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Chapter 29: Nutrition and the Kidney in the Elderly
Patient
John E. Morley
Division of Geriatric Medicine, St. Louis University School of Medicine and GRECC, VA Medical Center, St. Louis,
Missouri
Botholderpersonsandpersonswithkidneyfailure 3. Overall, the best treatments are exercise (espe-
are highly prone to develop nutritional deficiencies cially resistance exercise), anabolic hormones (e.g.,
(Table 1). The major nutritional problem experi- testosterone and selective androgen receptor mole-
encedbybothgroupsisweightlossassociatedwith cules), and vitamin D replacement. Creatine to-
protein energy malnutrition. Renal failure patients gether with exercise improves muscle strength in
with low body mass index, weight loss, low albu- older persons. It also reduces cramps. There are no
min,andlowcholesterolallhaveincreasedmorbid- data in renal failure.
1
ity and mortality. These are classical components Thedecreasedtestosterone and vitamin D asso-
of the malnutrition, inflammation, and atheroscle- ciated with kidney disease make sarcopenia more
rosis (MIA) syndrome in ESRD. Similarly, in older likely to occur in renal failure. Insulin resistance in
persons, weight loss is associated with increased renal failure further decreases muscle anabolism
mortality. andincreasesfataccumulationinmuscle.Withag-
ing, there is a physiologic anorexia of aging with
older males reducing their caloric intake by a third
3
WEIGHTLOSS andfemalesbyaquarterovertheirlifespan. There
aremultiplecausesofthisphysiologicanorexia.Ag-
The causes of weight loss in older persons are as ing is associated with a decline in taste and olfac-
2
follows : cachexia, anorexia, sarcopenia, and dehy- tion. With aging there is a decrease in adaptive re-
dration. laxationofthefundusofthestomach,resultingofa
Sarcopeniaisthelossofmusclemassthatoccurs quicker filling of the antrum and early satiation.
with aging. It is associated with varying degrees of Thisisassociatedwithslowergastricemptyingthat
muscle power (dynapenia). Severe sarcopenia (de- occurs with large gastric volumes in older persons.
fined as appendicular skeleton lean mass corrected The satiation hormone, cholecystokinin, is in-
for height that is 2 SD below the normal value for creasedwithaging,anditismoreeffectiveatreduc-
youngpersons)occursin5to13%ofpersonsover ing food intake in older persons. The reduction in
the age of 70 yr. Sarcopenia is associated with in- testosterone in older males leads to an increase in
creased disability, and its medical costs have been leptin that can reduce food intake and increase en-
calculated to be $18.4 billion per year in the United ergy metabolism.
States. On the whole, fat older persons who main- Renal failure is classically associated with an-
tain muscle mass do fairly well, but those who are orexia because of circulating uremic toxins. In ad-
fat but have lost muscle mass (the “fat frail” or sar- dition, urea in the mouth produces gingivitis, de-
copenic obese) have worse outcomes as far as dis- creasing the enjoyment of eating. Male kidney
ability and mortality than do the thin sarcopenic. failure patients have low testosterone, increasing
There are many causes of sarcopenia (Table 2). the potential of higher leptin levels increasing an-
Theseinclude genetic factors, weight at birth, poor orexia.
energyandproteinintake,lowlevelsofactivity,de-
creased motor units, insulin resistance, decreased
anabolichormones,lowvitaminD,increasedcyto- Correspondence: John E. Morley, MB, BCh, Division of Geriatric
kines, and peripheral vascular disease. The poten- Medicine, St. Louis University School of Medicine, 1402 S. Grand
Boulevard, M238, St. Louis, MO 63104. E-mail: morley@slu.edu
tial treatments for sarcopenia are outlined in Table Copyright 2009 by the American Society of Nephrology
American Society of Nephrology Geriatric Nephrology Curriculum 1
Table 1. Nutritional alterations in kidney disease Table 3. Treatment of sarcopenia
1. Weight Loss Exercise
—Sarcopenia Aerobic
—Protein energy malnutrition Resistance
Anorexia Vibration platform exercises
Malabsorption Nutrients
Hypermetabolism Essential amino acids
Cachexia Creatine
—Dehydration Anabolics
2. Vitamin abnormalities Testosterone
—Decreased folate Selective androgen receptor molecules
—Decreased pyridoxine Ghrelin analogs
—Increased homocysteine Proteolysis Inhibitor
—Decreased niacin Angiotensin converting enzyme (ACE) inhibitors
—Decreased vitamin C Orexigenics
—Decreased 25(OH) vitamin D Megestrol
—Increased vitamin A Dronabinol
3. Trace mineral abnormalities
—Decreased zinc varietyofmedicinesinterferewithtasteandproduceanorexia.
