You need to eat foods with phosphorous to help your body do things like filtering waste and repairing tissue and cells. Too high or too low levels can cause problems like heart disease, joint pain, or fatigue.

Phosphorus is the second most plentiful mineral in your body after calcium. Most people get the amount of phosphorus that they need through their daily diets.

In fact, it’s more common to have too much phosphorus in your body than too little. Kidney disease or eating too much phosphorus and not enough calcium can lead to an excess of phosphorous.

However, certain health conditions or medications can cause phosphorus levels in your body to drop too low. Read on to learn about why you need phosphorous and what foods contain it.

Phosphorus is an important mineral in the body, making up around 1-1.4% of fat-free mass. It’s a crucial building block of bones, teeth, deoxyribonucleic acid (DNA), ribonucleic acid (RNA), as well as certain fats, proteins, and sugars.

Additionally, phosphorus is involved in making adenosine triphosphate (ATP), which is a source of energy for our cells, as well as activating enzymes, maintaining pH balance, and storing energy.

Most of the phosphorous in the human body is located in the bones, teeth, blood, and soft tissues. Many foods contain phosphorus, and we need to eat them to maintain a balance of the minerals in our bodies.

You need phosphorus to:

  • keep your bones strong and healthy
  • help make energy
  • move your muscles

In addition, phosphorus helps to:

  • build strong teeth
  • manage how your body stores and uses energy
  • filter out waste in your kidneys
  • grow, maintain, and repair tissue and cells
  • produce DNA and RNA — the body’s genetic building blocks
  • balance and use vitamins such as vitamin B and vitamin D, as well as other minerals like iodine, magnesium, and zinc
  • maintain a regular heartbeat

Most foods contain phosphorus. Foods that are rich in protein are also excellent sources of phosphorus. These include:

  • meat and poultry
  • fish
  • milk and other dairy products
  • eggs
  • legumes, especially lentils
  • nuts, especially cashews

When your diet contains enough calcium and protein, you’ll likely have enough phosphorus. That’s because many of the foods that are high in calcium are also high in phosphorous.

Some non-protein food sources also contain phosphorus. For example:

  • whole grains
  • potatoes
  • carbonated drinks (phosphoric acid is used to produce the carbonation)

Whole-grain versions of bread and cereal contain more phosphorus than those made from white flour.

However, phosphorus in nuts, seeds, grains, and beans is bound to phytate, making it harder to absorb. In addition, calcium can also bind and prevent phosphorus absorption.

A normal blood phosphorus level is 2.5-4.5 milligrams per deciliter (mg/dL). The amount of phosphorus you need in your diet depends on your age.

Adults need less phosphorus than children between the ages of 9 and 18, but more than children under age 8.

The recommended dietary allowance (RDA) for phosphorus is the following:

  • adults (ages 19 years and older): 700 mg
  • children (ages 9 to 18 years): 1,250 mg
  • children (ages 4 to 8 years): 500 mg
  • children (ages 1 to 3 years): 460 mg
  • infants (ages 7 to 12 months): 275 mg
  • infants (ages 0 to 6 months): 100 mg

Few people need to take phosphorus supplements. Most people can get the necessary amount of phosphorus through the foods they eat.

It’s rare to have too much phosphorus in your blood. The most common cause of too much phosphorus is kidney disease.

Other, less common, causes include getting too much phosphorous from food, overuse of phosphorous-containing laxatives or enemas, vitamin D intoxication, hypoparathyroidism, and various genetic deficiencies

Too much phosphate can be toxic. An excess of the mineral can cause diarrhea, as well as a hardening of organs and soft tissue.

High levels of phosphorus can affect your body’s ability to effectively use other minerals, such as iron, calcium, magnesium, and zinc. It can combine with calcium causing mineral deposits to form in your muscles.

Phosphorous deficiency can result from taking medications like insulin, corticosteroids, or antacids. It may also be caused by diabetes, alcohol use disorder (ASD), anorexia, starvation, and various genetic disorders.

Symptoms of low phosphorus can include:

  • joint or bone pain
  • loss of appetite
  • irritability or anxiety
  • fatigue
  • poor bone development in children

If you take these medications or have any of these health conditions, speak with your healthcare provider about whether you should eat foods high in phosphorus or take phosphorous supplements.

Most people get enough phosphorous from eating dairy, meat, poultry, and fish, as well as some plant foods like grains.

However, malnutrition and certain medical issues can leave you with either too much or too little phosphorus in your system, leading to symptoms like joint pain or fatigue, and contributing to heart disease and other health conditions.

Speak with your doctor if you experience any symptoms that might suggest a problem with phosphorous.