A recent analysis of 46 popular beverages finds that 78% of the drinks contain higher amounts of phosphorus than the reference values listed in nutritional databases – including some products that purport zero phosphorus.
And it’s not just the usual suspects, such as colas with phosphorus acid. Among 7 vitamin water flavors, for example, phosphorus amounts ranged from 0.9 to 261.4 mg per 8 fl oz. Iced teas likewise contained phosphorus amounts ranging from 3 to 105 mg.
For the Study of Dietary Additive Phosphorus on Proteinuria and FGF-23 (SODA-POP), investigators led by Alex R. Chang, MD, of Geisinger Health System in Danville, Pennsylvania, are examining the effect of phosphorus-based additives from foods and beverages on patients with early-stage kidney disease. They had a Pennsylvania laboratory measure the phosphorus content of popular beverages, including coffee drinks, artificial fruit punches, iced teas, lemonades, flavored waters, and sports drinks.
Nutritional databases, such as the USDA National Nutrient Databases and the Nutrition Data System for Research, “capture phosphorus content poorly in many popular beverages with phosphorus-based additives,” revealed Dr. Chang and colleagues in a research letter published in the American Journal of Kidney Diseases. Although the databases are updated regularly, they face several challenges, including keeping up with formula changes. At the moment, more than 85,000 unique food and beverage formulations exist in the marketplace, they noted. The FDA also does not require phosphorus to be listed on nutrition facts labels.
Discrepancies in the phosphorus content of foods and beverages make it difficult for dietitians to guide kidney disease patients on how to limit their phosphorus intake to protect their health. High serum phosphorus levels have been linked with cardiovascular disease and mortality. “Right now, even with the best nutrition databases, there isn’t a way to adequately plan an individual’s phosphorus intake,” Dr. Chang said. The simple but unsatisfying advice for patients appears to be avoid processed foods and drinks.
- National Kidney Foundation news release, June 17, 2015.
- Moser, M, et al. Am J Kidney Dis. June 2015;65(6):967-971; doi: 10.1053/j.ajkd.2015.02.330.