Sodium phosphate is an umbrella term that refers to multiple combinations of sodium (salt) and phosphate (an inorganic, salt-forming chemical).

Food-grade sodium phosphate is recognized by the U.S. Food and Drug Administration (FDA) as safe for consumption. It is often used as an additive in processed food manufacturing. It’s also an ingredient in many household products and medications.

For some people, sodium phosphate may be used to prepare the bowel prior to colonoscopy.

Sodium phosphate can be found in fast food, deli meat, processed meat, canned tuna, baked goods, and other manufactured foods. It serves a variety of functions:

  • It thickens food. It stabilizes the texture of processed foods, such as mashed potato mixes.
  • It cures meat and meat products. It helps to keep deli meats and bacon moist, avoiding spoilage.
  • It’s a leavening agent. It helps dough rise in commercially prepared cakes and breads and in cake mixes.
  • It’s an emulsifying agent. It acts as a stabilizer to keep oil and water mixed together in certain types of food, such as processed cheese.
  • It balances pH levels in processed food. It stabilizes the balance between acidity and alkalinity, extending shelf life and improving taste.

Food-grade sodium phosphate is categorized by the FDA as GRAS, which means “generally recognized as safe.” This may be because the amount of sodium phosphate added to processed food, is relatively low.

One study found that sodium phosphate, when used as a food additive, can impact health differently than naturally occurring phosphate. This is because it’s absorbed differently by the body. According to the abstract, high levels of phosphate may elevate mortality rates for the general public, as well as for those with kidney disease and cardiovascular disease. Researchers linked high phosphate levels to accelerated aging and vascular damage. The researchers recommended that people eat foods with naturally occurring phosphates, rather than those with added sodium phosphate.

Some athletes take sodium phosphate as a supplement to enhance performance. However, a study, reported in the International Journal of Sport Nutrition and Exercise Metabolism, found that supplementation with sodium phosphate did not improve aerobic ability in athletes.

Side effects from an overdose of sodium phosphate may include:

  • vomiting
  • headache
  • reduced urine output
  • bloating
  • abdominal pain
  • dizziness
  • irregular heartbeat
  • seizure

Talk to your doctor about your use of sodium phosphate, particularly if you take it as a supplement or eat a large amount of processed or fast food.

People with certain conditions should avoid taking this substance. These include:

  • kidney disease
  • intestinal tears or blockages
  • colitis, or slow moving bowels
  • heart failure
  • an allergy to sodium phosphate

Your doctor may also recommend reducing your intake if you are currently on certain medications. Prior to taking it, make sure to discuss your medication history, including which herbal supplements you use, with your doctor.

Foods with naturally occurring sodium phosphate include:

  • nuts and legumes
  • meat
  • fish
  • poultry
  • eggs

Foods that may have added sodium phosphate include:

  • cured meat
  • deli meat
  • fast food
  • processed foods, such as ready-to-eat meals
  • commercially prepared baked goods and cake mixes
  • canned tuna

Sodium phosphate is naturally occurring in many foods. It’s also added to foods to maintain freshness, alter texture, and achieve a variety of other effects. Sodium phosphate is considered safe by the FDA but should be avoided by certain people, including those with kidney disease. Make sure to talk to your doctor if you are concerned about your sodium phosphate intake or before using it as a supplement.