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Improving Estimates of Phosphorus Additive Content: Manufacturers Needed

      Dietary phosphorus restriction is a common feature of medical nutrition therapy for patients with chronic kidney disease or end-stage renal disease.

      Academy of Nutrition and Dietetics. Nutrition Care Manual®. March 30, 2016. Available at: http://www.nutritioncaremanual.org. Accessed June 13, 2016.

      Mean phosphorus intake in the general American population is estimated at 1655 mg/day for men and 1190 mg/day in women as reported by 2009-2010 National Health and Nutrition Survey data.
      • Calvo M.S.
      • Moshfegh A.J.
      • Tucker K.L.
      Assessing the health impact of phosphorus in the food supply: issues and considerations.
      Although specific limits may be individualized, a maximum of 800-1000 mg of dietary phosphorus per day is commonly used in clinical practice.

      Academy of Nutrition and Dietetics. Nutrition Care Manual®. March 30, 2016. Available at: http://www.nutritioncaremanual.org. Accessed June 13, 2016.

      Restricting dietary phosphorus can be quite challenging, particularly for patients on dialysis who have increased protein requirements. Naturally occurring sources of phosphorus include dairy products, fish, poultry, meat, and whole grains. Patients are often encouraged to consume these types of foods as part of a healthy diet, and thus, giving advice to reduce phosphorus from natural sources becomes challenging.
      Adding to the difficulty of restricting dietary phosphorus is the increasing contribution of phosphorus from food additives.
      • Leon J.B.
      • Sullivan C.M.
      • Sehgal A.R.
      The prevalence of phosphorus-containing food additives in top-selling foods in grocery stores.
      In a recent study examining phosphorus content of the most popular food items purchased in Northeast Ohio, Leon et al. found that 44% of products contained phosphorus additives. Furthermore, a diet composed of products with phosphorus additives contained 67 ± 14 mg phosphorus/100 g more than a comparable diet composed of products without phosphorus additives. Moreover, although only 40%-60% of naturally occurring phosphorus is typically absorbed, up to 80%-100% of phosphorus additives may be absorbed.
      • Leon J.B.
      • Sullivan C.M.
      • Sehgal A.R.
      The prevalence of phosphorus-containing food additives in top-selling foods in grocery stores.
      Currently, manufacturers are not required to report phosphorus on nutrition facts panels. Several studies have demonstrated higher phosphorus content in foods containing phosphorus additives and inaccuracies in nutritional databases' reporting of the phosphorus content of these processed food and beverage products.
      • Leon J.B.
      • Sullivan C.M.
      • Sehgal A.R.
      The prevalence of phosphorus-containing food additives in top-selling foods in grocery stores.
      • Sherman R.A.
      • Mehta O.
      Dietary phosphorus restriction in dialysis patients: potential impact of processed meat, poultry, and fish products as protein sources.
      • Moser M.
      • White K.
      • Henry B.
      • et al.
      Phosphorus content of popular beverages.
      In Table 1, we present data from a recent study
      • Moser M.
      • White K.
      • Henry B.
      • et al.
      Phosphorus content of popular beverages.
      examining phosphorus content in beverages containing phosphorus-based additives and compare measured values (Medallion Laboratories, Minneapolis, MN) with those reported by the Nutrient Data System for Research (NDSR) software version 2014. We also searched the USDA Standard Nutrient Reference Database,

      U.S. Department of Agriculture, Agricultural Research Service. USDA Food Composition Database, Release 28. Available at: https://ndb.nal.usda.gove/ndb/search. Accessed June 13, 2016.

      manufacturer websites,

      The Coca-Cola Company. What is in Coca Cola? A briefing on our ingredients. 2011. Available at: http://www.coca-colahellenic.gr/Download.aspx?ResourceID=122476. Accessed December 4, 2015.

      PepsiCo Inc. The Facts about Your Favorite Beverages: About Phosphorus. Available at: https://www.pepsicobeveragefacts.com/home/phosphorus. Accessed December 4, 2015.

      Sunny Delight Beverages Co. SunnyD FAQ. 2015. Available at: http://promo.sunnyd.com/about/index.html#. Accessed June 13, 2016.

      and 2 popular calorie tracking websites

      CalorieKing Wellness Solutions, Inc. CalorieKingTM Food Search. Available at: http://www.calorieking.com/. Accessed April 29, 2016.

