What Is Phosphate?

Benefits, Side Effects, Dosage, and Interactions

Brussel sprouts, milk, nuts, tofu, and eggs

Verywell / Anastasia Tretiak


Table of Contents
View All
Table of Contents

Phosphorus is an essential mineral which plays a role in many functions of the body, including the structure of bone and teeth, muscle, and nerve conductions, filtering waste out of the body, DNA and RNA synthesis, and balancing the use of certain vitamins. Approximately 85% of the body's phosphorus is found in bones and teeth. The remaining 15% is distributed through the soft tissues.

In the body, phosphorus exists as phosphate, which is a salt of phosphorus. Doctors usually use the terms "phosphorus" and "phosphate" interchangeably.

Most of the phosphorus we need can be consumed by food, as it is plentiful in the diet. Very few people need to supplement with phosphate. In fact, some populations must monitor their phosphorus intake.

What Is Phosphate Used For?

Phosphorus is an essential mineral that has many roles. It's a structural component of bones and teeth and plays a role in building bone mass. It is also involved in DNA and RNA synthesis, assists in energy production and storage, and supports tissue growth during individual development or through pregnancy and lactation.

Eating adequate amounts of phosphorus is important in maintaining health and wellness.

The good news is that phosphorus is found in many foods including dairy, whole grains, nuts, seeds, certain meats, and fish. Generally, if you eat enough protein and calcium-rich foods, you are eating enough phosphorus. Phosphorus is also used as an additive in many processed foods and beverages. Most people do not have a problem getting the Recommended Daily Allowance (RDA) of phosphorus.

Foods that are rich in phosphorus
 Verywell / JR Bee Owner

Sometimes phosphate derivatives, such as phosphate salts, are consumed in the treatment of certain diseases. Always consult with your physician before starting any new regimen.

Treating Constipation

Sodium phosphate is found in over-the-counter enemas and other oral medications and is effective in the treatment of constipation. This class of laxatives helps promote a bowel movement by drawing water into the bowel, which softens the stool and makes it easier to pass. Laxatives containing sodium phosphates have label warnings, cautioning users to limit use to no more than once per day—the products should not be used for more than three days.

Equally important, consumers who do not have a bowel movement after taking an oral or rectal dose of a phosphate product should not take another dose of the product.

FDA is now warning that adults older than 55 and adults and children with certain health conditions should ask a healthcare professional before using these products because they may be at increased risk for harmful side effects. These new warnings are not currently in the Drug Facts label and apply to both adults and children

Treating Indigestion

Some antacids, used in the treatment of heartburn or indigestion, contain phosphate salts.

Treating High Calcium in the Blood

Certain phosphate salts may help to treat high levels of calcium. Additionally, potassium phosphate may help to prevent calcium kidney stones from forming in patients with elevated calcium in their urine.

Increasing Athletic Performance and Weight Loss

Phosphate salts, particularly sodium phosphate, have been tested as an ergogenic aid. This means that they can increase athletic performance. In one study, researchers found that supplementing with sodium phosphate increased performance in cyclists.

Sodium phosphate supplementation improved repeated-sprint and time-trial cycling efforts both one and four days post-loading in trained cyclists. Other studies have shown that sodium phosphates may increase performance in athletes; however, keep in mind that most studies were conducted with people who are already very athletically fit and the studies conducted were very small.

More research needs to be done in this area to determine the dose-effect as well as the long-term effects of phosphate supplementation.

Treating Osteoporosis

Some research shows that supplementing with potassium supplements that also contain calcium (such as tricalcium phosphate or dicalcium phosphate) may help to maintain strong bones and reduce the risk of osteoporosis. A review of the National Health and Nutrition Examination Survey (NHANES) literature suggests that high dietary phosphorus intake is associated with high calcium intake as well as improved bone health in some age/gender groups.

Whether or not you should supplement your diet with phosphorus and calcium depends on your overall dietary intake and should be discussed with your physician before implementing.

The type of phosphorus intake may also play a role in bone health. The average intake of phosphorus in the United States is well above the recommended dietary allowance. Inorganic phosphate additives, which are absorbed at a high rate, account for a substantial and likely underestimated portion of this excessive intake.

These additives have negative effects on bone metabolism and present a prime opportunity to lower total phosphorus intake in the United States. Further evidence is needed to confirm whether lowering dietary phosphorus intake would have beneficial effects to improve fracture risk.

Treating Refeeding Syndrome

There is some evidence to suggest giving sodium and potassium phosphate may help refeeding syndrome in those people who are extremely malnourished or have not eaten in an extended period of time.

Possible Side Effects

Side effects from phosphorus intake are rare because healthy kidneys help remove extra phosphate from your body to keep your blood levels in balance. However, certain types of medical conditions can make your body inefficient at removing extra phosphorus from the blood, which can result in a condition called hyperphosphatemia.

Hyperphosphatemia is typically accompanied by low levels of calcium which may result in muscle cramps, muscle spasms, and perioral (by the mouth) numbness or tingling. Other symptoms include bone and joint pain, pruritus (itchiness), and rash. Sometimes people with high levels of phosphorus experience feelings of fatigue, shortness of breath, nausea, vomiting, sleep disturbances, and in some cases, anorexia.

Some causes of high phosphorus levels include:

If you have any of these conditions, specifically chronic kidney disease, you may need to monitor your phosphorus intake. Discuss your diet with your healthcare provider and registered dietitian. People who have chronic kidney disease will need to have their blood monitored to keep a close eye on their phosphorus levels.