—Decreased selenium Thecommonreversiblecausesofweightlossinolderpersons
—Decreased iron or its bioavailability are given in Table 4. Nutritional deficiencies may be related to
—Increased copper (1) the inability to access groceries—decline in mobility, poor
—Increased magnesium vision, and loss of driving privileges and (2) lack of an enthu-
4. Electrolytes siasmtocookandalossofabilitytopreparefood.Foodprep-
—Hyperkalemia
—Hyponatremia aration requires cognitive styles, dexterity, and ability to stand
5. Carnitine deficiency and/or functional impairment forlongperiods,allofwhichareoftenlackinginelderlydialysis
4
6. Lipids patients.
—Hypertriglyceridemia In renal failure, nausea, vomiting, and diarrhea can lead to
—Hypercholesterolemia weight loss. Confusion, depression, and anxiety can lead to
7. Carbohydrates decreased food intake. Generalized bone pain may limit food
—Insulin resistance intake.
—Hyperglycemia Approximately8%ofrenalfailurepatientsondialysishave
cachexia. Cachexia or wasting disease consists of loss of both
Themostcommoncauseofpathologicanorexiawithaging muscleandfat,anorexia,hypermetabolism,decreasedintesti-
is depression. Therapeutic diets are bland and further aggra- nal mobility, low albumin, low cholesterol, and elevated acute
vate anorexia. Chronic pain often limits the desire to eat. A 5
phaseproteins. Ingeneral,inrenalfailurepatients,itiscaused
Table 2. Causes of sarcopenia* by elevated inflammatory cytokine levels. Cytokines decrease
cholesterol and cause third spacing of albumin and prealbu-
Lack of physical activity min, explaining the very low levels of these circulating sub-
Lack of adequate protein ingestion stances often seen in renal failure. In renal failure, superim-
Anabolic hormone deficiency posed acute and chronic illnesses can further aggravate the
Testosterone
Dehydroepiandrosterone insulin growth factor-1 (DHEA) Table 4. MEALS-ON-WHEELS mnemonic for treatable
Growth hormone, including its muscle isoform causes of weight loss in older persons
Vitamin D deficiency Medications (e.g., digoxin, theophylline, cimetidine)
Cytokine excess (interleukin-6, tumor necrosis factor-) Emotional (e.g., depression)
Motor neuron loss Alcoholism, elder abuse, anorexia tardive
Insulin resistance Late life paranoia
Low birth weight Swallowing problems
Genetics Oral factors
Myostatin Nosocomial infections (e.g., tuberculosis)
Ciliary neurotrophic factor (CNTF) and its receptor Wandering and other dementia-related factors
Vitamin D receptor (VDR Bsm1) Hyperthyroidism, hypercalcemia, hypoadrenalism
Angiotensin converting enzyme Enteral problems (e.g., gluten enteropathy)
Androgen receptor gene (CAG-repeats) Eating problems
Cyclin-dependent kinase inhibitor 1A Low salt, low cholesterol, and other therapeutic diets
*For those wishing more details regarding the genetic factors, please see Stones (cholecystitis)
reference 2.
2 Geriatric Nephrology Curriculum American Society of Nephrology
cachexia.Peritonealdialysisisassociatedwithpotentiallylarge maintainadequateerythropoiesis,asmeasuredbyflowcytom-
losses of protein and albumin. Blood loss that is common in etry(10%hypochromicsubpopulation),intravenousironis
older persons with renal failure further contributes to protein required. Excess iron replacement should be avoided because
energy malnutrition. The role of toxins, retained during renal of the possibility that it may increase the likelihood of certain
failure, at producing catabolism is uncertain. Acidemia sup- infections.
pressesalbuminsynthesisandpromotesnegativenitrogenbal- AluminumexcessoccursmainlybecauseofuseofAl(OH)
3
ance. as a phosphate binder. Aluminum excess has been correlated
Recent studies have suggested that optimal survival in pa- with cognitive dysfunction and bone disease. Thus, low phos-
tientswithrenalfailurerequiresaproteinintakeofbetween1.1 phate diets and use of nonaluminum phosphate binders are
6
to1.4g/kgproteinperday. Inend-stagerenalfailurepatients, preferred for control of hyperphosphatemia.
anenergyintakeof35to40kcal/kgperdayseemstobeneces-
sary to maintain weight and nitrogen balance. In persons with
a lower caloric intake, amino acid supplementation may be CARNITINE
helpful.