      MyFitnessPal, Inc. MyFitnessPal Food Search. Available at: http://www.myfitnesspal.com/food/calorie-chart-nutrition-facts. Accessed April 29, 2016.

      to further investigate the extent of publically available data on phosphorus content for these beverages.
      Table 1Measured Phosphorus Content and Reference Values of Popular Beverages
      BeverageMeasured Phosphorus (mg per 8 fl oz)NDSR 2014 Reference Values for Phosphorus (mg per 8 fl oz)USDA Reference Values for Phosphorus (mg per 8 fl oz)Manufacturer Website Values (mg per 8 fl oz)Nutrition Panel Point Estimate or Range Estimate (min, max) (mg per 8 fl oz)
      Carbonated drinks
       Coke37.5 (0.2)252240.69
       Cherry Coke33.8 (0)25227.16
       Dr Pepper25.9 (0.2)2527
       Diet Dr Pepper27.1 (0.5)2121
       Pepsi31.2 (0.7)252235
       Diet Pepsi24.1 (0.3)212130
       AMP Energy30.9 (0.8)4039
      Exact match available in NDSR; for all other products closest substitute was selected.
      34
      Fruit-flavored drinks
       Crystal Light, Classic Orange
      Prepared from powder or concentrated liquid according to package instructions.
      100.5 (16.0)10951.5-154.5
       Crystal Light, Raspberry Ice
      Prepared from powder or concentrated liquid according to package instructions.
      2.4 (0.1)1040-15.5
       Crystal Light, Fruit Punch
      Prepared from powder or concentrated liquid according to package instructions.
      10.9 (0.5)10160-15.5
       Tang, Orange
      Prepared from powder or concentrated liquid according to package instructions.
      91.1 (5.0)3951102-208
       Kool-Aid, Tropical Punch
      Prepared from powder or concentrated liquid according to package instructions.
      2.7 (0.3)000-15.5
       Kool-Aid, Black Cherry
      Prepared from powder or concentrated liquid according to package instructions.
      2.4 (0.1)000-15.5
       Kool-Aid, Grape
      Prepared from powder or concentrated liquid according to package instructions.
      4.7 (0.6)000-15.5
       Hawaiian Punch, Fruit Juicy Red77.4 (0.3)7068.9-103.3
       Sunny-D, Tangy Original68.8 (0)41090
      Maximum phosphorus content per manufacturer's website.
       Sunny-D, Smooth69.0 (0.5)41090
      Maximum phosphorus content per manufacturer's website.
      Coffee drinks
       Starbucks Doubleshot Energy, Mocha
      Exact match unavailable in NDSR; closest substitute was selected.
      131.2 (0.2)13156110-164.1
       Starbucks Doubleshot Energy, Vanilla
      Exact match unavailable in NDSR; closest substitute was selected.
      130.2 (1.5)13140110-164.1
      Iced Teas
       Gold Peak Iced Tea, Sweet Tea
      Exact match unavailable in NDSR; closest substitute was selected.
      6.7 (0.2)20
       Gold Peak Iced Tea, Lemon
      Exact match unavailable in NDSR; closest substitute was selected.
      2.5 (0.2)23
      Exact match available in NDSR; for all other products closest substitute was selected.
       Lipton Brisk Iced Tea, Sweet Tea
      Exact match unavailable in NDSR; closest substitute was selected.
      105.2 (0.8)23126
       Lipton Brisk Iced Tea, Lemon
      Exact match unavailable in NDSR; closest substitute was selected.
      56.9 (0.5)26465.2
       Lipton Brisk Iced Tea, Raspberry
      Exact match unavailable in NDSR; closest substitute was selected.
      83.6 (3.8)26493.2
      Lemonade
       Crystal Light, Raspberry Lemonade
      Prepared from powder or concentrated liquid according to package instructions.
      8.0 (0.7)10180-15.5
       Country Time, Lemonade
      Exact match unavailable in NDSR; closest substitute was selected.
      15.8 (0.0)0180-18.4
       Country Time, Pink Lemonade
      Exact match unavailable in NDSR; closest substitute was selected.
