Phosphorus Content in Beef and Chicken
Clin J Am Soc Nephrol. 2009 Aug; 4(8): 1370–1373.
Original Articles
Phosphorus and Potassium Content of Enhanced Meat and Poultry Products: Implications for Patients Who Receive Dialysis
Richard A. Sherman
Department of Medicine, Division of Nephrology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, New Brunswick, New Jersey
Ojas Mehta
Department of Medicine, Division of Nephrology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, New Brunswick, New Jersey
Received 2009 Apr 28; Accepted 2009 Jun 3.
- Supplementary Materials
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GUID: F9B1D7E7-186C-4860-B422-C1C9EE85F6B8
GUID: 580EA2E3-97E0-449A-AB58-BA4DD5EF2FC3
Abstract
Background and objectives: Uncooked meat and poultry products are commonly enhanced by food processors using phosphate salts. The addition of potassium and phosphorus to these foods has been recognized but not quantified.
Design, setting, participants, & measurements: We measured the phosphorus, potassium, and protein content of 36 uncooked meat and poultry products: Phosphorus using the Association of Analytical Communities (AOAC) official method 984.27, potassium using AOAC official method 985.01, and protein using AOAC official method 990.03.
Results: Products that reported the use of additives had an average phosphate-protein ratio 28% higher than additive free products; the content ranged up to almost 100% higher. Potassium content in foods with additives varied widely; additive free products all contained <387 mg/100 g, whereas five of the 25 products with additives contained at least 692 mg/100 g (maximum 930 mg/100 g). Most but not all foods with phosphate and potassium additives reported the additives (unquantified) on the labeling; eight of 25 enhanced products did not list the additives. The results cannot be applied to other products. The composition of the food additives used by food processors may change over time.
Conclusions: Uncooked meat and poultry products that are enhanced may contain additives that increase phosphorus and potassium content by as much as almost two- and three-fold, respectively; this modification may not be discernible from inspection of the food label.
The control of dietary phosphorus intake is the lynchpin in the successful control of hyperphosphatemia in dialysis patients (1). Other than limiting dairy products, efforts to reduce dietary phosphorus have been stymied by a belief that there is a close link between dietary protein and dietary phosphorus that can result in protein malnutrition if phosphorus control were to become too strict (2–4). The increasing recognition that phosphorus-containing food additives make up a significant portion of dietary phosphorus is changing this belief; clinicians are becoming more aware that efforts to limit dietary phosphorus can contribute substantially to serum phosphorus control without impairing protein intake (5–10).
One particular source of dietary phosphorus that is achieving growing recognition in the literature and national press is that resulting from the so-called "enhancement" of fresh meat and poultry products (11–13). This enhancement consists of the injection of a solution of water with sodium and potassium salts, particularly phosphates, as well as antioxidants and flavorings into the meat by a machine during processing (11). Marinated and cured meats are also considered enhanced when a similar process is used.
Despite the obvious problem for dialysis patients' ingesting such products, there is no requirement that their phosphorus or potassium content be included on the nutrition label (14,15), although this has been advocated (14,15). Furthermore, to our knowledge, there have been no published studies or other sources of data on potassium and phosphorus burdens imposed by fresh meat and poultry products that have been "enhanced." We therefore examined the potassium and phosphorus content in a variety of enhanced and regular meat and poultry products that are available in local retail stores.
