There may be some health risks associated with consuming high amounts of phosphate additives, which are abundant in the food supply. But despite what some websites would have you believe, there is nothing unique about trisodium phosphate compared with other phosphate-containing food additives, such as pyrophosphate, dipotassium phosphate, hexametaphosphate, diammonium phosphate, and phosphoric acid. And no, the trisodium phosphate in foods is not a paint thinner.
Trisodium phosphate is approved as a food additive by the FDA and the European Union. This is food-grade trisodium phosphate—much-diluted, purified, and used in small amounts in food—not the technical-grade chemical found in paint thinner and many other products. What people may not realize is that food-grade forms of industrial chemicals are often used in the food supply—such as vinegar, which is diluted acetic acid, compared with highly concentrated acetic acid (glacial acetic acid), a caustic substance used in laboratory work that can severely burn the skin. Scaremongering websites are lumping food-grade trisodium phosphate with industrial use of the chemical.
Phosphates in food
Phosphates—a form of the essential mineral phosphorus—are some of the most common food additives, present in thousands of products, from packaged meats, chicken nuggets, and processed cheeses to baked goods, cereals, and cereal bars. Colas, both regular and diet, are a notable source, but other sodas and beverages, even some flavored waters, as well as some powdered drink mixes, may contain them too. Fast food is very high in phosphates. These additives are used by the food industry for all sorts of purposes—as leavening and anti-caking agents, stabilizers, flavor enhancers, emulsifiers, and moisture binders. Trisodium phosphate is used to adjust acid levels in cereals, for example. In canned tuna, phosphates help reduce crystal (struvite) formation.
One concern about phosphate additives in general is that they are very well absorbed—sometimes up to 100 percent—which can lead to elevated blood levels. In contrast, only 10 to 60 percent ofthe naturally occurring phosphates widely found in meat, poultry, seafood, dairy foods, nuts, seeds, beans, and whole grains are absorbed. And elevated blood levels have been linked in some (though not all) studies to a spectrum of health problems, notably cardiovascular events—not just in people with kidney disease, who have long been advised to limit their phosphorus intake, including phosphate additives, but also in healthy people. It’s thought that phosphates may damage blood vessels, impair endothelial function (which allows blood vessels to dilate), and promote calcification in blood vessels, all of which are linked to atherosclerosis.
For instance, a 2010 study in Arteriosclerosis, Thrombosis, and Vascular Biology found an association between blood phosphorus levels and cardiovascular disease and death, including in people with no heart disease at baseline. And a 2007 study in the Archives of Internal Medicine, which used data from the large ongoing Framingham study, found that high blood phosphorus levels predicted cardiovascular disease. Other studies have linked phosphates with stiff arteries, a thickening of the wall of the carotid artery (a major artery going to the brain), and increased risk of heart failure.
While the mineral phosphorus is needed for healthy bones, there is also accumulating evidence that excess phosphates may be contributing to low bone density and osteoporosis. Additional studies suggest that excess phosphates may contribute to type 2 diabetes, some cancers, and even obesity.
Many experts urge caution. The Center for Science in the Public Interest, a D.C.-based nonprofit consumer advocacy group, advises to “cut back” on phosphates. The Environmental Working Group offers similar advice.
Bottom line: More research is needed to confirm the potential adverse effects of phosphate additives. The European Food Safety Authority has been evaluating them and is expected to release its findings in late 2018. In the meantime, limiting processed foods, sodas, and “fast foods” is a sure way to reduce them in your diet. (Following a predominantly whole-foods, plant-based diet, limited in processed foods, is also the most healthful way to eat for many other reasons.) If you have chronic kidney disease, it’s particularly important to watch your intake, with the guidance of your health care provider or a registered dietitian.
Also see Phosphorus: Friend or Foe?