Dietary management of hyperphosphatemia in chronic kidney disease

c l i n i c a l q u e r i e s : n e p h r o l o g y 3 ( 2 0 1 4 ) 3 8 e4 5

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Review Article

Dietary management of hyperphosphatemia in chronic kidney disease Archana Sinha a, Narayan Prasad b,* a

Department of Dietetics, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India Department of Nephrology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

b

article info

abstract

Article history:

Dysregulation of phosphate homeostasis occurs in chronic kidney disease (CKD). Hyper-

Received 1 March 2014

phosphatemia is an ongoing challenge in treating CKD patients. Restriction of dietary

Accepted 21 March 2014

proteins remains one of the cornerstones of nutritional management of CKD patients foods

Available online 18 April 2014

from animal sources are rich in organic phosphorus. Foods sources including certain beverages like colas, enhanced meats, frozen meals, snack bars, processed or spreadable

Keywords:

cheeses, instant food products, and refrigerated bakery products are rich in inorganic

Hyperphosphatemia

phosphorus.

Dietary phosphorus

Phosphate additives added to foods further increases the phosphorus burden. It is

Food additives

estimated that the intestinal absorption of inorganic phosphorus is usually more than 90%

Phosphate binders

compared to only 40%e60% from that of the organic phosphorus. Phosphates from animal

Chronic kidney disease

food are more readily absorbed compared to that present in plant foods sources as majority of it is present in the form of phytate and hence not readily absorbed. Intensive nutritional counseling regarding phosphorus content of foods, their bioavailability with an emphasis on consumption of a mixed diet including foods from animal sources and plant sources high in phytate. While limiting or avoiding the intake from foods very high in phosphorus to protein ratio and foods rich in phosphorus additives but with an adequate protein content to avoid malnutrition, reinforcement on dietary compliance and judicious use of phosphorus binders are important for the better management of hyperphosphatemia in CKD. Methods like soaking foods in water and boiling them helps in reducing the dietary phosphorus content per gram of protein in foods. Copyright ª 2014, Reed Elsevier India Pvt. Ltd. All rights reserved.

1.

Introduction

Chronic Kidney Disease (CKD) is one of the important causes of morbidity and mortality worldwide. The associated mineral

and bone disorder (MBD) is one of the significant contributors to CKD.1 The progressive renal failure causes accumulation of many substances including phosphorus (P). In normal conditions, phosphorus is excreted by the kidney. A variety of

* Corresponding author. Tel.: þ91 5222495187, þ91 9415403140 (mobile); fax: þ91 5222668572. E-mail addresses: [email protected], [email protected] (N. Prasad). http://dx.doi.org/10.1016/j.cqn.2014.03.003 2211-9477/Copyright ª 2014, Reed Elsevier India Pvt. Ltd. All rights reserved.

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c l i n i c a l q u e r i e s : n e p h r o l o g y 3 ( 2 0 1 4 ) 3 8 e4 5

compensatory mechanisms keeps the serum P level within normal range until kidney functions starts deteriorating progressively to end stage renal disease (ESRD).2 This reduced P filtration and excretion with the progressive deterioration of kidneys leads to hyperphosphatemia.3 Serum phosphate above 5 mg/dl (1.6 mmol/l) is known as hyperphosphatemia.4 Optimum management of hyperphosphatemia is often a major challenge for renal care team involving nephrologists, nutritionist, nurses and for the patients themselves.5 The present article is aimed at reviewing the various aspects of dietary management of hyperphosphatemia in CKD patients Tables 1 and 2.

3.2.

The NKF KDOQI 2003 guidelines recommended aiming a normal phosphate level range of 2.7e4.6 mg/dl in patients with CKD stage 3e4 and a target of 3.5e5.5 mg/dl in CKD stage 5 and 5D.20As suggested by the Kidney Disease Improving Global Outcomes 2009 guidelines, the need is to regularize the levels of serum phosphates in stages 3e5 of CKD patients. It is also recommended that the levels of serum phosphorus should be within normal range for CKD patients in stage 5D; however these guidelines refrained from recommending specific targets21

3.3.

2.

