Phosphorus is a mineral that makes up 1% of a person's total body weight. It is the second most abundant mineral in the body. It is present in every cell of the body. Most of the phosphorus in the body is found in the bones and teeth.
The main function of phosphorus is in the formation of bones and teeth.
It plays an important role in how the body uses carbohydrates and fats. It is also needed for the body to make protein for the growth, maintenance, and repair of cells and tissues. Phosphorus also helps the body make ATP, a molecule the body uses to store energy.
Phosphorus works with the B vitamins. It also helps with the following:
- Kidney function
- Muscle contractions
- Normal heartbeat
- Nerve signaling
The main food sources are the protein food groups of meat and milk, as well as processed foods that contain sodium phosphate. A diet that includes the right amounts of calcium and protein will also provide enough phosphorus.
Whole-grain breads and cereals contain more phosphorus than cereals and breads made from refined flour. However, the phosphorus is stored in a form that is not absorbed by humans.
Fruits and vegetables contain only small amounts of phosphorus.
Phosphorus is so readily available in the food supply, so deficiency is rare.
Excessively high levels of phosphorus in the blood, although rare, can combine with calcium to form deposits in soft tissues, such as muscle. High levels of phosphorus in blood only occur in people with severe kidney disease or severe dysfunction of their calcium regulation.
Dosages for phosphorus, as well as other nutrients, are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board at the National Academies of Sciences, Engineering, and Medicine. DRI is a term for a set of reference intakes that are used to plan and assess the nutrient intakes of healthy people. These values, which vary by age and sex, include:
- Recommended Dietary Allowance (RDA): The average daily level of intake that is enough to meet the nutrient needs of nearly all (97% to 98%) healthy people. An RDA is an intake level based on scientific research evidence.
- Adequate Intake (AI): This level is established when there is not enough scientific research evidence to develop an RDA. It is set at a level that is thought to ensure enough nutrition.
Dietary Reference Intakes of phosphorus:
- 0 to 6 months: 100 milligrams per day (mg/day)*
- 7 to 12 months: 275 mg/day*
- 1 to 3 years: 460 mg/day
- 4 to 8 years: 500 mg/day
- 9 to 18 years: 1,250 mg
- Adults: 700 mg/day
Pregnant or lactating women:
- Younger than 18: 1,250 mg/day
- Older than 18: 700 mg/day
*AI or Adequate Intake
Diet - phosphorus
Mason JB, Booth SL. Vitamins, trace minerals, and other micronutrients. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 205.
Yu ASL. Disorders of magnesium and phosphorus. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 111.
Review Date 3/11/2021
Updated by: Meagan Bridges, RD, University of Virginia Health System, Charlottesville, VA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. Editorial update 09/29/2021.