Keep in mind that phosphorus is not only in fresh foods, but is also found in sodas such as colas, fast food, processed meats and frozen foods, packaged cereals and other baked goods, and processed cheeses. However, keep in mind that processed foods such as these are best consumed in moderation for your overall health.

Brussel sprouts, sunflower seeds, and milk
Verywell / Anastasia Tretiak


According to the United States Department of Agriculture Food Survey, most Americans (around 96 percent) consume adequate daily amounts of phosphorus. Twenty percent comes from dairy sources such as milk and ice cream and others from foods such as bread, rolls, baked goods, chicken, vegetables, burritos, pizza, and more.

Some multivitamin/mineral supplements contain more than 15 percent of the current RDA for phosphorus. And since phosphorus is found in a variety of foods, rarely do we see phosphorus deficiency—with the exception of prolonged avoidance of food intake (near-total starvation).

The amount of phosphorus you need in the diet will depend on your age.

Phosphorus RDAs

According to the Institute of Medicine, the Recommended Dietary Allowances (RDA) and Upper Limit (UL) for phosphorus are:

  • 700 mg and 4,000 mg per day for adults, respectively, and
  • 1,250 mg and 4,000 mg/day in children and teenagers (ages 9 through 18)

Infants ages zero through six months need around 100 mg/day, children ages one through three years need 460 mg, and children ages four through eight years need 500 mg.

What to Look For

Because phosphorus is abundant in the diet, meeting your daily needs can be achieved by most people. When looking for foods rich in phosphorus, it's best to choose those that are minimally processed as this will help you to improve your health and optimize your nutrition.

Whole foods are naturally rich in vitamins, minerals, and other important nutrients, while processed foods can be full of added sodium, unhealthy fat, and sugar. Consider choosing foods such as:

  • Low-fat dairy: Milk, yogurt, cottage cheese, cheese, Kefir
  • Legumes: Beans, peas (dried is best as these contain less sodium)
  • Vegetables: Corn, Brussels sprouts
  • Nuts and seeds (unsalted)
  • Fruits: Dried fruit (look for unsweetened)
  • Whole grains: Oat bran muffins, quinoa
  • Protein: Salmon, eggs, chicken, turkey, oysters, sardines, tuna, lean red meat, tofu

Keep in mind that the phosphorus in vegetarian sources, such as beans, peas, nuts, and seeds, isn't absorbed as well as phosphorus from animal sources. This is because phosphorus in plant seeds is present as a storage form of phosphate called phytic acid or phytate. Humans lack enzymes to transform phytic acid into phosphorus.

The phosphorus found in whole grains that are incorporated into leavened bread is easier to absorb than cereals and flatbreads because bread contains yeasts that possess phytases (the enzyme that breaks down phytic acid into phosphorus).

Phosphorus that has been added to food in the form of an additive or preservative is used mostly for non-nutrient functions such as moisture retention, smoothness, and binding. This type of phosphorus is completely absorbed and is available in foods such as fast foods, ready-to-eat foods, canned and bottled beverages, enhanced meats, and most processed foods.

If you need to reduce your intake of phosphorus, avoiding phosphorus additives is a great place to start.

When you are reading packaged foods labels, avoid additives (if you need to watch your phosphorus intake) such as:

  • Dicalcium phosphate
  • Disodium phosphate
  • Monosodium phosphate
  • Phosphoric acid
  • Sodium hexameta-phosphate
  • Trisodium phosphate
  • Sodium tripolyphosphate
  • Tetrasodium pyrophosphate

You'll find out what is in the food you buy in the ingredient section of the nutrition facts label. Look for words that contain “PHOS” to find phosphorus additives in the food.

Common Over-the-Counter Prescriptions Drugs:

Phosphorus is also in many over-the-counter prescription drugs, including:

  • Fleet Phospho-soda EZ-Prep
  • K-Phos Neutral
  • K-Phos Original
  • OsmoPrep
  • Phospha 250 Neutral
  • Phospho-Soda
  • Visicol

When Would Someone Need to Supplement With Phosphorus?

Most people will not need to supplement with phosphorus unless they are trying to replace lost phosphorus by the body (which can happen due to a specific medical condition or when taking medications such as diuretic), to make the urine more acid, or to prevent the formation of kidney stones in the urinary tract.

Should your physician suggest you supplement with phosphorus, for whatever reason, they may recommend a tablet, capsule, or powder form. Most of the time, phosphorus will need to be mixed with water. Be sure to follow the instructions carefully to prevent side effects.

Also, be sure to notify your physician if you are taking any other supplements or medications as there can be drug/nutrient interactions.

A Word From Verywell

Phosphorus is an essential mineral that plays a role in various functions of the body including the structural component of bones and teeth. It is also involved in DNA and RNA synthesis, assists in energy production and storage, and supports tissue growth during individual development or through pregnancy and lactation. Phosphorus is so ubiquitous in various foods that deficiency is extremely rare. When looking for food sources, aim to choose whole foods, such as lean protein, legumes, fish, and low-fat dairy. Consult with your physician before making any diet changes or supplementing with phosphorus.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

By Barbie Cervoni MS, RD, CDCES, CDN
Barbie Cervoni MS, RD, CDCES, CDN, is a New York-based registered dietitian and certified diabetes care and education specialist.