Phosphorus is an essential mineral present in every cell in the body. It is a key component of bones, teeth, and adenosine triphosphate (ATP), the body’s main source of energy. It is also required for nerve, muscle, kidney and heart function.
Phosphorus exists in the body as phosphate, a compound that contains phosphorus and other substances, so phosphorus and phosphoric acid are often used interchangeably in the medical field.
Phosphorus is found in large amounts in many foods, including dairy products, fish, poultry, nuts, and beans. Phosphorus deficiency is rare, and most people don’t need to take supplements. However, some people, such as those with low phosphorus intake or those with certain medical conditions, may need phosphorus supplements.
Over-the-counter phosphorus supplements are different from phosphorus-based medications such as K-Phos, which are sometimes used to treat conditions like urinary tract infections and kidney stones.
Health by Design
Some people are at higher risk of developing a condition called hypophosphatemia. Hypophosphatemia In medical terms, hypophosphatemia refers to a blood phosphorus level below 2.5 milligrams per deciliter (mg/dL). Hypophosphatemia usually occurs as a result of inadequate dietary phosphorus intake, increased phosphorus excretion, or certain medical conditions.
Eating disorders and severe malnutrition
Nearly all diets contain enough phosphorus to maintain optimal levels. However, people who do not consume enough total calories, such as those with eating disorders such as anorexia nervosa or bulimia nervosa, may have low phosphorus levels and may require treatment with phosphorus supplementation.
For example, one study of 307 patients with anorexia nervosa (AN) or avoidant/restrictive eating disorder (ARFID) admitted to an eating disorder treatment center found that 44% of ARFID participants and 33% of anorexic participants had hypophosphatemia at the time of admission.
Severely malnourished people may also develop refeeding syndrome, a condition that occurs when nutrients are suddenly re-ingested after a long period of starvation, causing cells to absorb all available phosphate, resulting in severe hypophosphatemia.
Other medical conditions
People with medical conditions that cause intestinal malabsorption may also experience low phosphorus levels, as may people taking medications that bind phosphorus and increase its excretion from the body. One example is glucocorticoid drugs that are often used to treat inflammatory bowel disease (IBD).
Certain medical conditions and serious illnesses, such as chronic diarrhea, rare genetic disorders of phosphorus metabolism, hyperparathyroidism, renal tubular defects, and diabetic ketoacidosis, can also cause phosphorus deficiency.
Depending on the cause of low phosphorus levels, health care providers may give people phosphorus intravenously or prescribe oral phosphorus supplements to safely increase their phosphorus levels.
Some studies suggest that short-term phosphorus supplementation may improve exercise performance in endurance athletes, and some studies have found that phosphorus supplementation may improve power output, oxygen uptake, and aerobic capacity in cyclists and runners.
Phosphorus supplements may improve exercise capacity by increasing ATP availability and oxygen consumption by the heart.
For example, one study found that supplementation with 50 mg of trisodium phosphate per kilogram (kg) of lean body weight for six days decreased heart rate, increased oxygen consumption per heart beat, and increased stroke volume (the amount of blood pumped out of the left ventricle of the heart) during an exercise test performed in a low-oxygen environment.
Another study in cyclists also found that participants sensitive to phosphate supplementation significantly improved aerobic capacity by 3-5% after six days of trisodium phosphate, at 50 mg per kilogram (kg) of lean body mass per day. Other studies have shown that short-term phosphate supplementation can improve athletic performance in cyclists and runners.
However, research results are mixed. Some studies have found that phosphate supplementation does not provide any benefit to athletic performance. Therefore, it is unclear whether phosphate supplementation offers any significant benefit to athletes.
Phosphorus is found in both plant and animal foods. Some of the foods highest in phosphorus are:
- lentil: 356 milligrams (mg) per cup or 28% of the recommended daily value (DV)
- Low-fat yogurt: 245 mg per 6 oz serving or 20% of the recommended daily value
- Milk, 2%: 226 mg per cup or 18% DV
- salmon: 214 mg per 3 ounce serving or 17% of the recommended daily intake
- brown rice: 204 mg per cup or 16% of the recommended daily intake
- Mozzarella, skim: 197 mg per 1.5 oz serving or 16% of the recommended daily value
- Greenpeace: 188 mg per cup or 16% of your recommended daily value
- Chicken Breasts: 182 mg per 3 ounce serving or 15% of the recommended daily value
- Ground beef: 172 mg per 3 ounce serving or 14% of the recommended daily intake
Phosphorus is also found in small amounts in foods such as eggs, oats, sesame seeds, potatoes, and cashew nuts.
Phosphorus is abundant in the diet and is found in both animal and plant foods, so most people consume enough phosphorus to meet their daily requirements, even when following a more restrictive diet such as a vegetarian one.
Phosphorus is found in multivitamins and phosphorus-only supplements, but phosphorus-only supplements are less common. Phosphorus-only supplements that contain high doses of phosphorus are usually prescribed by health care professionals to treat low phosphorus levels and are not suitable for the general population.