Causes of hyperphosphatemia

Hyperphosphatemia is multifactorial in nature. (a) Neither hemodialysis nor peritoneal dialysis is able to effectively remove the dietary phosphorus6,7 (b) Non compliance with phosphate binder medications including pill burden and cost etc leading to insufficient phosphate removal8 (c) over concern regarding the consequences of dietary protein also limits the success in reducing dietary phosphorus intake9,10 (d) Lack of knowledge and awareness about the sources and content of phosphorus in various foodstuffs and non-compliance to dietary advice is also one of the important reasons for hyperphosphatemia.11e14 (e) Phosphate additives or preservatives used in processed foods contribute to phosphate burden.15

Dietary management

Mechanism of hyperphosphatemia

It is now known that the serum phosphate concentration is controlled by two newly discovered factors called fibroblast growth factor 23 (FGF 23) and klotho16,17 CKD patients are not able to excrete P properly. This diminish glomerular filtration of phosphorus is initially maintained by various compensatory mechanisms including decrease tubular reabsorption of P by PTH and FGF 23. This helps in maintenance of normal serum P.18 Afterward the serum phosphate increases with advanced stages of CKD.

3.1.

Treatment of hyperphosphatemia

Hyperphosphatemia remains ongoing challenge in clinical management of CKD and ESRD patients on either long-term peritoneal dialysis (PD) or Maintenance Hemodialysis (MHD). Therapeutic strategies targeting phosphorus control include restriction of dietary phosphorus, reducing intestinal absorption of phosphorus with appropriate phosphate binders, and removing phosphorus with dialysis.22 Dialysis patients on high protein diet are more prone to a higher dietary phosphorus load compared to the patients at early stages of CKD on medical management who are maintained on a low protein diet.23 A diet low in phosphorus together without/with inclusion of phosphate binders for stage 3 and 4 CKD even in patients with normal serum phosphorus levels patients may prevent the hyperphosphatemia.20,21,24

3.4.

3.

Target for serum phosphorus

Restriction of dietary proteins remains one of the cornerstones of nutritional management of CKD patients.25 Comprehensive management of hyperphosphatemia includes (5.26): (a) Judicious restriction of dietary phosphorus while maintaining adequate dietary protein intake (b) Decreasing intestinal absorption of phosphorus through use of appropriate phosphate binders (c) Removal of excess phosphate by intensifying dialysis therapy

Consequences of hyperphosphatemia

Hyperphosphatemia in long run may results in hyperparathyroidism, metabolic bone disease, calcifying uremic arteriolopathy, and cardiovascular calcification. Higher risk of death is caused by progressive increase in arterial calcification.19

Irrespective of the various options available, control of dietary phosphorus remains the forefront of management of hyperphosphatemia. Proper and adequate awareness and knowledge of various dietary sources of P is rudimentary and crucial in the dietary management of hyperphosphatemia in CKD patients.22 However, restriction of dietary phosphorus is

Table 1 e Table recommending intake of dietary phosphorus for stage 5 CKD patients. Guidelines NKF-K/DOQI 2003 ESPEN EBPG EDTNA/ERCA

Hemodialysis

Hemodialysis

Restricted to 800e1000 mg/day if serum phosphorus level >5.5 mg/dL 17 mg/kg IBW 800-1000 mg/day 1000e1400 mg/day

Restricted to 800e1000 mg/day if serum phosphorus level >5.5 mg/dL 17 mg kg IBW e 1000e1400 mg/day

Adopted from: NKF 2000 (DOQI)30: Toigo et al (2000) (ESPEN);31 EDTNA/ERCA 2002;32 Fouque et al (2007) (EPBG).33

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Table 2 e Phosphorus to protein ratio of various food items. Food (100 g) Whole wheat Whole wheat flour Refined wheat flour Rice Arhar dal Urd dal Mung dal Chana dal Chana dal whole Masoor dal Peas dry Peas dry Soyabean Rajmah Buffalo milk Cow milk Butter milk Whole milk powder Skim milk Skim milk powder Khoa (skim Buff) Khoa (whole Buff) Khoa (whole cow milk) Chicken Rohu Katla Mutton muscle Egg whole Egg yolka,48(1 large) Egg whitea,48(1 large) Coconut dry Coconut fresh Carrot Ground roasted Groundnuts Til Kala til Dates dry Kaju Walnut Almonds Makhana Oatmeal Singhara fresh Singhara dry

Phosphorus (P) (mg)

Protein (g)

P:protein ratio

306 355 121 143 304 385 405 331 312 293 298 139 690 410 130 90 30 730 90 1000 650 420 613 245 175 235 150 220 65 5 210 240 530 350 370 570 224 50 450 380 490 90 380 150 440