      14.1 (0.2)0180-23
       Kool-Aid, Pink Lemonade
      Prepared from powder or concentrated liquid according to package instructions.
      7.3 (0.1)0180-15.5
      Vitamin Water, Power C Dragonfruit1.0 (0)000-11.1
      Vitamin Water, Revive Fruit Punch261.4 (1.7)00
      Exact match available in NDSR; for all other products closest substitute was selected.
      138.6-277.2
      Vitamin Water, Focus Kiwi Strawberry0.9 (0)000-11.1
      Vitamin Water, Essential Orange-Orange63.4 (0.7)0018.48-55.44
      Vitamin Water, Defense Raspberry Apple
      Exact match unavailable in NDSR; closest substitute was selected.
      1.5 (0.1)000-11.1
      Vitamin Water Zero, Squeezed Lemonade
      Exact match unavailable in NDSR; closest substitute was selected.
      86.2 (1.2)0020.6-72.9
      Vitamin Water Zero, Rise Orange
      Exact match unavailable in NDSR; closest substitute was selected.
      97.7 (1.7)0012.36-92.54
      Mio Fit, Arctic Grape
      Prepared from powder or concentrated liquid according to package instructions.
      Exact match unavailable in NDSR; closest substitute was selected.
      12.4 (2.1)8207.29-27.7
      Mio Fit, Berry Blast
      Prepared from powder or concentrated liquid according to package instructions.
      Exact match unavailable in NDSR; closest substitute was selected.
      14.4 (1.6)8207.29-27.7
      SoBe Lifewater, Blood Orange Mango
      Exact match unavailable in NDSR; closest substitute was selected.
      43.9 (0.5)0045.6
      Aquafina Flavor Splash, Mixed Berry
      Exact match unavailable in NDSR; closest substitute was selected.
      56.3 (0.7)62062.4
      Propel Zero, Berry54.9 (0.3)5959
      Exact match available in NDSR; for all other products closest substitute was selected.
      59.2
      Sports drinks
       Gatorade, Frost Glacier Freeze (powder)
      Prepared from powder or concentrated liquid according to package instructions.
      20.9 (3.2)02824.7
       Gatorade, Orange (powder)
      Prepared from powder or concentrated liquid according to package instructions.
      21.0 (4.4)028
      Exact match available in NDSR; for all other products closest substitute was selected.
      24.7
       Powerade Zero, Fruit Punch
      Exact match unavailable in NDSR; closest substitute was selected.
      18.0 (0.2)24019.01
       Powerade Zero, Orange
      Exact match unavailable in NDSR; closest substitute was selected.
      18.6 (0.1)24019.01
       Powerade, Fruit Punch18.7 (0.2)24219.01
       Powerade, Orange18.9 (0.1)24219.01
      NDSR, Nutrient Data System for Research.
      Means and standard deviations presented for each beverage, using 2 samples for each beverage except for Crystal Light, Classic Orange (5 samples).
      Exact match available in NDSR; for all other products closest substitute was selected.
      Prepared from powder or concentrated liquid according to package instructions.
      Maximum phosphorus content per manufacturer's website.
      § Exact match unavailable in NDSR; closest substitute was selected.
      Exact matches were found for 28 (61%) of the 46 beverages in NDSR. Phosphorus content was underestimated by NDSR for 78% of the beverages analyzed.
      • Moser M.
      • White K.
      • Henry B.
      • et al.
      Phosphorus content of popular beverages.
      The USDA Standard Nutrient Reference Database only had product-specific information for 11%
      • Sherman R.A.
      • Mehta O.
      Dietary phosphorus restriction in dialysis patients: potential impact of processed meat, poultry, and fish products as protein sources.
      of the beverages. Neither MyFitnessPal nor CalorieKing™ had any product-specific information on any of the products.

