Mitch_edit.qxp 8/2/08 09:56 Page 43
Dietary Protein Restriction in the Management of Chronic Kidney Disease
Table 2: Specific Dietary Requirements for Patients with Chronic Kidney Disease
3
Patients Minimum Protein Requirements Notes
Normal adults 0.6g of protein/kg per day 30–35kcal/kg per day needed to utilise dietary protein efficiently
Those with uncomplicated Adjustments for specific problems (diabetes, hyperphosphataemia)
chronic kidney disease (CKD)
CKD patients with muscle mass loss 0.8g of protein/kg per day Ensure 30–35kcal/kg per day
CKD patients with proteinuria <0.8g of protein/kg per day plus 1g protein per gram of proteinuria This is the maximum needed
that lowering protein intake in patients with CKD reduced the dietary habits is difficult, but compliance with any therapeutic
occurrence of renal death by 31% compared with patients receiving intervention can be difficult. A skilled dietician can formulate a
higher-protein diets.
46
The benefits of protein-restricted diets on balanced diet that is acceptable to most patients, and even in
independent predictors of kidney failure are highly suggestive of a a gastronomic country such as France a report by Aparicio et al.
beneficial effect. For example, hypertension and proteinuria are two showed that nearly two-thirds of French patients with CKD complied
major factors associated with the progressive loss of kidney function.
47
with low-protein diets.
53
Kanazawa and colleagues reported that there
was no correlation between dietary protein restriction and the health-
related quality of life responses of patients. They also noted that an
appropriate social support structure is associated with better patient
Although diet implementation can
compliance.
54
Although diet implementation can increase therapy
increase therapy costs, the costs
costs, the costs associated with dietary counselling are lower than
the costs of dialysis therapy.
55
associated with dietary counselling are
lower than the costs of dialysis therapy.
Low-protein Diets and ‘Malnutrition’
Many nephrologists and other physicians are reluctant to implement
low-protein diets because they are concerned that dietary protein
restriction is unsafe and/or will lead to diminished muscle mass and
Protein restriction has been shown to decrease the degree of ‘malnutrition’. In addressing this concern, investigators have shown
proteinuria
19,48
and it can suppress proteinuria synergistically with that the use of low-protein diets to treat CKD patients has no effect on
ACEi.
49
Protein-restricted diets have also been shown to reduce intra- their survival after the start of dialysis.
56,57
We concur that physicians
renal and systemic hypertension.
35,50
Further studies delineating the should be concerned about patients who are losing muscle mass and
effects of protein restriction on the progression of CKD are warranted. serum proteins, but several reports document that these problems have
Regardless of the limitations of the MDRD study and other reports, we little to do with dietary protein restriction or protein intake. In fact, the
conclude that the benefit of a low-protein diet on the progression of efficacy of low-protein diets in maintaining nutrition has been well
kidney failure is not yet proved. documented.
31,34,40,58
This occurs because a well-planned low-protein
diet will provide an adequate intake of energy, and because CKD
Barriers to Protein-restricted Diet Implementation patients without complicating illnesses will activate the same
Implementation of a low-protein diet in the management of CKD is often protective/adaptive mechanisms as normal adults.
23–25
For these
neglected and its value in the planning care of CKD patients is reasons, patients with uncomplicated CKD have the same protein
underestimated.
51
There are a significant number of ‘perceived barriers’ to requirements as normal adults.
implementing dietary strategies, but none should supersede over
100 years of experience with low-protein diets in the management of CKD.
The first impediment to using dietary strategies is the conclusions of the
The weight loss, fatigue and muscle
MDRD study that a low-protein diet does not alter the progression of wasting seen in chronic kidney disease
kidney failure. As noted, this study had significant limitations and it does
(CKD) have often been misdiagnosed
not address the the other major beneficial metabolic effects of dietary-
protein restriction. Second, dietary counselling as a part of the as malnutrition, but it is the metabolic
management of patients is severely underused,
52
perhaps due to cost or
consequences of CKD, not dietary
the lack of availability of such services. However, in the US the cost of
dietary counselling is reimbursed by Medicare. Table 2 outlines the dietary
insufficiency, that cause muscle
requirements for patients with CKD. The MDR of protein intake and
wasting in CKD patients.
calories in normal adults or those with uncomplicated CKD is 0.6g of
protein/kg/d and 30–35kcal/kg/d.
3
The recommended amount of protein
intake rises up to 0.8g of protein/kg/d when there are concurrent illnesses, The term malnutrition deserves special mention. It is defined as
use of steroid therapy or proteinuria above 5g protein/d. abnormalities caused by insufficient caloric intake or imbalanced
diet, so malnutrition should be corrected by increased dietary
Another perceived barrier to dietary strategies is the notion that CKD protein/caloric intake. However, CKD-induced muscle wasting is a
patients are unwilling to adhere to the diet. A change in life-long catabolic process that occurs because cellular pathways are
EUROPEAN RENAL DISEASE 2007 43
Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76