Next to calcium, phosphorus is the most abundant mineral in the body, making
up about 1% of total body weight. Most of it is found in bones and teeth.
Phosphorus is present in the body as phosphates and, in addition to its role in
bone formation, it is vital to energy production and exchange. Phosphorus helps
in muscle contraction and nerve conduction. It aids kidney function and helps
maintain the body's pH balance. Phospholipids are fat molecules that play a role
in the maintenance of cell membranes. As a component of adenosine triphosphate
(ATP), phosphorus is involved in the body's primary metabolic cycles and in
protein synthesis for growth, maintenance, and repair of all body tissues and
cells, as well as in the production of the nucleic acids in DNA and RNA. It is
also necessary for the absorption of many vitamins and minerals, including
vitamin D, calcium, iodine, magnesium, and zinc.
The parathyroid hormone (PTH) regulates the metabolism of phosphorus and
calcium in the body. About two-thirds of phosphorus is absorbed from the
intestine, the rate depending to some extent on levels of calcium and vitamin D,
as well as the activity of PTH. While 85% of phosphorus is deposited in bones
and teeth, the remainder is found in cells and other body tissues. The blood
contains about 3.5 mg of phosphorus per 100 ml of plasma; total blood phosphorus
is between 30 and 40 mg. Together, calcium and phosphorus assure the formation
and maintenance of strong bones. The ideal dietary ratio of Ca:P is 1:1. A low
Ca:P ratio can lead to bone resorption as the body draws upon existing calcium
stores in the bone to pair with excess phosphorus. Not only is phosphorus
absorbed more efficiently than calcium, but people are likely to get more
phosphorus from their diets. The typical American diet has Ca:P ratios ranging
from 1:2 to 1:4. The growing consumption of soft drinks, which are buffered with
phosphates (as much as 500 mg in one serving), and high consumption of red meat
and poultry, which contain 10 to 20 times as much phosphorus as calcium, are
largely responsible for this imbalance. Decreased Ca:P ratios due to excess
dietary phosphorus impair calcium absorption, which contributes to bone loss,
osteoporosis, and periodontal disease. Low Ca:P ratios have also been associated
with an increased incidence of hypertension and elevated risk for colorectal
Phosphorus deficiency, or hypophosphatemia, is rare except in people affected
by certain diseases, in those receiving parenteral nutrition, or in those who
have received phosphate-binding agents that contain aluminum for extended
periods. It has been associated with anorexia, anxiety, apprehension, bone pain,
bone fragility, stiffness in the joints, fatigue, irregular breathing,
irritability, numbness, paresthesias, weakness, and weight change. In children,
decreased growth, poor bone and tooth development, and symptoms of rickets may
be signs of phosphorus deficiency. A greater concern for physicians is
hyperphosphatemia, or an excess of phosphorus. This is most often the result of
dietary imbalance. This has a negative result in terms of bone density and is of
particular concern to women. Acute or chronic renal failure may also lead to
hyperphosphatemia; in these cases restricting phosphorus intake to 800 to 1,000
mg is indicated.
Dietary sources of phosphorus include the following.
- Red meat and poultry
- Dried milk and milk products
- Wheat germ
- Hard cheeses
- Canned fish
- Soft drinks
Elemental phosphorus, a white or yellow waxy substance that burns on contact
with air (thus the term phosphorescent), is used in some homeopathic remedies.
However, because it is highly toxic, it is no longer used in medicine. Instead,
inorganic phosphates are used to treat phosphate deficiency. The following forms
- Dibasic potassium phosphate
- Monobasic potassium phosphate
- Dibasic sodium phosphate
- Monobasic sodium phosphate
- Tribasic sodium phosphate
Phosphorus is available over the counter in capsules. Because it is readily
available in a variety of foods, phosphorus supplementation is usually confined
to athletes who take it to reduce muscle pain and fatigue.