Materials and Methods
Uncooked meat and poultry items were purchased at several local supermarkets. Products were arbitrarily chosen. A variety of products were sought, and an attempt was made to purchase both enhanced and regular versions of the same product. A portion of each item was then repackaged in sealable plastic bags and coded. All food labeling was saved. Bones were removed when present before repackaging. The coded samples were then transported to the laboratory for analysis (New Jersey Feed Laboratory, Trenton, NJ). Laboratory technicians were blinded to all food labeling information. All samples were ground before analysis. Potassium was measured using the Association of Analytical Communities (AOAC) official method 985.01. Phosphorus was measured using AOAC official method 984.27; both the potassium and phosphorus assays are inductively coupled plasma atomic spectroscopy procedures. Protein was measured using the AOAC official method 990.03, the Dumas nitrogen combustion method, with the Elementar Americas Rapid-N apparatus (Elementar Americas, Mt. Laurel, NJ). A Perkin-Elmer model Optima 2000 DV equipped with a model AS 90 plus Autosampler was used (Perkin-Elmer, Waltham, MA). Sample weights were obtained with a Sartorius model U 4800P balance (Sartorius Corp., Edgewood, NY). All instruments were calibrated according to manufacturers' specifications. Samples from the laboratory were routinely analyzed for accuracy by the American Association of Feed Control Officials and the American Oil Chemists Society.
For purposes of this investigation, we considered a meat or poultry product to be enhanced when this word was used on the package labeling (n = 8) or when this word was omitted but other terms suggesting the presence of food additives were noted on the label (n = 17), such as "cured," "contains solution," and "natural flavorings." We termed other meat and poultry products with no evidence indicating the presence of food additives as a "regular" (or additive-free) item (n = 11).
We report the potassium and phosphorus content as milligrams per 100 grams of product; however, for phosphorus, we also report this content as milligrams of phosphorus per gram of protein content; this is the measure generally used in the text. Because phosphorus content is closely tied to protein content, we believe that this is a more useful means of presenting these data; others agree (5,16).
Results
Enhanced meat and poultry products (EMPP) had on average a phosphorus-protein ratio that was 28.4% higher than that for regular products (Table 1). The average potassium content in EMPP was 8.7% higher than for regular products. This difference in mean values obscures a marked variability in potassium content in EMPP. Whereas the highest potassium content in a regular product was 387 mg/100 g, the five enhanced products with the most potassium contained at least 692 mg/100 g (maximum 930 mg/100 g). Although some differences in phosphorus and potassium content of the enhanced and regular products may be due to the different foods in the two groups, closer examination shows that food additives are likely to be the predominant factor. Figure 1 shows the data for equivalent products. For example, an enhanced pork chop had 81% more phosphorus than a visually identical regular pork chop.
Table 1.
Number | Item | Enhanced? | Phosphate(mg/100 g) | Protein(g/100 g) | Phosphorus-Protein Ratio(mg/g) | Potassium(mg/100 g) |
---|---|---|---|---|---|---|
1 | Bone-In Loin Center Cut Pork Chops | Y | 340 | 19.6 | 17.35 | 584 |
