Carbonated drinks such as soda pop dominate the landscape of commercially made beverages for unknown reasons. Why fizzy drinks, which are mildly painful to swallow and trigger bloating, are so appealing to people is a mystery and certainly a testament to clever marketing. In addition to the fizz, carbonated drinks also contain various acids, particularly phosphoric acid, which are linked to some health dangers.
Acids in Carbonated Drinks
Acids are added to most drinks, including carbonated ones, for three main reasons: as a disinfectant, preservative and taste enhancer. Acids kill most germs, which prevents the beverages from spoiling and increases their shelf-life. Acids are also sour, which contributes taste sensations. The most prevalent acids added to carbonated drinks are carbonic, phosphoric and citric acids. Carbonic acid forms from dissolved carbon dioxide, which makes carbonated drinks fizzy. Phosphoric acid is commonly added to colas to produce a sharp or crisp flavor, but also to deter mold and bacteria from feasting on all the added sugar. Citric acid comes from citrus fruit, and it’s commonly added to tart, fruit-flavored drinks. Less commonly added to carbonated drinks are malic and fumaric acids.
The acids commonly added to carbonated drinks are corrosive to the hard enamel that coats and protects the softer crowns of your teeth. The added sugar in soda pop, especially colas, also creates an acidic environment in your mouth and promotes the formation of cavities, but phosphoric acid is the most damaging compound to enamel. The pH scale is used to measure acidity, with lower numbers representing stronger acids. The pH level of your stomach acid is near 3.0, whereas the pH of many colas measures about 2.5. The sugar and various acids within many carbonated drinks wreak havoc in the mouth via tooth erosion, cavities, decay, gum infection and bad breath.
Phosphorus is an essential mineral for strong bones, but an imbalance of it compared to calcium leads to problems. Phosphoric acid breaks down into phosphorus in your body, and if too much of it circulates in your blood it attracts calcium from your bones in a process called mineral leaching or demineralization. Chronic demineralization, for many months or longer, is strongly linked to higher risks of bone fractures and the development of osteoporosis. Carbonic and citric acids are not directly linked with this phenomenon, although carbonated drinks often replace milk, water and natural fruit juices in people’s diets, which does have a negative impact on bone health and health in general.
High levels of phosphorus in the blood also damage the kidneys. Your kidneys are responsible for filtering and excreting excess phosphorus, so high phosphorus consumption can overwork them. Furthermore, the calcium and other minerals that excess phosphorus pulls into the bloodstream can clog the kidneys and lead to the formation of kidney stones. Multiple studies have shown that people who consume two or more colas daily have significantly higher risk of developing kidney stones and kidney dysfunction compared to those who don’t drink colas. Again, it’s the phosphoric acid that’s the problem, not the carbonic or citric acids.
- Nutritional Sciences for Human Health; Stanislas Berger et al.
- Public Health Nutrition: From Principles to Practice; Mark Lawrence and Tony Worsley
- Human Biochemistry; Charles Dreiling
- Contemporary Nutrition: Functional Approach; Gordon M. Wardlaw et al.
Sirah Dubois is currently a PhD student in food science after having completed her master's degree in nutrition at the University of Alberta. She has worked in private practice as a dietitian in Edmonton, Canada and her nutrition-related articles have appeared in The Edmonton Journal newspaper.