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onflicting Dietary Advice for Adhering toow-Sodium and Low-Phosphorus Diets

onathan B. Jaffery, MD,* and Virginia L. Hood, MBBS, MPH†

Objective: To elucidate conflicts that patients face when advised to limit multiple nutrients in their diet.Design: We analyzed the phosphorus content of low-sodium foods compared with their regular-sodium content

ounterparts, and the sodium content of low-phosphorus foods compared with foods containing higher levels ofhosphorus. Low-sodium and low-phosphorus foods were identified with the use of recommendations fromational Kidney Foundation patient information Web sites. Content of sodium and phosphorus was quantified withse of the US Department of Agriculture (USDA) Nutrient Database.Setting: Review and analysis of publicly available patient information Web sites and nutrient databases.Main Outcome Measure: Phosphorus content of low- versus regular-sodium–containing foods, and sodium

ontent of low- versus high-phosphorus–containing foods.Results: Of 47 low-sodium foods, 32 had identical phosphorus content—8 higher and 7 lower—compared with

egular-sodium alternatives. Of 9 foods recommended as low-phosphorus alternatives to high-phosphorushoices, 4 had higher sodium content and 5 had lower, with considerable variability. However, choosing servingsf 4 low-sodium alternatives could increase ingestion of phosphorus by up to 16% of recommended intake, andhoosing servings of 4 low-phosphorus alternatives could increase ingestion of sodium by more than 20% ofecommended intake.

Conclusion: Adhering to a complex renal diet is extremely difficult for patients with chronic kidney disease.alancing sodium and phosphorus restrictions is particularly challenging, especially as food choices low in oneutrient may not be low in the other. To help patients follow these diets, alternative methods of achieving dietaryestrictions of multiple, often conflicting, components may be needed.

2006 by the National Kidney Foundation, Inc.

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atients with chronic kidney disease (CKD) areoften advised to adjust their diet in an effort to

low disease progression and prevent the develop-ent of complications. This advice typically in-

ludes limiting the intake of various minerals, in-luding sodium and phosphorus. Limiting sodium iselpful for control of blood pressure1,2; limiting

*Assistant Professor of Medicine, University of Wisconsin, Mad-son, Wisconsin and

†Professor of Medicine, University of Vermont, Burlington,ermont, USA.Dr. Jaffery is supported by NIH 5K12RR017614-03.Address reprint requests to Jonathan B. Jaffery, MD, Assistant

rofessor of Medicine, University of Wisconsin Medical School, 3034ish Hatchery Road, Suite B, Madison, WI 53713. E-mail: jbj@edicine.wisc.edu© 2006 by the National Kidney Foundation, Inc.1051-2276/06/1604-0006$32.00/0

vdoi:10.1053/j.jrn.2006.07.008

Journal32

hosphorus can help prevent the bone disease ofKD3 and may slow progression of kidney disease

nd reduce cardiovascular complications.4-9 Unfor-unately, compliance with dietary instructions cane burdensome, confusing, and overwhelming foratients, particularly when they are faced with ad-ice to limit multiple types of food.Sodium content is listed on package labeling;

owever, such labeling does not typically includehe phosphorus content of foods. Because low-odium foods do not necessarily have decreasedhosphorus content, patients who manage to ad-ere to the more readily identifiable low-sodiumiet may be likely to continue to ingest foods thatontain high levels of phosphorus. Similarly, aell-followed low-phosphorus diet may result inormal or even high sodium intake. This studyims to evaluate the phosphorus content of a

ariety of low-sodium foods and low-sodium

of Renal Nutrition, Vol 16, No 4 (October), 2006: pp 332-336

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PATIENT EDUCATION 333

ersions of foods, as well as the sodium content ofow-phosphorus foods.

MethodsUsing the US Department of Agriculture

USDA) Nutrient Data Laboratory’s Nationalutrient Database,10 we analyzed the phosphorus

ontent of foods recommended to patients withKD as low in sodium in the “Sodium and YourKD Diet” of the National Kidney Foundation

NKF),11 under the patient information sectionf the NKF Web site. We then analyzed thehosphorus content of the regular-sodium ver-ions of these foods. Because the USDA Nutrientatabase contains many different types of certain

oods, we chose the version closest in waterontent to the low-sodium version for non–low-odium soups and gravies. We eliminated thoseoods for which no comparable non–low-sodiumersions were available in the database.We then analyzed the sodium content of low-

hosphorus foods recommended on the NKFPhosphorus and Your CKD Diet” patient infor-ation page of the NKF Web site12 and compared

his with the sodium content of high-phosphorusoods on the same site. We eliminated the com-arison between milk and nondairy creamer, asell as the comparison between custard or pud-ing made with milk versus nondairy creamer,ecause the latter is not available in the USDAutrient Database.The NKF Web sites were chosen for several

easons. As a large, kidney disease–specific orga-ization, the NKF is well known to many indi-iduals with kidney disease and is a leader inatient education for those with CKD. Further-ore, patient education information on diet andutrition in CKD is available free of charge onhe NKF Web sites, which provided very specificood recommendations suitable for our analysis.

e chose the USDA database because it is theasis for all diet analysis programs in the Unitedtates, and it is readily available.