The most common forms of phosphorus used in supplements are phosphate salts, such as dipotassium phosphate and disodium phosphate, both of which are relatively well absorbed by the body.
Most supplements, such as multivitamins, provide only small amounts of phosphorus per serving, usually 10% or less of the recommended daily intake, although some supplements, such as phosphorus-only supplements, may provide more than 100%.
If your healthcare provider determines that you have low phosphorus levels in your body, or if you have a medical condition that puts you at risk for developing a phosphorus deficiency, they may prescribe you an oral phosphorus supplement to safely boost your phosphorus levels. If prescribed, your healthcare provider will give you specific instructions about the dosage and how to take the supplement.
Do not take over-the-counter high-dose phosphorus supplements unless specifically prescribed and monitored by a healthcare provider.
Dose
The current Recommended Dietary Allowance (RDA) for phosphorus is 700 mg for adults aged 19 years and older. This is the total amount of phosphorus consumed from both food and supplements. Dosages of phosphorus supplements vary.
If you have been prescribed phosphorus for a medical condition or low phosphorus levels, your healthcare provider will recommend a total daily intake and dosing schedule, as phosphorus supplements are typically taken in multiple doses throughout the day.
Phosphorus supplementation, even in high doses, is usually safe for healthy people.
However, you should not take high doses of phosphorus supplements unless prescribed by a healthcare professional. High doses, such as more than 6,000 mg of sodium phosphate per day, can increase blood phosphorus levels. HyperphosphatemiaThe main side effects include calcification of certain tissues, including the kidneys, and changes in hormones that regulate calcium metabolism.
Hyperphosphatemia can also occur in people who are unable to excrete excess phosphorus in their urine, such as those with kidney disease. Normally, the kidneys excrete 90% of the daily phosphorus load, but people with kidney disease are unable to adequately excrete the excess phosphorus.
People with advanced kidney disease often need to limit foods high in phosphorus and avoid supplements that contain phosphorus to prevent phosphorus accumulation in the body. Several other medical conditions, such as hypothyroidism and genetic defects, can also cause hyperphosphatemia.
Phosphates, such as sodium phosphate, can also damage the intestines in people with inflammatory gastrointestinal diseases or intestinal obstructions.
People with these health conditions should not take phosphorus supplements unless specifically prescribed by their health care provider.
Potential Drug Interactions
Phosphorus supplements may interact with some medications, such as:
- Barbersa (erdafitinib): Erdafitinib is an anticancer drug that increases phosphate levels in the blood. Taking phosphate salts, such as dipotassium phosphate or disodium phosphate, at the same time as this drug can cause dangerously high phosphate levels.
- Bisphosphonates: Bisphosphonates are drugs that help prevent loss of bone density. Both bisphosphonates and phosphates can lower calcium levels in the body, and taking them together can cause calcium levels to become too low, which can be dangerous to your health.
Other medications may interact with phosphorus supplements. Consult your healthcare provider about potential interactions.
To support optimal absorption, phosphorus supplements should be taken at least two hours apart from other mineral supplements such as iron, calcium, and magnesium.
What to look for
Most people don’t need to take phosphorus supplements. Those with low phosphorus levels are usually treated with prescription medications.
However, when buying commercial supplements that contain phosphorus, it is important to choose products from a reputable company. When possible, it is best to buy supplements that are USP, UL, or NSF International certified. These independent organizations set strict standards for the quality and safety of supplements.
Can you get too much phosphorus?
You should not take dietary supplements that contain high concentrations of phosphorus unless specifically directed by a healthcare professional. Most healthy people get enough phosphorus in their diet and do not need phosphorus supplements to maintain healthy levels.
The tolerable upper intake levels (ULs), which are the maximum daily intakes of nutrients that are unlikely to cause harm, are currently set at 4,000 mg/day for adults aged 19-70 years and 3,000 mg/day for adults aged 71 years and older. The UL for pregnant women is set at 3,500 mg/day.
The UL for phosphorus applies to both foods and supplements, except that the UL does not apply to people taking phosphorus supplements prescribed and supervised by a healthcare provider.
Phosphorus supplements can have several side effects, most of which affect the digestive system. Here are some side effects you may experience when taking phosphorus supplements:
If you experience side effects while taking phosphorus supplements, contact your healthcare provider.
Phosphorus supplements may be prescribed for people who have low phosphorus levels due to a medical condition or reduced phosphorus intake. Typically, a healthcare professional will prescribe phosphorus for people with low phosphorus levels.
Phosphorus is also found in multivitamin and phosphorus-only supplements, but most people don’t need to take phosphorus in supplements because it’s found in many plant and animal foods.
Generally, healthy people do not need to supplement with phosphorus. However, if you are interested in taking a product that contains phosphorus, we recommend consulting with your health care professional to ensure it is a safe and appropriate choice for your health needs.