2 | Kirkwood Ice Glazed Boneless, Skinless Chicken Breasts with Rib Meat | Y | 190 | 21.7 | 8.76 | 315 |
3 | Kirkwood Ice Glazed Chicken Drumsticks | Y | 170 | 18 | 9.44 | 238 |
4 | Kirkwood Ice Glazed Chicken Wings | Y | 120 | 17.5 | 6.86 | 170 |
5 | Pork Boneless Loin Country Style Pork Ribs | Y | 230 | 20.1 | 11.44 | 671 |
6 | USDA Select Beef Boneless Loin Strip Steak | Y | 260 | 19.4 | 13.40 | 930 |
7 | USDA Select Beef Boneless Chuck Roast | Y | 200 | 17.9 | 11.17 | 561 |
8 | Granger Beef Filet of Sirloin | Y | 250 | 19.6 | 12.76 | 331 |
9 | Appleton Center Slice Hardwood Smoked Ham | Y | 210 | 18.1 | 11.60 | 255 |
10 | Granger Beef USDA Choice Beef T-Bone Steaks | Y | 240 | 19.3 | 12.44 | 261 |
11 | Boar's Head Naturally Smoked Sliced Bacon | Y | 100 | 10.4 | 9.62 | 185 |
12 | John Morrell Hardwood Smoked Bacon | Y | 120 | 9.4 | 12.77 | 164 |
13 | Nature's Promise Uncured Hickory Smoked Bacon | N | 110 | 11.8 | 9.32 | 246 |
14 | Oscar Meyer Naturally Hardwood Smoked Bacon | Y | 150 | 11.2 | 13.39 | 205 |
15 | Hormel Black Label Bacon Original | Y | 120 | 12.2 | 9.84 | 233 |
16 | Stop & Shop Fresh White Gem Chicken All Natural Drumsticks | N | 170 | 19.3 | 8.81 | 256 |
17 | Stop & Shop Tender & Flavorful Pork Loin Chops | N | 210 | 21.9 | 9.59 | 366 |
18 | Stop & Shop Tender & Flavorful Pork Loin Ribs | N | 210 | 21.8 | 9.63 | 387 |
19 | Stop & Shop Fresh White Gem Chicken All Natural Boneless Skinless Breasts with Rib Meat | N | 220 | 25.6 | 8.59 | 364 |
20 | Stop & Shop Grilling & Boiling Boneless Strip Steaks | N | 170 | 21.1 | 8.06 | 311 |
21 | Stop & Shop Grilling & Boiling Beef Loin Top Sirloin Boneless Steaks | N | 180 | 21.2 | 8.49 | 328 |
22 | Stop & Shop Tender & Flavorful Pork Hocks | N | 160 | 20.3 | 7.88 | 268 |
23 | Shadybrook Farms All Natural Turkey Breast Cutlets | Y | 220 | 25.5 | 8.63 | 337 |
24 | Stop & Shop Chicken Breast Boneless Cutlets | N | 220 | 26.7 | 8.24 | 367 |
25 | Perdue Oven Stuffer Fresh All Natural Roaster Drumsticks | N | 170 | 19.4 | 8.76 | 273 |
26 | Perdue Fresh All Natural Chicken Wings | N | 140 | 18.2 | 7.69 | 217 |
27 | Freirich Flavor Porkette Pork Shoulder Butt | Y | 210 | 17.4 | 12.07 | 232 |
28 | Freirich Flavor Corned Beef Brisket | Y | 130 | 17.6 | 7.39 | 222 |
29 | Smithfield Hardwood Smoked Ham | Y | 240 | 17.5 | 13.71 | 255 |
30 | Hillshire Farm Polska Kielbasa (Made with Pork, Turkey, Beef) | Y | 170 | 11.3 | 15.04 | 187 |
31 | Hillshire Farm Beef Polska Kielbasa | Y | 150 | 12.4 | 12.10 | 197 |
32 | Nebraska Meat Smoked Turkey Drums | Y | 200 | 22.4 | 8.93 | 249 |
33 | Nebraska Meat Smoked Pork Hocks | Y | 160 | 26.8 | 5.97 | 238 |
34 | Butterball Premium Young Turkey | Y | 260 | 24.1 | 10.79 | 310 |
35 | Kirkwood Turkey Breast Roast | Y | 230 | 22.5 | 10.22 | 317 |
36 | Tender Choice Boneless Thin-Cut Pork Chops | Y | 240 | 20.7 | 11.59 | 714 |
Whether an EMPP listed specific additives on the ingredient label varied; 16 of 25 such products did so. When these additives were specifically named, this information offered useful guidance as to the potassium and phosphorus content of the product. The 15 EMPP with specific labeling and no potassium additives had only 235 mg/100 g potassium, whereas the two products that specifically excluded phosphate salts had a phosphorus-protein ratio of only 8.6 mg/g protein. EMPP with no specifics on the label had a wide range for both potassium (170 to 930 mg/100 g) and phosphorus (6.86 to 17.35 mg/g protein) content. The presence of phosphorus on the ingredient label of an EMPP (n = 14) indicated a higher average level of phosphorus (mean 11.6 mg/g protein), but the range extended from 6 to 15 mg/g protein.
