You've probably consumed some potassium phosphate within the past few days — likely without even realizing it. This chemical is a common additive found in processed foods and nutritional supplements alike, but is it safe?
Potassium phosphate consists of the dietary minerals potassium and phosphorus in the form of phosphate. The U.S. Food and Drug Administration (FDA) categorizes potassium phosphate as "generally recognized as safe" (GRAS) as a food additive. This chemical, however, may pose health risks for people with kidney disease and certain other medical conditions. Check with your healthcare provider before taking supplements containing potassium phosphate to be sure they are safe for you.
Potassium Phosphate in Food
Potassium phosphate helps stabilize, thicken, and maintain the pH (acidity or alkalinity) and moisture in processed foods, according to the joint Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) expert committee on food additives. It also prevents fats from settling out of foods over time, which makes their texture and appearance more appealing.
Potassium phosphate effectively preserves and extends the shelf life of processed foods. It is a common food additive in canned fish, soup and vegetables, deli meats, sausages, ham, packaged baked goods, dairy products, tofu, cereal, crackers, frozen meals, fruit juices and condiments. In general, any processed food (including fast food) may contain a phosphate additive such as potassium phosphate.
Potassium Phosphate in Supplements
Multivitamin and mineral supplements typically contain phosphorus, sometimes in the form of potassium phosphate. Most American adults, however, do not require a nutritional supplement to meet the 700 milligrams recommended daily allowance (RDA) for phosphorus, as reported in a January 2014 article published in Advances in Nutrition. Most people's diets typically provide more than enough daily phosphorus — naturally found in meats, beans, fish, dairy and nuts — to meet the body's needs.
Many homeopathic and other over-the-counter remedies contain potassium phosphate as an active ingredient. These products, however, have not been approved or evaluated by the FDA. Their efficacy, therefore, remains scientifically unproven, particularly with regard to the potassium phosphate component.
Doctors prescribe potassium phosphate primarily to treat a phosphate deficiency, also known as hypophosphatemia. A low phosphate level can develop due to a variety of medical conditions, such as prolonged malnutrition, severe burns, vitamin D deficiency, alcoholism, electrolyte imbalances, certain hereditary disorders and underactive thyroid disease (hypothyroidism).
Potassium phosphate is sometimes prescribed to help prevent the formation of calcium kidney stones in people with a history of developing these. It can also help prevent or reduce skin irritation caused by urinary incontinence because it reduces the amount of ammonia in the urine.
Be sure to tell your doctor about all prescriptions and over-the-counter medications and supplements you take because potassium phosphate can interact with some substances, potentially causing serious side effects.
Phosphate food additives, including potassium phosphate, can contribute to the accumulation of excess phosphate in the body, or hyperphosphatemia. This most commonly occurs in people with kidney disease because reduced kidney function impairs their ability to excrete excess phosphate in the urine.
Phosphate additives are particularly problematic because they are more readily absorbed from the digestive system into the bloodstream than naturally occurring phosphorus in foods. According to a September 2016 Journal of Renal Nutrition study, the intestinal absorption rate for naturally-occurring phosphorus in food is 40 to 60 percent compared to a 90 percent rate for phosphate food additives.
Hyperphosphatemia can damage the blood vessels of the body, thereby increasing the risk of heart disease, stroke and other cardiovascular disorders. People with advanced kidney disease and hyperphosphatemia bear a significantly increased risk for heart disease and death, as noted in a June 2016 study in the Clinical Journal of the American Society of Nephrology.
Although the link between hyperphosphatemia and increased health risks has been studied primarily in people with kidney disease, there is some evidence that the condition also poses a risk for people with normal kidney function. A September 2018 study in the European Journal of Epidemiology involving involving more than 6,000 participants found an association between elevated phosphate levels and an increased risk of death and heart issues among men but not women.
However, additional research is needed to further clarify the possible health risks associated with elevated phosphate levels in the general population.
- FAO/WHO Food Standards, CODEX Alimentarius: "Tripotassium Phosphate"
- U.S. Food and Drug Administration: "Food Additive Status List"
- Advances in Nutrition: "Assessing the Health Impact of Phosphorus in the Food Supply: Issues and Considerations"
- Journal of Renal Nutrition: "Organic Phosphorus Versus Inorganic Phosphorus: Empowering Adult Kidney Patients with Nutrition Education"
- Clinical Journal of the American Society of Nephrology: "Phosphate Toxicity in CKD: The Killer Among Us"
- European Journal of Epidemiology: "Serum Phosphate Levels Are Related to All-Cause, Cardiovascular and COPD Mortality in Men"