Vitamins, Minerals and Dietary Supplements
What is phosphorus?
Phosphorus is the second most abundant mineral in the body
behind calcium, making up approximately one percent of a person's
body weight. It is present in every cell in the body; however,
most phosphorus (85%) is concentrated in the bones and teeth.
Why do we need it?
Phosphorus takes part in almost every metabolic reaction
in the body. It is necessary for the conversion of dietary
carbohydrates, fats and proteins to energy, and forms part
of the adenosine triphosphate (ATP) molecule which acts as
a reservoir of energy in cells.
Phosphorus combines with calcium to form hydroxyapatite,
a major component of the structural part of bones and teeth.
It is also a component of some of the major building blocks
in the body, including RNA, DNA, and lipids found in the blood
and cell membranes..
How much phosphorus should I take?
According to the National Academy of Sciences, the recommended
daily allowance (RDA) for phosphorus is as follows:
- Adult men: 700 milligrams/day
- Adult women: 700 milligrams/day
- Children aged 7-10: between 500-1250 milligrams/day
- Infants: between 275-500 milligrams/day
- Pregnant/lactating women: 700 milligrams/day
What are some good sources of phosphorus?
Phosphorus is most prevalent in protein-rich foods such as
meat, poultry, cheese and milk; smaller amounts are found
in breads and cereals made from refined flour. Most soft drinks
contain large amounts of phosphorus, which may lead to excessive
What can happen if I don't get enough
Because phosphorus is so abundant in the average diet, deficiencies
are extremely rare. However, alcoholics and patients with
kidney or liver disorders may have difficulty absorbing phosphorus.
In addition, some antacids that contain large amounts of aluminum
may block phosphorus absorption.
Deficiency symptoms include weakness, loss of appetite, bone
pain, joint stiffness, irritability, numbness, speech disorders,
tremors and mental confusion. Red blood cells may die earlier
than normal, leading to anemia. White blood cells may also
be affected, which leading to reduced resistance to infection.
What can happen if I take too much?
High levels of phosphorus lead to calcium deficiency. This
loss of calcium may in turn increase the risk of disorders
such as kidney stones, osteoporosis and atherosclerosis. Excess
phosphorus intake can also prevent absorption of iron, magnesium
and zinc and decrease vitamin D levels, which may increase
the risk of bone disorders and cancer. A 1997 study involving
376 heart disease patients found a relationship between high
phosphorus levels and the severity of coronary heart disease.
- Recommended Dietary Allowances,
10th ed. Washington, D.C.: National Academy Press, 1989.
- Chan JM, et al. Dairy products, calcium, phosphorous,
vitamin D, and risk of prostate cancer. Cancer Causes Control
- Gomez-Ayala AE, et al. Effect of source of iron on
duodenal absorption of iron, calcium, phosphorous, magnesium,
copper and zinc in rats with ferropoenic anemia. Int J
Vitam Nutr Res 1997;67(2):106-14.
- Grenby TH, Saldanha MG. The use of high-phosphorus
supplements to inhibit dental enamel demineralization by ice
lollies. Int J Food Sci Nutr 1995;46:275-9.
- Calvo MS, Park YK. Changing phosphorus content of the
U.S. diet: potential for adverse effects on bone. J Nutr
Apr 1996;126:4, Suppl, 1168S-80S.
- Narang R, Ridout D, Nonis C, Kooner JS. Serum calcium,
phosphorus and albumin levels in relation to the angiographic
severity of coronary artery disease. Int J Cardiol
Jun 1997;60:1, p. 73-9.