Background

Phosphorus is an essential mineral found in many foods. In the diet and body, phosphorus usually binds to other minerals in the form of phosphate salts.

Phosphates are involved in cell structure, energy transport and storage, vitamin function, and many other essential processes in the body. Phosphate salts can act as laxatives by causing more fluid to be drawn into the intestines and making the gut push out its contents faster.

People use phosphate salts for bowel cleansing, low blood levels of phosphate, constipation, high blood levels of calcium, and heartburn. They are also used for athletic performance, osteoporosis, and many other conditions, but there is no good scientific evidence to support these other uses.

Safety Safety definitions

When taken by mouth: Phosphate salts are likely safe when consumed in the diet, or when supplements are used appropriately for a short time. Phosphate salts might cause side effects such as stomach upset, diarrhea, headache, and others.

Phosphate salts (as phosphorous) are possibly unsafe when taken in doses higher than 4 grams daily for adults 70 years and younger, or in doses higher than 3 grams daily for people over 70 years. Regular long-term use can upset the balance of phosphates and other chemicals in the body and should be monitored by a healthcare professional to avoid serious side effects.

When given as an enema (rectally): Phosphate salts are likely safe for most people when inserted into the rectum appropriately and short-term. But these products shouldn't be used more than once daily.

Special Precautions & Warnings:

Pregnancy and breast-feeding: Phosphate salts are commonly consumed in the diet. Phosphate salts are possibly unsafe when taken in amounts above the tolerable upper intake level (UL). The UL is 3.5 grams daily during pregnancy and 4 grams daily while breast-feeding.

Children: Phosphate salts are commonly consumed in the diet. Phosphate salts are possibly unsafe when taken in amounts that exceed the tolerable upper intake level (UL). The UL is 3 grams daily for children 1-8 years old and 4 grams daily for children 9 years and older.

Giving a sodium phosphate enema to children OVER 2 years of age is likely safe when no more than one dose is given every 24 hours. But it is likely unsafe to give more than one dose every 24 hours, or to give a sodium phosphate enema to children who are under 2 years of age.

Gastrointestinal (GI) conditions:: Sodium phosphate can cause damage to the intestines in some people. If you have an obstruction or have an inflammatory GI condition, avoid using sodium phosphate.

High levels of calcium in the blood (hypercalcemia):: Use phosphate salts cautiously if you have hypercalcemia. Too much phosphate could cause calcium to be deposited where it shouldn't be in your body.

High levels of phosphate in the blood: People with Addison's disease, severe heart and lung disease, kidney disease, thyroid problems, or liver disease are more likely to have too much phosphate in their blood when they take phosphate salts. Use phosphate salts only while under the care of a healthcare professional if you have one of these conditions.

Kidney disease: Use phosphate salts only while under the care of a healthcare professional if you have kidney problems.

Effectiveness

Dosing & administration

Phosphate (as phosphorus) is found in many foods, including meat, fish, eggs, and dairy products. Phosphate deficiencies are rare. The amount that should be consumed on a daily basis is called the recommended dietary allowance (RDA). For adults, the RDA is 700 mg. While pregnant or breast-feeding, the RDA is 1250 mg for those 14-18 years of age and 700 mg for those over 18 years of age. In children, the RDA depends on age. Speak with a healthcare provider to find out what type of product and dose might be best for a specific condition.

Interactions with pharmaceuticals

Bisphosphonates

Interaction Rating=Moderate Be cautious with this combination.

Bisphosphonate medications and phosphate salts can both lower calcium levels in the body. Taking large amounts of phosphate salts along with bisphosphonate medications might cause calcium levels to become too low.

Erdafitinib (Balversa)

Interaction Rating=Major Do not take this combination.

Erdafitinib increases the amount of phosphate in the blood. Taking phosphate salts along with erdafitinib can cause very high phosphate levels and serious side effects. Avoid phosphates when using erdafitinib.

Futibatinib (Lytgobi)

Interaction Rating=Major Do not take this combination.

Futibatinib increases the amount of phosphate in the blood. Taking phosphate salts along with futibatinib can cause very high phosphate levels and serious side effects. Avoid phosphates when using futibatinib.

Interactions with herbs & supplements

Calcium: Phosphate can bind with calcium. This reduces the body's ability to absorb phosphate and calcium. To avoid this interaction, phosphate should be taken at least 2 hours before or after taking calcium.
Iron: Phosphate can bind with iron. This reduces the body's ability to absorb phosphate and iron. To avoid this interaction, phosphate should be taken at least 2 hours before or after taking iron.
Magnesium: Phosphate can bind with magnesium. This reduces the body's ability to absorb phosphate and magnesium. To avoid this interaction, phosphate should be taken at least 2 hours before or after taking magnesium.

Interactions with foods

Taking phosphate with phosphate-containing foods and drinks might increase phosphate levels and increase the risk of side effects, especially in people with kidney problems. Phosphate-containing foods and beverages include cola, wine, beer, whole grain cereals, nuts, dairy products, and some meats.