Phosphorus: Health Benefits and Dietary Sources
Phosphorus is an essential mineral that binds together with calcium to make strong bones and teeth. As a result, 85% of this mineral in the body is found in the bones and teeth. In fact, phosphorus happens to be the second most plentiful mineral in the human body after calcium, making up 1% of the body weight.
This mineral is also an important component of cell membranes and DNA and is thus necessary for the growth, repair and maintenance of all cells and tissues and critical to brain health. Its other important roles include breaking down carbohydrates and fats, assisting in the production and storage of energy, playing a vital role in removing the body waste, relieving pain and maintaining a healthy balance of other nutrients such as calcium, iodine, iron, magnesium, zinc and vitamin D and thus also maintaining a proper pH balance.
The recommended dietary allowance of phosphorus for adults (male and female) is 700mg (0.7 gram) per day, while the tolerable upper intake level is 4,000mg (4 grams) per day. Pregnant women and seniors (70 years and older) should not get more than 3,500mg and 3.000mg of phosphorus per day, respectively. Our modern diets typically provide more than the recommended dietary allowance because phosphorus is also present in food additives found in many processed foods and popular soft drinks.
Phosphorus is easily absorbed from various foods (except for grains, legumes and seeds) and beverages, so deficiency is rare. Deficiency usually only occurs in patients with renal phosphorus wasting, diabetes, conditions that cause poor nutrient absorption and in chronic alcoholics. The most common symptoms of phosphorus deficiency (hypophosphatemia) include lowered appetite, muscle weakness, anemia, compromised immune system, tingling of the extremities, stiff joints, bone pain and fragility and difficulty walking.
Phosphorus overdose in a healthy individual is rare just like its deficiency. High serum levels of phosphorus (hyperphosphatemia) usually only occur in people with kidney problems and those who consume too little calcium. The main symptom of phosphorus toxicity are cardiovascular problems. This is due to imbalance between phosphorus and calcium which may cause abnormal deposition of calcium phosphate in soft tissues and eventually lead to a loss of bone density (osteoporosis).
Dietary Sources of Phosphorus
Phosphorus is best absorbed from high protein foods such as meat, poultry, fish, shellfish, eggs, milk and dairy products. It is also available in high fiber foods such as grains, legumes and nuts but its absorption from these foods is poor. Smaller amounts of phosphorus can be also found in certain fruits and vegetables. In addition, this mineral is present in the form of phosphoric acid in many carbonated beverages as well as in the form of phosphorus-based additives used in processed foods.
Phosphate supplements are available but should only be taken by patients who cannot get enough phosphorus from their diet due to a disease that is causing poor absorption. Supplementation should help prevent problems with bones including rickets, osteoporosis and osteomalacia. However, phosphates may interfere with certain medications. Therefore, patients should only take phosphate supplements when prescribed by their doctor.