11.8 12.1 11 6.4 22.3 24 24.5 20.8 17.1 25.1 19.7 7.2 43.2 22.9 4.3 3.2 0.8 25.8 2.5 38 22.3 14.6 20 25.9 16.6 19.5 18.5 13.3 2.6 3.6 6.8 4.5 0.9 25.3 26.2 18.3 23.9 2.5 21.2 15.6 20.8 9.72 13.6 4.7 13.4

25.9 29.3 11 22.3 13.6 16.0 16.5 15.9 18.2 11.7 15.1 19.3 15.9 17.9 30.2 28.1 37.5 28.3 36 26.3 29.1 28.8 30.7 9.5 10.5 12.1 8.1 16.5 22.8 1.4 30.9 53.3 588.9 13.8 14.1 31.1 9.4 20 21.2 24.4 23.6 9.2 27.9 31.9 32.8

Based on nutritive value of Indian foods by C. Gopalan, B.V. Rama sastri and S.C. Balasubramanian. National Institute of Nutrition. ICMR. a USDA nutrient database.

often challenging and, not sufficient alone to control hyperphosphatemia. Patients with low GFR usually need phosphate binders in addition to dietary restrictions alone for managing hyperphosphatemia.27

4. Dietary phosphorus requirement\recommendations Restriction of dietary phosphorus is fundamental in management of CKD patients since many years.21Dietary advice

regarding the phosphate should be tailor made and individualized rather than generalized dietary instructions for all.28 Studies suggested that low dietary phosphorus is an important and appropriate aspect in the management of stage 1 and 2 of CKD as these stages may be associated with phosphorus retention, increased fibroblast growth factor 23 (FGF 23), and hyperphosphaturia.29 NKF-K/DOQI guidelines 2003 recommended that the dietary P should be limited to 800e1000 mg/ d adjusted for dietary protein requirements for the stage 3e4 CKD patients with serum P levels above 4.5 mg/dL and above 5.5 mg/dL in stage 5D CKD patients20,21 (Table 1). CKD patients in whom serum phosphate levels is not controlled properly by dietary restrictions alone, are prescribed appropriate phosphate binders in addition. As per K/DOQI guidelines, dietary P intake of 10e12 mg per gram of dietary protein or an average of 12e16 mg of P per gram of protein should be recommended per day.30

4.1.

Sources of phosphorus

A close relationship exists between the dietary protein and phosphorus.34 Dietary sources of proteins are also high in dietary phosphorus. Majority of scientific societies and dietary guidelines recommend reducing dietary protein intake at early stages of CKD to consequently decrease the dietary sources of phosphorus.35 Appropriate restrictions of the dietary phosphorus seem to be one of the mainstays of dietary management of hyperphosphatemia in CKD patients. For optimum dietary control of hyperphosphatemia in CKD patients, a complete knowledge regarding various dietary sources of phosphorus is a pre requisite.22 The main food sources of phosphorus are the protein food groups of meat, poultry, fish, eggs, and dairy products.36 For ensuring adequate protein intake to prevent malnutrition in CKD while restricting dietary phosphorus includes a thorough nutritional knowledge and awareness of dietary sources and bioavailability of phosphorus from various foods sources, calculating phosphorus to protein ratio and it helps to ensure adequate control of serum phosphate.37

4.2.

Organic phosphrus

Both animal and plant proteins contain organic phosphorus. Foods from animal sources like milk and milk products, meat, chicken, and fish are rich in organic P. These organic P is initially undergo hydrolysis in the intestinal tract and then absorbed into the blood stream.38 Around 40e60% of these organic P is absorbed.12

4.3.

Inorganic phosphrus

Foods sources including certain beverages like colas, enhanced meats, frozen meals, snack bars, processed or spreadable cheeses, instant food products, and refrigerated bakery products are rich in inorganic phosphorus.39,40 Infact P contributes to one of the main constituents in the preservatives and additive salts used in processed foods.10,41 These food additives or salts are used in food industries to extend self-life and to retain moisture, to enrich flavor and color of the processed foods.42,43

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Common soft drinks like cola having a high amount of phosphorus as well as phosphorus additives or preservatives added to foods contribute to additional phosphate burden in the diet.44 Unfortunately, we are lacking an accurate method to differentiate between the protein based organic and inorganic phosphorus present in the various food preservatives and additives.45,46 It should be noted that dietary phosphorus from non-protein sources varies widely and can be substantial. Bread, soft drinks, and salty snacks all can contribute phosphorus to the diet with little or no associated protein.47

4.4.

