also essential for stimulating hormone production and helping the body utilize the B vitamins. It combines with calcium to help form the latticework for strong bones and teeth. Over 80% of the body’s phosphorus is located in bone. A proper balance of magnesium, calcium, and phosphorus should be maintained at all times.

Not getting enough phosphorus can contribute to the following health problems: anxiety, bone problems, fatigue, irregular breathing, irritability, numbness, skin sensitivity, stress, teeth weakness, tremors, weakness, worry, and weight changes. You can also get malaise, stiff joints, and bone pain. It may also cause glucose intolerance, irregular heartbeat and difficulty breathing. Phosphorus deficiency results in bone loss just as calcium deficiency does. Phosphorus toxicity can result in twitching, jerking, and convulsions.

A diet consisting of junk food can have too much phosphorus and this effects the body's processing of calcium. It has also been found that vitamin D boosts the effectiveness of phosphorus. Magnesium helps in the absorption of phosphorus. Phosphorus speeds up healing, helps to prevent and treat osteoporosis, helps treat bone diseases such as rickets and prevents stunted or slow growth in children.

Phosphorus also helps to keep your mind alert and active, helps stimulate your glands to secrete hormones, and keeps your muscles and heart contracting regularly and smoothly. The recommended daily dietary intake of phosphorus set by the FDA is 1000-mg. The Food and Nutrition Board set the official scientific US RDA at 800-mg to 1200-mg. The phosphorus RDA is intended to equal the calcium RDA for any given individual. There are between 500,000- and 650,000-mg (500–650 g) of phosphorus in the healthy adult human body.

In “normal life”, there is only a very small possibility of a phosphorus deficiency because phosphorus is both abundant and widely distributed in most foods. The various food additives in processed foods are also major sources and may contribute up to 30% of total phosphorus in a diet based heavily on convenience foods. However, on a diet, there is a greater chance of phosphorus deficiency because less total food is eaten and very little of it is the usual type of “processed” food.

Phosphorus (as phosphate) is more efficiently absorbed in the small intestine than most other minerals. Between 50% and 90% is absorbed depending on the need. This is much higher absorption percentage than for either calcium or magnesium and further reduces the likelihood of phosphorus deficiency under normal conditions.

The kidneys easily control the blood phosphorus level and efficiently excrete any excess phosphorus. Therefore, under normal circumstances, phosphorus toxicity is also unlikely.