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Phosphorus is found in food, water, and living tissues in the form of phosphates. It is essential for tooth and bone health. Phosphorus is found in carbohydrates, fats, and proteins. 

NOTE: Phosphorus cannot be absorbed without vitamin D. The body draws a varying amount of phosphorus from foods depending on its requirements. 

Roles

What does phosphorus do? 

  • Plays a role in a number of chemical reactions in the cells;
  • Maintains normal acidity (pH) in the blood;
  • Stores and produces the energy the body needs;
  • Forms bones and teeth.

Needs

Recommended Dietary Allowance (RDA)
Age
Phosphorus (RDA) in mg/Day
Infants
0–6 months
100mg*
7–12 months
275mg*
Children
1–3 years
460mg
4–8 years
500mg
Preteens
9–13 years
1.250mg
Teens
14–18 years
1.250mg
Adults
Age 19 and over
700mg
Pregnant women
Age 18 and under
1.250mg
19–50 years
700mg
Nursing women
Age 18 and under
1.250mg
19–50 years
700mg

Source: DRI, Dietary Reference Intakes, 2006, p. 362.

*(AI) = Adequate intake for those two age groups.

Sources

Phosphorus is found naturally in foods in the form of phosphates. In food additives, it is found in the form of phosphate salts, which help preserve food, retain moisture and color, etc. 

Food Sources for Phosphorus: 

Foods
Serving
Phosphorus
Pumpkin or squash seeds, roasted
60ml (1/4 cup)
664mg
Beef liver, braised or sautéed
100g (3½oz)
485-497mg
Pollock, walleye, or swordfish, grilled
100g (3½oz)
477-482mg
Soybeans, cooked
250ml (1 cup)
421mg
Quinoa
 
421.5mg
Beef liver, cooked
100g (3½oz)
412mg
Sunflower seeds, grilled, oil-roasted, or dry
60ml (1/4 cup)
375-393mg
Lentils, cooked
250ml (1 cup)
356mg
Salmon, canned or grilled
100 g (3½oz)
256-354mg
Clams, canned or steamed
100g (3½oz) (8-12 medium)
338mg
Poultry offal, braised
100g (3½oz)
223-289mg
Halibut filets, grilled
100g (3½oz)
268-283mg
Plaice, flounder, haddock, or swordfish filets, grilled
100g (3½oz)
275-282mg
Regular ham, 11% fat, roasted
100g (3½oz)
281mg
Blue or Alaska king crab, canned or boiled
100 g (3½oz)
206-280mg
Plain yogurt, 0% to 4% M.F.
175g (3/4 cup)
201-259mg
Cow’s milk, 0% to 3.25% M.F.
250ml (1 cup)
261-247mg
Ricotta cheese, made with part skim or whole milk
125ml (1/2 cup)
205-240mg
Turkey with or without the skin, roasted
100g (3½oz)
198-207mg
Domestic duck with or without the skin, roasted
100g (3½oz)
156-203mg
Cottage cheese, 2% M.F.
125ml (1/2 cup)
180mg

Source: Health Canada, Canadian Nutrient File versions 2001b and 2005; U.S. Department of Agriculture (USDA), National Nutrient Database for Standard Reference.

Deficiency

Phosphorus deficiency is extremely rare since our requirements are met through diet. Deficiency may occur only in patients hospitalized for: 

  • Severe alcoholism;
  • Severe malnutrition (anorexia);
  • Metabolic acidosis.

Signs of phosphorus deficiency:

  • Anorexia;
  • Anemia;
  • Muscle fatigue and weakness;
  • Sensitivity disorders (tingling, pins-and-needles or burning sensation, numbness);
  • Cardiac problems;
  • Generalized weakness;
  • Bone pain and brittleness;
  • Rickets (emaciation in children), osteomalacia (softening of the bones due to defective bone mineralization in adults);
  • Irritability, possibly leading to confusion, delirium, coma;
  • Increased susceptibility to infection.

Adverse effects

Excessive doses of phosphorus (more than 4 g per day) may be due to phosphorus salt poisoning or a diet that combines food high in phosphorus and low in calcium. Increased phosphorus levels in the blood, called hyperphosphatemia, may occur in people suffering from: 

  • May occur in people suffering from;
  • End-stage chronic kidney failure;
  • Problems in parathyroid gland function (these glands secrete hormones that regulate calcium and phosphorus levels in the body).

Signs of excess phosphorus: 

  • Reduced calcium in the blood leading to reduced calcium absorption and increased risk of osteoporosis;
  • Hyperparathyroidism (abnormally high production of parathyroid hormone), causing reduced bone mass and calcification of certain soft tissues such as blood vessels, tendons, and muscles.

Cons-indications

  • People suffering from vitamin K deficiency;
  • People taking anticoagulants (e.g., Coumadin®);
  • Pregnant women and nursing mothers (who should avoid phosphorus supplements);
  • People suffering from kidney failure;
  • People with hormone problems tied to the parathyroid glands (gland hyperfunction).

Interactions

Natural health products or vitamin supplements: 

  • Calcium carbonate1 (therapeutic dose) may inhibit phosphorus absorption.

Medications: 

  • Antacids containing aluminum and magnesium1 may reduce phosphorus levels in the blood.

Additional information

1Take every 2 hours.

Speak with your pharmacist if you plan to take phosphorus supplements. Your pharmacist can help you choose the solution that’s best for you based on your health and any drugs you take.

Other names

Phosphorus, P