Bioavailibility

Phosphorus in foods is found in different forms. The varying bioavailability of dietary phosphorus from various food sources complexes the clinical and nutritional management of hyperphosphatemia.48 Apart from the quantity of phosphorus quality of dietary phosphorus is also very important for the management of hyperphosphatemia .The proper knowledge and awareness regarding the bioavailability of phosphorus from various food sources is crucial for assessing dietary phosphorus intake.49

4.4.1.

Bioavailability from organic phosphorus

The bioavailability of organic phosphorus present in proteins is usually low.35

4.4.2.

Bioavailability from inorganic phosphorus

Inorganic phosphorus present in food additives and preservatives are more readily disassociated and readily absorbed in the intestinal tract.47 It is estimated that the intestinal absorption of these inorganic phosphorus is usually more than 90% compared to only 40%e60% from that of the organic phosphorus present in foods.13,50 It is very difficult to assess the actual amount of additional phosphates present in processed foods as P is not being listed in the nutrition fact sheets by the manufacturers.41 Various other studies also reported that 100% of phosphorus from food additives (phosphoric acid and various polyphosphates) is absorbed compared to approximately 65% of naturallyoccurring dietary phosphorus.10,41,50 Dietary protein from animal origin contains varying proportions of phosphorus. Moreover, the phosphate additives used to enrich protein sources like meat and dairy products further increase their total phosphorus content.22 Thus these food sources of phosphorus can be a significant contributor to hyperphosphatemia and make it difficult to maintain a reduced intake level.10 A significant amount of dietary phosphorus comes from the processed and fast foods. The amount of phosphorus was almost two folds high in processed meat and poultry when compared to the amount found in those in natural products.51

4.4.3. foods

Bioavailability of P from animal versus plant based

Bioavailability of P from animal based foods is higher compared to that from foods sources of plant origin.22,48 Unlike plant foods, in which the majority of P (w75%) present in the form of phytate and hence not readily available for absorption, the phosphate from animal origin including meat is readily

41

and -easily hydrolyzed in GI tract and hence more readily absorbed.41 Phytate bound dietary protein sources like beans, peas, cereals, pulses and nuts etc are therefore have relatively low bioavailability of phosphorus.52,53 The comparatively low bioavailability of organic phosphorus from plant foods compared to animal foods is very important factor to be taken into consideration while planning a low phosphorus diet for controlling hyperphosphatemia in CKD patients. Hence a mixed diet is preferred to diet plan based on animal proteins alone.49 The low bioavailability of P from plant based foods compared to animal based foods may be advantageous in term that inspite of being apparently high in dietary phosphorus content, the actual intestinal phosphorus absorption per gram of protein seems to be relatively low for plant foods when compared to that from animal foods. The relatively lower bioavailability of dietary phosphorus from vegetarian food sources is an advantage that cannot be ignored in nutritional management of hyperphosphatemia.12 It may help in providing adequate protein while keeping the actual intake of dietary phosphorus relatively on lower side and hence helps in the better management of hyperphosphatemia. Moe et al in their study have reported that patients fed on vegetarian diet for one week resulted in decreased serum phosphorus levels and decreased FGF 23 level when compared to patients on meat based diet containing the same amount of dietary phosphorus.54 They observed that it is not only the total quantity of dietary phosphorus but also the quality and source of dietary phosphorus (whether from animal or from plant source) that significantly affects the phosphorus level of CKD patients.

5.

Hyperphosphatemia and risk of mortality

A number of studies have demonstrated a link between dysregulated phosphate homeostasis and increased mortality and morbidity. Guidelines and studies20,55 have documented that there are close relationship between the increased serum phosphorus values, a high calcium-phosphorus product and increased mortality. Various other epidemiologic studies56,57 have also reported the hyperphosphatemia as an independent risk factor for mortality in CKD patients. Kestenbaum et al58 have observed that a progressive increase in serum phosphorus level above 3.5 mg/dl was associated with an increased risk of mortality in stage 3 and 4 CKD patients. Several other studies59e61 have also supported the evidence that high serum phosphorus leads to increased morbidity and/or mortality in patients on dialysis and in patients at various stages of CKD. A higher dietary protein intake is linked with a high phosphorus intake and the later is associated with high cardiovascular mortality. In an observational prospective fiveyear study by Noori et al62 on 224 patients on maintenance hemodialysis, a high phosphorus was found to be a significant risk factor associated with mortality. They have observed that patients with a low dietary phosphate intake had a significant survival advantage. Patients with dietary intake above the 99th percentile died at a rate 2.37 folds higher than those with dietary phosphate intake below the first percentile. Even after adjusting for level of serum phosphates, dose and type of phosphate binders, dietary protein and calorie intake, the

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relations remains the same.62 Since hyperphosphatemia is associated with an increased risk of morbidity and/or mortality in CKD patients, restricting and controlling the dietary phosphorus may be very important in these patients.