Resultshosphorus Content in Low-Sodiumersus Non–Low-Sodium FoodsTotal phosphorus content for a typical serving

ize of all foods listed in the NKF “Sodium and

our CKD Diet” patient information section of the t

KF Web site as advisable to avoid because of highodium content11 was 3,546 mg—slightly lowerhan the total phosphorus content in the low-so-ium versions of all these foods of 3,757 mg (Table). Of 47 low-sodium foods, 32 had identicalhosphorus content to the comparable high-odium foods, 8 had higher phosphorus con-ent, and 7 had lower phosphorus content;ifferences in phosphorus content were gener-lly small (average difference, 1.3 mg; standardeviation [SD], 16.4; range of difference, 57 to0 mg).

odium Content in Low-Phosphorusersus High-Phosphorus FoodsTotal sodium content for a typical serving size

f all foods listed in the NKF “Phosphorus andour CKD Diet” patient information section of

he NKF Web site as advisable to avoid becausef high phosphorus content12 was 1,824 mg,lightly higher than the total sodium content forhe recommended low-phosphorus choices of,815 mg (Table 2). Of 9 low-phosphorus foods,had higher sodium content than the comparableigh-phosphorus choices, and 5 had lower so-ium content (average difference, 1.0 mg; SD,86.5; range of difference, 370 to 410 mg).

DiscussionThe renal diet is extraordinarily complex and is

rescribed to a population that almost universallyxperiences multiple medical problems. Identify-ng foods that fulfill all the desired criteria remainshuge challenge, and following a low-phospho-

us diet may be particularly challenging, givenhat phosphorus content is not typically readilyvailable on nutrition labeling. Furthermore, asurphy-Gutekunst reports in a recent series,13,14

any foods are unsuspecting sources of highhosphorus, and the use of food additives withigh levels of sodium and phosphorus has greatlyncreased the typical daily intake of these nutri-nts in the American diet over the past 15 years.15

Our analysis reveals yet another aspect of thehallenge involved in trying to adhere to the renaliet—the conflicting messages delivered, as limitingne mineral often conspires against the ability to

imit another. As even the most motivated patientseek concrete information about how to avoid food

hat contains high levels of different minerals, easily

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JAFFERY AND HOOD334

vailable information is often contradictory. Forxample, a person who chooses low-sodium serv-ngs of corn chips, mozzarella cheese, bakedeans, and chicken vegetable soup, while de-

able 1. Phosphorus Content of High-Sodium Vers

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Sauce, barbecue Cup 50Sauce, spaghetti Cup 90Sauce, tomato chili Cup 142Soy sauce Tsp 6Blue cheese dressing Tbsp 11French dressing Tbsp 3Italian dressing Tbsp 1Mavonnaise, soybean oil Tbsp 4Popcorn, oil-popped 1 oz 71Pretzels, plain 1 oz 32Tortilla chips, white corn 1 oz 56Corn chips 1 oz 52Potato chips, plain 1 oz 47Cheese, mozzarella 1 oz 147Cheese, parmesan Tbsp 40Cheese, Swiss 1 oz 169Applesauce, canned Cup 18Salmon, pink, canned 3 oz 280Tuna, light, canned in water 3 oz 139Tuna, light, canned in oil 3 oz 264Pumpkin, canned Cup 86Summer squash, cooked Cup 70Tomato juice, canned 6 oz 33Tomato paste, canned 6 oz 141Tomato puree, canned Cup 100Asparagus, canned Cup 46Baked beans, canned Cup 263Green beans, canned Cup 26Snap peas, canned Cup 13Beets, canned Cup 39Carrots, canned Cup 35Whole kernel corn, canned Cup 65Lima beans, canned ½ cup 88Peas and carrots, canned Cup 117Green peas, canned Cup 57Potatoes, canned Cup 50Spinach, canned Cup 75Tomatoes, canned Cup 46Turnip greens, canned Cup 30Vegetables, mixed, canned Cup 67Soup, bouillon cubes, dry Cube 6Chicken broth, canned Cup 72Chicken noodle soup Can 70Cream of mushroom soup Can 119Pea soup Cup 125Tomato soup Cup 34Chicken vegetable soup Cup 106