Discussion
The use of phosphorus-containing food additives became widespread in the United States after a 1982 ruling by the Food Safety and Inspection Service of the US Department of Agriculture allowed expanded use of these products. The term "enhanced" is sometimes limited to meat and poultry that is altered primarily for reasons other than flavor and that has other than "natural" ingredients. These enhanced products are required to report the specific additives used, although they are not quantified; however, a chicken breast marinated in seasoning or in a "natural" broth solution might contain added phosphorus but does not fall under the narrow definition of an enhanced meat product. The more broadly defined EMPP generally do not detail the chemical composition of the additives used.
Although much attention has been paid to the added sodium and phosphorus in processed foods, none has been paid to the added potassium. Our data indicate that more attention is warranted. In some EMPP, little potassium seems to have been added (e.g., sirloin steak: product 8 [enhanced] versus product 21 [regular]), whereas in others, the amount of added potassium is striking. The enhanced boneless loin strip steak (product 6) had 930 mg of potassium per 100 g, a level three-fold higher than a similar regular product (product 20). Thus, a 200-g portion would contain almost 2 g of potassium, most of a dialysis patient's daily restricted intake. A dialysis patient who eats this product would be at increased risk for the development of hyperkalemia; its origin would very likely be unrecognized.
The discordance between potassium and phosphorus content in these products is not surprising given the approval (by the US Department of Agriculture) of 11 different phosphate salts for use in meat and poultry products: six are sodium salts, and five are potassium salts. These salts differ in their properties and serve different purposes in food processing.
The impact of addition of phosphorus to EMPP is likely to be clinically significant, especially so in view of the probability that phosphorus in food additives is much better absorbed than phosphorus that is contained in unprocessed foods (1,12). Increasing the clinical importance of this added phosphorus further is its disproportionate effect on phosphorus binder requirements. Binders are required to remove only phosphorus that is not eliminated by dialysis; however, dialytic phosphorus removal is relatively fixed for a given plasma phosphorus concentration for standard thrice-weekly hemodialysis (although not with more frequent dialysis regimens) (17). Any additional dietary phosphorus will thus need to be removed by binders. For example, with a dietary phosphorus of 8400 mg/wk (1200 mg/d), binders and dialysis are needed to eliminate 5040 mg/wk (assuming that 60% of phosphorus is potentially absorbed). If dialysis removes 3000 mg, then binders must remove 2040 mg. A rise in dietary phosphorus from 1200 to 1500 mg/d, a 25% increase, would increase phosphorus binding requirements by 62%. The increase in binder requirement would probably be even greater because the calculation ignores any facilitated absorption of phosphorus in the form of additives.
We did not examine the effect of cooking on phosphorus or potassium content. Cooking is likely to alter theses results in an inconsistent way depending on the specific cooking method. Retail cost was also not formally compared for the products; however, producer costs for EMPP are clearly lower, a difference likely to be reflected in retail cost.
Avoiding phosphorus in uncooked meat and poultry products requires close attention to food labels. Although avoiding food that indicates added phosphorus salts will reduce dietary phosphorus burden (6), additional restrictions are needed because not all EMPP list the salts used in processing. It is also necessary to avoid enhanced foods that may refer only to "added solution" or broth to minimize the risk for excessive unrecognized dietary phosphorus. Similar restrictions are needed to avoid potassium excess. The burden imposed on those who seek to limit dietary phosphorus and potassium could be ameliorated by more complete food labeling by manufacturers.
Supplementary Material
Acknowledgments
This study was supported by unrestricted educational grants from Dialysis Clinics, Inc., and Genzyme, Inc.
Footnotes
Published online ahead of print. Publication date available at www.cjasn.org.
See related editorial, "Phosphorus Additives in Food and their Effect in Dialysis Patients," on pages 1290–1292.