6.

Estimating protein phosphorus ratio

Dietary protein intake is one of the important components of therapeutic management of CKD patients. Food sources high in dietary protein are also rich in organic phosphorus. A metric representing ratio of dietary phosphorus (mg) to protein in (g) for a given food item may be more suitable for CKD patients.22 Optimum dietary management of hyperphosphatemia includes the selection of foods rich in protein but low in dietary phosphorus. The K/DOQI guidelines recommend the use of phosphorus/protein food ratios for proper control of dietary phosphorus.20 Phosphorous content of foods varies from foods to foods. Tables are available depicting the protein and phosphorus content, phosphorus:protein ratio of different foodstuffs.37 These tables help in the better management of hyperphosphatemia. These composition tables also help in restricting the consumption of high phosphorus foods without compromising adequate consumption of proteins.29 A high amount of phosphoric acid is present in cheese and soft drinks in addition to high phosphorus:protein ratio.63 All these points should be kept in mind while managing hyperphosphatemia (Table 2).

7. Advantages and disadvantages of protein:phosphorus ratio The metric phosphorus advantages:20,22,48

protein

ratio

has

several

(1) This ratio does not depend on the food portion being served. (2) This ratio is a simultaneous representation of dietary phosphorus as well as protein, both of which play an important role in the dietary management of CKD patients. (3) The metric phosphorus to protein ratio is higher for the foods with high amount of phosphate additives but having similar amount of dietary protein eg cheese, soft drinks. (4) This ratio puts the emphasis on the foods very high in phosphorus especially in phosphate additives but low or absent in proteins eg soft drinks. This metric therefore helps in selecting the foods with desirable phosphorus to protein ratio by avoiding foods based solely upon phosphorus content appropriate for optimum management of CKD patients.35

8.

Disadvantage of phosphorus:protein ratio

The major limitation of the metric phosphorus to protein ratio as well as the absolute phosphorus level is that it does not

gives any information about the bioavailability or intestinal absorption rate of phosphorus present in different food items. Variations and inaccuracies in estimations of actual phosphorus content may make it difficult for patients and dieticians to accurately calculate the dietary phosphorus content.22 Oenning et al 64 reported that dietary phosphorus content is significantly underestimated by 15%e25% on comparison of 3 methods for estimating the dietary phosphorus content using both standard food tables and chemical analyses of 20 meals.64 However, this ratio has been a useful tool to be used for dietary management and education of CKD patients.22,48

9.

Importance of phosphorus education

Intensive nutritional counseling regarding phosphorus content of food,45 enforcement on dietary compliance, and imparting awareness about the consequences of hyperphosphatemia11 and judicious use of binders according to phosphorus content of meals is very important in hyperphosphatemia management. The patients as well as their caregivers should be educated regarding the advantages of dietary adherence and medication. They should be encouraged to take their phosphate binders with snacks and meals. They should be aware about the symptoms of hypocalcaemia and hyperphosphatemia, phosphorus content of common foods and must consult their doctors before using their complementary medications and therapy65 Achieving a normal serum phosphate level is usually a challenge. However, dietary education remains a very important tool in the management of hyperphosphatemic CKD patients. Some studies have evaluated the usefulness of educational counseling in the control of hyperphosphatemia in dialysis patients. As a whole, they suggest that focused education programs are effective in enhancing knowledge about phosphate in the dialysis population, and the impact may be most marked in patients with poor baseline knowledge.45,66,67 Phosphate education program (PEP) developed by Kuhlmann5 helped the patients self adjust their dose of phosphate binder depending on the P content of the meal they are going to eat just like adjusting insulin dose to carbohydrate intake. For the purpose one phosphorus unit (PU) is allotted per 100 mg of phosphorus and assigns PU values to food groups instead of food components, to enable patients to be able to “eye-estimate” the meal PU content.5 Study by Sullivan et al (n ¼ 279 with serum P level >5.5 mg/ dl) have reported that that there was a modest improvements in hyperphosphatemia after 3 months among patients (intervention group, n ¼ 145) through nutrition education regarding additives commonly found in foods. The decline in serum phosphorus levels was 0.6 mg/dL greater in intervention group compared to control group.42 Patients’ education including knowledge and awareness about the foods containing very high phosphorus compared to protein e.g. egg yolk and foods with high amount of phosphorus additives like soft drinks, phosphorus enriched meat, cheese and other dairy products are effective in reducing total