Phosphorus, by itself, is used in the treatment of only a few medical
conditions. Along with calcium, however, it can help in healing bone fractures
and in the treatment of osteomalacia, osteoporosis, and rickets. Regulating the
ratio of calcium-to-phosphorus intake through dietary sources can reduce stress
and alleviate problems like arthritis, which are related to calcium
Hypophosphatemia can cause an impaired response to insulin for which
supplementation with dibasic calcium phosphate (2 g tid with meals) has shown
good results. Phosphate supplementation is also used in the treatment of
diabetic ketoacidosis (DKA), and in constipation due to hypercalcemia. Mono- and
dibasic sodium phosphates may be used as mild laxatives administered by mouth or
rectally. Elemental phosphorus is used in homeopathic treatments for coughs and
some types of acute gastroenteritis.
|Dosage Ranges and Duration of
The U.S. RDA for phosphorus is 800 to 1,200 mg daily. The RDA for those up to
age 24 and during pregnancy and lactation is 1,200 mg daily.
Phosphates can be toxic at levels over 1 g/day, leading to diarrhea,
calcification of organs and soft tissue, and preventing the absorption of iron,
calcium, magnesium, and zinc. High levels of phosphorus can promote the loss of
calcium through nutritional hyperparathyroidism.
The overconsumption of foods high in phosphorus can drain calcium resources
and lead to reduced bone mass. American dietary habits, particularly the high
consumption of meat and soft drinks, makes low Ca:P ratios quite common. This
imbalance may be the source of the high incidence of osteoporosis in the U.S.
and other affluent nations where similar dietary habits prevail. Some
researchers have identified this as the likely mechanism contributing to low
bone mass in American women. Further retrospective studies are needed to
investigate this hypothesis. Low ratios of dietary Ca:P also reduce the efficacy
of treatments for osteoporosis. A 1986 experimental study of 158 females, aged
20 to 75, found that treatment of osteoporosis may in fact be fruitless when
dietary Ca:P ratios exceed 1:1.25. Patients need to be aware of the dietary
sources of both calcium and phosphorus so that they can take a more active role
in balancing these two elements in their diet.
No clinically significant interactions between phosphorus and conventional
medications are known to have been reported in the literature to
Anderson JJB. Calcium, phosphorus, and human bone development. J Nutr.
Berner YN, Shike M. Consequences of phosphate imbalance. Annu Rev Nutr.
Carey CF, Lee HH, Woeltje KF, eds. The Washington Manual of Medical
Therapeutics. 29th ed. New York, NY: Lippincott-Raven;
da Cunha DF, dos Santos VM, Monterio JP, de Carvalho da Cunha SF.
Miner Electrolyte Metab. 1998;24:337-340.
Kuntziger H, Altman JJ. Hyperphosphoremia and hypophosphoremia [in French].
Rev Prat. 1989;39:949-953.
Metz JA, Anderson JJB, Gallagher Jr PN. Intakes of calcium, phosphorus, and
protein, and physical activity level are related to radial bone mass in young
adult women. Am J Clin Nutr. 1993;58:537-542.
Mindell E, Hopkins V. Prescription Alternatives. New Canaan, Conn:
Keats Publishing Inc; 1998:495-496.
Reynolds JEF, ed. Martindale: The Extra Pharmacopoeia. 31st ed.
London: Royal Pharmaceutical Society; 1996:1181-1182, 1741.
Shires R, Kessler GM. The absorption of tricalcium phosphate and its acute
metabolic effects. Calcif Tissue Int. 1990;47:142-144.
Villa ML, Packer E, Cheema M, et al. Effects of aluminum hydroxide on the
parathyroid-vitamin D axis of postmenopausal women. J Clin Endocrinol Metab.
Walker LP, Brown EH. The Alternative Pharmacy. Paramus, NJ:
Werbach MR. Nutritional Influences on Illness: A Sourcebook of Clinical
Research. New Canaan, Conn: Keats Publishing Inc;
Copyright © 2000 Integrative Medicine
CommunicationsThis publication contains
information relating to general principles
of medical care that should not in any event be construed as specific
instructions for individual patients. The publisher does not accept any
responsibility for the accuracy of the information or the consequences arising
from the application, use, or misuse of any of the information contained herein,
including any injury and/or damage to any person or property as a matter of
product liability, negligence, or otherwise. No warranty, expressed or implied,
is made in regard to the contents of this material. No claims or endorsements
are made for any drugs or compounds currently marketed or in investigative use.
The reader is advised to check product information (including package inserts)
for changes and new information regarding dosage, precautions, warnings,
interactions, and contraindications before administering any drug, herb, or
supplement discussed herein.