Why Is Phosphoric Acid Added to Soft Drinks?

Read the list of ingredients on your can of cola and you'll find phosphoric acid among them. Manufacturers add phosphoric acid to soft drinks as an acidifying agent. This substance appears in a variety of soft drinks, usually dark colas, giving them a tangy flavor. Phosphoric acid tends to stir up controversy, since it can have adverse effects on your health.

What Is Phosphoric Acid?

Phosphoric acid is a type of phosphorous commonly used as a food additive to enhance flavor or preserve freshness. Phosphorous, a mineral, originates from soil and water, but undergoes chemical processing to become a more stable element known as phosphoric acid. You need some phosphorous in your diet to support bone structure, produce and store energy, transmit genetic information and regulate your pH balance throughout your body.

How Much Do You Need?

You need 700 mg of phosphorous each day to support these basic functions. It is readily available in almost all foods, since all living organisms rely heavily on the mineral. Food additive sources of phosphorous, such as phosphoric acid in soft drinks, are not generally calculated as part of your phosphorous intake. If you drink soft drinks daily, you may consume too much phosphorous in the form of phosphoric acid. As of 2007, the average intake of phosphorous for women was 1,024 mg and for men 1,495 mg, according to the Linus Pauling Institute 1. One 12-ounce can of cola provides approximately 40 mg of phosphorous in the form of phosphoric acid. Ingesting large amounts of this mineral may have adverse effects on your health.

Health Effects

High levels of phosphorous in your blood is referred to as "hyperphosphatemia." Your kidneys work hard to regulate phosphorous in your body and eliminate any excess you consume, including in the form of phosphoric acid from soft drinks. This condition can lead to organ damage, most notably kidney damage. If you already have kidney disease or are at risk for developing it, drinking large amounts of soda containing phosphoric acid may be especially harmful. Having poor kidney function can lead to unusually high levels of phosphorous in your blood that lower calcium levels, increasing your risk of bone disease and brittle bones. Limit your phosphoric intake to 800 to 1,000 mg per day if you have kidney problems, suggests Dr. Erik P. Castle of the Mayo Clinic.

Other Options

Selecting soft drinks other than colas can help reduce your phosphoric acid intake. Clear soft drinks, such as ginger ale, lemon-lime soda or flavored seltzer, offer thirst-quenching flavor without the excess phosphoric acid. Root beer is another selection that doesn't typically contain phosphoric acid. Always read the ingredient list to ensure your soft drink selection is free of phosphoric acid, if you have a concern about your intake.