      CalorieKing Wellness Solutions, Inc. CalorieKingTM Food Search. Available at: http://www.calorieking.com/. Accessed April 29, 2016.

      MyFitnessPal, Inc. MyFitnessPal Food Search. Available at: http://www.myfitnesspal.com/food/calorie-chart-nutrition-facts. Accessed April 29, 2016.

      Manufacturer-reported data were available for 14 (30%) of the beverages and were very similar to measured values.

      The Coca-Cola Company. What is in Coca Cola? A briefing on our ingredients. 2011. Available at: http://www.coca-colahellenic.gr/Download.aspx?ResourceID=122476. Accessed December 4, 2015.

      PepsiCo Inc. The Facts about Your Favorite Beverages: About Phosphorus. Available at: https://www.pepsicobeveragefacts.com/home/phosphorus. Accessed December 4, 2015.

      Sunny Delight Beverages Co. SunnyD FAQ. 2015. Available at: http://promo.sunnyd.com/about/index.html#. Accessed June 13, 2016.

      Finally, for products lacking manufacturer reported data, we determined phosphorus content based on reported values of cation(s) (e.g., calcium) on the nutrition facts label, if provided (Table 1). Results for calculations that could be done were very close to what was measured and occasionally outperformed values from NDSR. Note that in some cases, only ranges were able to be calculated as manufacturers may write calcium phosphate on the label, which could include monocalcium, dicalcium, or tricalcium phosphate.
      Example calculation: Product X contains tricalcium phosphate and no other ingredients that contain a significant amount of phosphorus or calcium. Product nutrition label lists 10% Daily Value (DV) calcium in 1 serving.
      • Determine mass ratio for tricalcium phosphate.
        • Calcium = Ca = 40.08 amu; Phosphorus = P = 30.97 amu; Tricalcium phosphate = Ca3O8P2 (310.17 g/mol).
        • Calculate mass ratio of calcium in tricalcium phosphate = 40.08 g/mol × 3/310.17 g/mol = 38.76%.
        • Calculate mass ratio of phosphorus in tricalcium phosphate = 30.97 g/mol × 2/310.17 g/mol = 19.97%.
      • Calculate mass of tricalcium phosphate that contains 100 mg of calcium.
        • 100 mg calcium/38.76% = 258.00 mg of tricalcium phosphate.
      • Calculate mass of phosphorus in 258.00 mg of tricalcium phosphate
        • 258.00 mg tricalcium phosphate × 19.97% = 51.5 mg phosphorus in one serving
      In conclusion, consumer- and research-grade nutritional databases lack product-specific information and may not accurately capture the phosphorus content of foods and beverages containing phosphorus additives. We found that manufacturer websites that reported phosphorus values tended to be accurate and also propose an alternative method to calculate phosphorus content for products that contain phosphorus only from additives. Although our alternative method was able to approximate phosphorus content for some of the products analyzed, it has limited utility for clinical practice. Performing the calculations is time consuming, can only be performed in products without other sources of phosphorus, and even in those cases, may only provide a range if the manufacturer does not specify the numeric prefix for the ionic compound.
      Increasing awareness among food manufacturers about the importance of dietary phosphorus restriction in patients with kidney disease may help encourage self-reporting of phosphorus content and consequently improve the quality of dietary phosphorus content information available to both researchers and consumers.

      References

      1. Academy of Nutrition and Dietetics. Nutrition Care Manual®. March 30, 2016. Available at: http://www.nutritioncaremanual.org. Accessed June 13, 2016.

        • Calvo M.S.
        • Moshfegh A.J.
        • Tucker K.L.
        Assessing the health impact of phosphorus in the food supply: issues and considerations.
        Adv Nutr. 2014; 5: 104-113
        • Leon J.B.
        • Sullivan C.M.
        • Sehgal A.R.
        The prevalence of phosphorus-containing food additives in top-selling foods in grocery stores.
        J Ren Nutr. 2013; 23: 265-270.e2
        • U.S. Food and Drug Administration
        A Food Labeling Guide: Guidance for Industry.
        2013 (Available at:) (Accessed June 13, 2016)
        • Sherman R.A.
        • Mehta O.
        Dietary phosphorus restriction in dialysis patients: potential impact of processed meat, poultry, and fish products as protein sources.
        Am J Kidney Dis. 2009; 54: 18-23
        • Moser M.
        • White K.
        • Henry B.
        • et al.
        Phosphorus content of popular beverages.
        Am J Kidney Dis. 2015; 65: 969-971
      2. U.S. Department of Agriculture, Agricultural Research Service. USDA Food Composition Database, Release 28. Available at: https://ndb.nal.usda.gove/ndb/search. Accessed June 13, 2016.

      3. The Coca-Cola Company. What is in Coca Cola? A briefing on our ingredients. 2011. Available at: http://www.coca-colahellenic.gr/Download.aspx?ResourceID=122476. Accessed December 4, 2015.

      4. PepsiCo Inc. The Facts about Your Favorite Beverages: About Phosphorus. Available at: https://www.pepsicobeveragefacts.com/home/phosphorus. Accessed December 4, 2015.

      5. Sunny Delight Beverages Co. SunnyD FAQ. 2015. Available at: http://promo.sunnyd.com/about/index.html#. Accessed June 13, 2016.

      6. CalorieKing Wellness Solutions, Inc. CalorieKingTM Food Search. Available at: http://www.calorieking.com/. Accessed April 29, 2016.

      7. MyFitnessPal, Inc. MyFitnessPal Food Search. Available at: http://www.myfitnesspal.com/food/calorie-chart-nutrition-facts. Accessed April 29, 2016.