Phosphorus | ||||||||
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- Why phosphorus is good for you
- Important phosphorus facts
- Groups at risk of phosphorus deficiency
- Symptoms of phosphorus deficiency
- Phosphorus and health
- Phosphorus in foods
- Phosphorus recommended daily intake (RDI)
- Phosphorus works best with
- Overdosage, toxicity and cautions for phosphorus
Why phosphorus is good for you
Phosphorus is an essential mineral that is required by every cell in the body for normal function. Phosphorus is found not just in the bones and teeth, but also in all cells of the body. Phosphorus is also part of DNA and RNA, so it is necessary for growth.
Phosphorus is very involved with bone and teeth formation as well as most metabolic actions in the body, including kidney functioning, cell growth and the contraction of the heart muscle.
The main inorganic component of bone is calcium phosphate salts while cell membranes are composed largely of phospholipids. While phosphorus assists the body in vitamin use (especially some B group vitamins), it is also involved in converting food to energy.
- Phosphorus can be found in the bones and muscles
- Phosphorus from nuts, seeds, and grains is about 50% less bio-available than phosphorus from other sources such as meat, chicken and dairy products
- Aluminum hydroxide used in antacids may interfere with the absorption of phosphorus but it is unlikely to cause a deficiency of phosphorus, as phosphorus is so abundant in foods in most diets
- Calcium and phosphorus must be balanced in the diet
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Groups at risk of phosphorus deficiency
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People in these groups at risk of deficiency should talk to a medical professional about phosphorus supplements BEFORE taking them.
Symptoms of phosphorus deficiency
Since phosphorus is so widespread in most food, dietary phosphorus deficiency is usually seen only in cases of near total starvation.
Inadequate phosphorus intake results in abnormally low serum phosphate levels (hypophosphataemia). The effects of hypophosphatemia may include loss of appetite, anemia, muscle weakness, bone pain, rickets (in children), osteomalacia (in adults), increased susceptibility to infection, numbness and tingling of the extremities, and difficulty walking. Severe hypophosphatemia may result in death.
Deficiency of this element is unusual but may have symptoms varying from painful bones, irregular breathing, fatigue, anxiety, numbness, skin sensitivity and changes in body weight. A ratio of 2:1 in the diet between phosphorus and calcium can cause low blood calcium levels.
If calcium is in short supply relative to phosphorus there may be increased risks of high blood pressure and bowel cancer.
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FOOD | AMOUNT | phosphorus (mg) |
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Yogurt, plain nonfat | 1 cup | 383 |
Lentils, cooked | ½ cup | 356 |
Fish, salmon, cooked | 85g | 252 |
Milk, skim | 1 cup | 247 |
Fish, halibut, cooked | 230g | 242 |
Beef, cooked | 85g | 173 |
Turkey, cooked | 85g | 173 |
Chicken, cooked | 85g | 155 |
Almonds | 30g | 139 |
Cheese, mozzarella; part skim | 30g | 131 |
Egg, cooked | 1 large | 104 |
Peanuts | 30g | 101 |
Bread, whole wheat | 1 slice | 64 |
Carbonated cola drink | 1 can (375ml) | 44 |
Bread, enriched white | 1 slice | 24 |
Phosphorus recommended daily intake (RDI)
RDA | lifestage | age | amount |
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INFANTS | 0-6mths 7-12mths |
100mg 275mg |
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CHILDREN | 1-3yrs 4-8yrs |
460mg 500mg |
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CHILDREN | 9-18yrs | 1250mg | |
ADULTS | 19-50yrs | 700mg | |
SENIORS | 51+yrs |
700mg | |
PREGNANT | <18yrs 19-50yrs |
1250mg 700mg |
|
LACTATING | <18yrs 19-50yrs |
1250mg 700mg |
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TOLERABLE UPPER LIMIT | lifestage | age | AMOUNT |
INFANTS | 0-6mths 7-12mths |
n/a* | |
CHILDREN | 1-8yrs | 3000mg | |
CHILDREN | 9-18yrs | 4000mg | |
ADULTS | 19-50yrs | 4000mg | |
SENIORS | 51-70yrs 71+yrs |
4000mg 3000mg |
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PREGNANT | all ages | 3500mg | |
LACTATING | all ages | 4000mg | |
Toxic Levels | >5,000mg |
The tolerable upper limits should only be taken for short periods and only under medical supervision.
* The tolerable upper limit for phosphorus for infants aged 0-12 months has not yet been determined due to a lack of data about the adverse effects in this age group. The only source of phosphorus intake should be from food (breast milk and/or baby formula).
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Overdosage, toxicity and cautions for phosphorus
Acute toxicity - Hyperphosphatemia, hypocalcaemia, hypomagnesaemia, laxative effect, tetany
Chronic toxicity - Bone re-absorption, calcification of heart and kidney, osteoporosis, hypocalcaemia, secondary parathyroidism and prevention of absorption of many minerals (ie calcium and chromium).
CAUTION
People who regularly use antacids that contain aluminium, should be very careful with phosphorus supplements - it is not advisable to take them together or at all.
Potassium supplements or potassium-sparing diuretics taken together with a phosphate may result in high blood levels of potassium (hyperkalemia). Hyperkalaemia can be a serious problem, resulting in life threatening heart rhythm abnormalities (arrhythmia). People on such a combination need to be sure their health care provider is aware of it, and have their blood potassium levels checked regularly.
references
- USDA National Nutrient Database - provides nutrient values for foods (accessed 5 January 2005)
- Osiecki, H. The Nutrient Bible. Bio-Concepts Publishing QLD, 2002
- Whitney EN, Cataldo DB, Rolfes SR. Understanding Normal and Clinical Nutrition, 6th Edition. Wadsworth/Thomson Learning, 2002