EDITORIALNutritional Intervention in ChronicKidney
DiseaseDIETARYPROTEINRESTRICTIONhasbeenprescribedinchronickidneydisease(CKD)
for a century, and a low-protein diet(LPD) or supplemented very
low-protein dietwith ketoanalogs of amino acids (SVLPD)
hasbeenprescribedfor four decades. It was arguedthat such aregimen
may beassociated witha de-teriorationof nutritional status.
Suchinterven-tion is uncommon nowin the United Statesand in most
European countries, in which a stan-darddiet with0.8g/kg/dayof
proteinis com-monly used. At the same time, most patientspresent
signs of protein-energy malnutritionatthe start of renal
replacement therapy (RRT),even if they have consulted a
nephrologist inthe preceding months or years. The Comprehen-sive
Dialysis Study, which is part the United StatesRenal
DataSystem(USRDS) 2008datareport,involved a special collection of
data on the nutri-tion, activity, andqualityof lifeof patients
whoinitiatedRRT between 2005and 2007.The rstresults showed that at
the start of RRT, 60%ofpatientsexhibitedaserumalbuminlevel low-er
than35 g/L, andin80%of these patients,the alimentary intake was
below the actualrecommendations.1In contrast, during the last
several decades,no study demonstrated that LPDor SVLPDwas
associatedwithmalnutrition. Therst andsecondanalyses of the
Modicationof Diet inRenal Diseases (MDRD)-Studyconcludedthatsuch a
regimen is safe in uncomplicated andcarefullymonitoredcases.
Short-termfollow-upof SVLPDpatients showed no adverse nutri-tional
effects after patients started dialysis, orduringandafter
transplantation. Onecouldob-ject that these patients were carefully
selectedandmonitored. Thislastpointisimportant, be-cause a
nutritional survey should be the mainfeature of an adequate,
long-term follow-upof CKDpatients beforeRRT. The implemen-tation of
nutritional guidelines is associatedwithbetter results.2Areviewof
the literatureregarding protein intake and CKDconrmedthat
nutritional therapy is effective to reducecomorbidities associated
with CKD: nutrition,phosphate intake, proteinuria,
andcardiovascu-lar riskfactors.All thereports fromthis
symposiumdemon-stratethat nutritional interventioninCKDpa-tients is
not an outmoded therapy based onantiquated clinical studies, and
that a supple-mented, protein-restricted diet has its place ina
therapeutic approach. The long-termfollow-up of patients in
previous studies conrmedthesafetyandnutritional adequacyof
thesedi-ets, and recent clinical studies of nondiabeticand diabetic
patients led to the same conclu-sions. Theexperimental andclinical
studies re-portedinthis issue of the Journal illustrate allthe
mechanisms (and newdirections) involvedinthe benecial effects of
LPDs supplementedwithketoacids/aminoacids: theeffectsonpro-teinuria
and endothelial dysfunction, speciceffects of branched-chain amino
acids, effectsof ketoacids/aminoacids onasymmetricdime-thylarginine
and body fat mass, and effects onglomerular structure andrenal
brosis. Clinicalstudies conrm previous studies and meta-analyses:
SVLPDs delaythe time toRRT, andcould be of economic importance.
Clinicalstudies also conrmthe positive effects sug-gested
byexperimental data interms of obesetransplanted patients, diabetic
patients, and thepreservation of renal function in
peritonealdialysis patients. To help nephrologists andP. C.
received a consultancy fee.This article was published as part of a
supplement sponsored by anunrestricted educationalgrant from
Fresenius Kabi.2009bythe National KidneyFoundation, Inc. All
rightsreserved.1051-2276/09/1905S-0001$36.00/0doi:10.1053/j.jrn.2009.06.018Journal
of Renal Nutrition,Vol 19, No5S(September), 2009: ppS1S2
S1dietitians, theexpert panel proposes aconsensusstatement on keto
acid therapy in diabetic ornondiabeticpredialysis patients
andinnephroticsyndrome.In conclusion, nutritional interventions
andspecicallysupplementedverylowproteindietshave many proven
advantages in terms of theprogressionofrenal
failure,bettermetabolicandendocrine control, and decreased
proteinuria.Patients are in need of a detailed nutritionalsurvey by
dietitians and nephrologists. This shouldbe the case for all CKD
patients, but especially forSVLPDpatients, toavoidmalnutrition.
Towardthis goal, all the data reportedinthis issue byinternational
experts on this topic will help.and will offer some newdirections
for futureresearch.Philippe Chauveau, MDNephrology Department,
Hopital Pellegrin andAurad-Aquitaine, Bordeaux, FranceReferences1.
Kutner NG, Johansen KL, Kaysen GA, et al: The Compre-hensive
Dialysis Study (CDS): a USRDS special study. Clin J AmSoc Nephrol
4:645650, 2009.2. Campbell KL, Ash S, Zabel R, McFarlane C, Juffs
P,Bauer JD: Implementationof standardizednutritionguidelinesbyrenal
dietitians is associatedwithimprovednutritionstatus.J Ren Nutr
19:136144, 2009.EDITORIAL S2