References
1. Uribarri J: Phosphorus homeostasis in chronic kidney disease patients with special emphasis on dietary phosphorus intake. Semin Dial 20: 295–301, 2007 [PubMed] [Google Scholar]
2. Shinaberger CA, Greenland S, Kopple JD, Van Wyck D, Mehrotra R, Kovesdy CP, Kalantar-Zadeh K: Is controlling phosphorus by decreasing dietary protein intake beneficial or harmful in persons with chronic kidney disease? Am J Clin Nutr 88: 1511–1518, 2008 [PMC free article] [PubMed] [Google Scholar]
3. Uribarri J: The obsession with high dietary protein intake in ESRD patients on dialysis: Is it justified? Nephron 86: 105–108, 2000 [PubMed] [Google Scholar]
4. Sherman RA: Dietary phosphate restriction and protein intake in dialysis patients: A misdirected focus. Semin Dial 20: 16–18, 2007 [PubMed] [Google Scholar]
5. Cupisti A, D'Alessandro C, Baldi R, Barsotti G: Dietary habits and counseling focused on phosphate intake in hemodialysis patients with hyperphosphatemia. J Ren Nutr 14: 220–225, 2004 [PubMed] [Google Scholar]
6. Sullivan C, Sayre SS, Leon JB, Machekano R, Love TE, Porter D, Marbury M, Sehgal AR: Effect of food additives on hyperphosphatemia among patients with end-stage renal disease. JAMA 301: 629–635, 2009 [PubMed] [Google Scholar]
7. Sullivan CM, Leon JB, Sehgal AR: Phosphorus-containing food additives and the accuracy of nutrient databases: Implications for renal patients. J Ren Nutr 17: 350–354, 2007 [PMC free article] [PubMed] [Google Scholar]
8. Kestenbaum B: Phosphate metabolism in the setting of chronic kidney disease: Significance and recommendations for treatment. Semin Dial 20: 286–294, 2007 [PubMed] [Google Scholar]
9. Sherman RA, Mehta O: Dietary phosphorus restriction in dialysis patients: Potential impact of processed meat, poultry, and fish products as protein sources. Am J Kidney Dis 54: 18–23, 2009 [PubMed] [Google Scholar]
10. Sarathy S, Sullivan C, Leon JB, Sehgal AR: Fast food, phosphorus-containing additives, and the renal diet. J Ren Nutr 18: 466–470, 2008 [PubMed] [Google Scholar]
11. Murphy-Gutekunst L, Uribarri J: Hidden phosphorus-enhanced meats: Part 3. J Renal Nutr 15: E1–E4, 2005 [Google Scholar]
12. Uribarri J, Calvo MS: Hidden sources of phosphorus in the typical American diet. Does it matter in nephrology? Semin Dial 16: 186–188, 2003 [PubMed] [Google Scholar]
13. Burros M: The customer wants a juicy steak? Just add water. New York Times, August9, 2006 [Google Scholar]
14. Sehgal AR, Sullivan C, Leon JB, Bialostosky K: Public health approach to addressing hyperphosphatemia among dialysis patients. J Ren Nutr 18: 256–261, 2008 [PMC free article] [PubMed] [Google Scholar]
15. Karalis M: Food and Drug Administration petition on food labeling: An update from the American Diabetic Association and National Kidney Foundation. J Ren Nutr 17: 423–424, 2007 [PubMed] [Google Scholar]
16. National Kidney Foundation: K/DOQI clinical practice guidelines for bone metabolism and disease in chronic kidney disease. Am J Kidney Dis 42[Suppl 3]: S1–S202, 2003 [PubMed] [Google Scholar]
17. Kooienga L: Phosphorus balance with daily dialysis. Semin Dial 20: 342–345, 2007 [PubMed] [Google Scholar]
Articles from Clinical Journal of the American Society of Nephrology : CJASN are provided here courtesy of American Society of Nephrology
Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2723964/
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