c l i n i c a l q u e r i e s : n e p h r o l o g y 3 ( 2 0 1 4 ) 3 8 e4 5

dietary phosphorus intake without reducing their required dietary protein intake.23 Pollock et al reported that nutritional knowledge and awareness was poor for P compared to other nutrients by using a 25-item CKD knowledge assessment tool for nutrition (CKDKAT-N).11Patients should also be educated about the oral intake of phosphate binders and their frequency as well as their timing.26

10. Measures for controlling hyperphosphatemia Cooking methods like boiling which helps in reducing phosphorus,45 use of selective vitamin D activators leading to decrease in intestinal absorption of phosphorus,68 diligent use of potent phosphorus binders with less pill burden,69e71 and phosphorus educational program72 are reported to be helpful in the clinical management of hyperphosphatemia Educating the patients about the use of the phosphorus to protein ratio is an important tool for the dietary management and education of CKD patients.22 A handout/leaflet/leave behind leaflet (LBL) containing a list of commonly consumed food items high in phosphorus, high in phosphorus to protein ratio, high in phosphorus containing additives, high in phosphoric acid, low in phosphorus which can be used as a substitute to those high in content should be provided to CKD patients in addition to routine diet counseling. Proper labeling of phosphate additives or preservatives present in foods may be represented through a “traffic light” system with green, yellow and red color on the food packages depicting low, medium and high content of phosphorus additives would be a good idea. It can help in the quantitative restriction of phosphate additives. These measures can be strictly implemented only through the proper involvement and support from the food industry, consumer protection organizations and medical authorities.73 Development of concept of low phosphorus content functional foods for CKD patients is also a good option to diversify the food choices among them. Kidney friendly shelf with low phosphorus functional and other foods nutritionally meant for CKD patients should find a place in food market or super market.74 Methods like soaking foods in water75 and boiling76 them helps in reducing the dietary phosphorus content per gram of protein in foods. Loss of water-soluble vitamins and palatability of food is a main problem with such methods.

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having a higher protein intake have improved survival outcome inspite of having a high dietary P consumption.77 Patients on unrestricted dietary protein intake were reported to have a better survival compared to the patients on a protein restricted diet.78 Foods high in dietary protein are also high in P content and a high P consumption is associated with increased cardiovascular mortality.62 Therefore dietary P restriction should always be cautiously done with adequate protein intake to decrease the risk of development of malnutrition in these patients.

11.1.

Monitoring

Dietary compliance in CKD may be assessed through subjective methods like diet diary and dietary recall and objective methods like monitoring of serum phosphates from time to time.79 Regular monitoring of serum phosphates is important and should be done once in a year in stage 3 CKD, once in three month in stage 4 CKD, once in a month in dialysis patients in once in fifteen days for phosphate binder dose adjustment irrespective of stage of CKD.80

12.

Summary and conclusions

Emphasis should be placed on a consumption of a mixed diet including foods from animal sources and plant sources high in phytate while limiting or avoiding the intake from foods very high in phosphorus to protein ratio and foods rich in phosphorus additives for the better management of hyperphosphatemia in CKD. Diet planning for these patients should include simultaneously the actual/absolute dietary phosphorus and phosphorus to protein ratio of food consumed by the patients.22 They should be prescribed a diet low in phosphorus especially low inorganic phosphorus and low phosphorus/protein ratio diet and a diet with an adequate protein content.35 Optimal control of hyperphosphatemia by through controlling phosphate intake from various sources can be achieved through More accurate reporting of phosphorus content of foods by manufacturers while simultaneously decreasing the risk of protein malnutrition.15,51

Conflicts of interest All authors have none to declare.

11. Phosphorus versus protein in ESRD patients on dialysis Restrictions of dietary phosphorus is routinely prescribed to optimally manage the increased serum phosphate levels in patients with CKD and are often associated with lower dietary protein intake, therefore lead to protein energy malnutrition resulting in inferior survival.77 Dietary phosphate restriction should not be done at the expense of protein malnutrition. ESRD patients on maintenance dialysis therapy should be prescribed a high protein diet. Patients on hemodialysis

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