Phosphorus
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