Values are shown in milligrams (mg).*Negative values in the final column reflect lower phosp

reasing sodium intake by 3,008 mg, would in- c

rease phosphorus intake by 128 mg, representing2.8% to 16% of the total phosphorus intakeecommendation of 800 to 1,000 mg for peopleith stages 3 and 4 CKD. Similarly, a person who

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76 75 746 024 46 307 042 30 399 047 68 243 �138 7 743 �172 72 763 028 88 2690 �1219 119 2141 025 125 918 049 34 695 084 81 1897 �25

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PATIENT EDUCATION 335

rits versus oatmeal, popcorn versus peanuts,ixed vegetables versus lima beans, ginger ale

ersus cola), while decreasing phosphorus intakey 363 mg, would increase sodium intake by 492g, representing more than 20% of the sodium

ntake recommendation of 2,400 mg. Given thatodium content is ubiquitous on nutritional la-eling and has been more readily acknowledgeds a public health problem, we believe it is likelyhat patients with CKD remain particularly chal-enged in their ability to decrease phosphorusntake, despite counseling provided in the coursef their care. Ultimately, alternative approachesay be needed, such as improvements in con-

umer health information that would lead to easynd rapid identification of food items appropriateo highly tailored diets (eg, labeling of phos-horus content on nutrition labels, implement-ng a rating system for food products based onheir desirability for a CKD diet), productionf foods that are modified to remove multiplenwanted minerals while maintaining taste (eg,enetically modified animals, production-levelhosphorus removal of milk), use of alternativeood additives with lower sodium and phos-horus content, and production of affordablend palatable prepared foods that have beenailored to renal diets at various stages of CKD.

References1. Conlin PR, Chow D, Miller ER, 3rd, et al: The effect of

ietary patterns on blood pressure control in hypertensive pa-ients: Results from the Dietary Approaches to Stop Hyperten-ion (DASH) trial. Am J Hypertens 13:949-955, 2000

2. Johnson RJ, Herrera-Acosta J, Schreiner GF, et al: Subtlecquired renal injury as a mechanism of salt-sensitive hyperten-ion. N Engl J Med 346:913-923, 2002

3. K/DOQI clinical practice guidelines for bone metabolismnd disease in chronic kidney disease. Am J Kidney Dis 42:S1-201, 20034. Haut LL, Alfrey AC, Guggenheim S, et al: Renal toxicity

f phosphate in rats. Kidney Int 17:722-731, 19805. Block GA, Hulbert-Shearon TE, Levin NW, et al: Asso-

iation of serum phosphorus and calcium x phosphate productith mortality risk in chronic hemodialysis patients: A national

tudy. Am J Kidney Dis 31:607-617, 19986. Nishizawa Y, Jono S, Ishimura E, et al: Hyperphos-

hatemia and vascular calcification in end-stage renal disease.Ren Nutr 15:178-182, 20057. Raggi P, Boulay A, Chasan-Taber S, et al: Cardiac calci-

cation in adult hemodialysis patients: A link between end-stageenal disease and cardiovascular disease? J Am Coll Cardiol9:695-701, 20028. Hruska KA, Mathew S, Davies MR, et al: Connections

between vascular calcification and progression of chronic kidneyTa 8 1 ½ 1 ½ 1 1 2 ½ V *

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JAFFERY AND HOOD336

isease: Therapeutic alternatives. Kidney Int Suppl S142-S151,0059. Koizumi T, Murakami K, Nakayama H, et al: Role of

ietary phosphorus in the progression of renal failure. Biochemiophys Res Commun 295:917-921, 200210. US Department of Agriculture. Nutrient Data Laboratoryational Nutrient Database. Available at: http://www.nal.usda.

ov/fnic/foodcomp/search/11. National Kidney Foundation Web site. Sodium and your CKD

iet. Available at: http://www.kidney.org/atoz/atozItem.cfm?id�175. m

12. National Kidney Foundation Web site. Phosphorus andour CKD diet. Available at: http://www.kidney.org/atoz/tozItem.cfm?id�101

13. Murphy-Gutekunst L: Hidden phosphorus in populareverages: Part 1. J Ren Nutr 15:e1-e6, 200514. Murphy-Gutekunst L, Barnes K: Hidden phosphorus at

reakfast: Part 2. J Ren Nutr 15:e1-e6, 200515. Karalis M, Murphy-Gutekunst L: Patient education. En-

anced foods: Hidden phosphorus and sodium in foods com-

only eaten. J Ren Nutr 16:79-81, 2006