StudiesinolderpersonswithESRDhavesuggestedthatvery Carnitineisanutrientthatisessentialforthetransportoflong
lowproteindietsmaydecreasethetimetodialysisanddaysin chainfattyacidsintomitochondria.Assuch,itplaysakeyrole
hospitalization without altering mortality. As this is a quality- in mitochondrial energy control. Serum carnitine deficiency
of-life issue, older persons should be informedofthispossibil- occurs during hemodialysis. Carnitine in hemodialysis pa-
ity to allow them to make informed choices. In severely mal- tients may reduce fatigue, increase exercise capacity, reduce
nourished anorectic patients on dialysis, intradialytic erythropoietinrequirement,reducecramps,andreducehypo-
peripheral parenteral nutrition may be a reasonable ap-
12,13
7–9 tensive events during dialysis. Carnitine seems to be safe.
proach. Available data consist of small trials and thus its use cannot be
recommendedroutinely.However,inseveremuscleweakness,
MICRONUTRIENTS cramps, dialysis hypotension, fatigue, or anemia resistant to
erythropoietin, a therapeutic trial may be considered. Carni-
In general, because caloric intake is insufficient in persons on tine can be given orally as 0.5 g daily or infused intravenously
dialysis, it may be expected that micronutrient intake may be after dialysis (10 to 20 mg/kg, three times per week).
insufficient. Virtually no patients ingest the recommended fo-
10
late and pyridoxine intakes. Niacinandseleniumintakesare
also low in persons on long-term dialysis. Vitamin C levels are TAKEHOMEPOINTS
11
reducedbyhemodialysis. 25(OH)VitaminDlevelsarelowin
ESRD. • Protein energy malnutrition is the most common nutritional problem in
Elevatedhomocysteinelevelsinepidemiologicstudieshave older persons on dialysis; it is associated with poor outcomes
been associated with cardiovascular disease, Alzheimer’s dis- • Folate and pyridoxine intakes are usually insufficient in older persons
with renal failure
ease, and osteoporosis. Renal failure itself causes elevation of • Outcomes,suchaslessfalls and improved function can be obtained by
homocysteine.Folatehasthebesteffectonreducinghomocys- keeping 25(OH) vitamin D levels 100 nmol/L.
teineinthedeficiencypatients.AdditionofvitaminB maybe
12
appropriatetopreventunmaskingoflatentvitaminB levels.
12
Elevated methylmalonic acid levels are diagnostic of vitamin DISCLOSURES
B deficiency. None.
12
Olderpersonswithrenalfailurewhoarebruisingeasilywill
benefit from vitamin C supplementation. VitaminAlevelsare
elevated in end-stage kidney disease. Elevated vitamin A levels
cause increased production of PTH and bone disease. For this REFERENCES
reason, multivitamins with vitamin A need to be avoided in
renal failure. *Key References
Asfar as trace elements are concerned, zinc, selenium, and 1. Kalantar-Zadeh K, Horwich TB, Oreopoulos A, Kovesdy CP, Younessi
iron are the most likely to be deficient in end-stage kidney H, Anker SD, Morley JE: Risk factor paradox in wasting diseases. Curr
Opin Clin Nutr Metab Care 10: 433–442, 2007
failure, whereas magnesium and copper are liable to be in ex- 2. Morley JE: Weight loss in older persons: new therapeutic approaches.
cess. Zinc deficiency in kidney failure may lead to dysgeusia, Curr Pharm Des 13: 3637–3647, 2007*
anorexia, and hypogonadism. Zinc deficiency is particularly 3. Morley JE: Anorexia and weight loss in older persons. J Gerontol A
likely to occur in patients on diuretics. Biol Sci Med Sci 58: 131–137, 2003
Iron sulfate causes anorexia and gastrointestinal distress 4. CampbellKL,AshS,BauerJD:Theimpactofnutritioninterventionon
quality of life in pre-dialysis chronic kidney disease patients. Clin Nutr
and, as such, iron gluconate is preferred. If oral iron cannot 27: 537–544, 2008*
American Society of Nephrology Geriatric Nephrology Curriculum 3
5. Morley JE, Thomas DR, Wilson MM: Cachexia: pathophysiology and 9. Eyre S, Attman PO, Haraldsson B: Positive effects of protein restric-
clinical relevance. Am J Clin Nutr 83: 735–743, 2006* tion in patients with chronic kidney disease. J Ren Nutr 18: 269–
6. Kopple JD: McCollum Award Lectures, 1996: protein-energy malnu- 280, 2008
trition in maintenance dialysis patients. Am J Clin Nutr 65: 1544–1557, 10. Andrew NH, Engel B, Hart K, et al.: Micronutrient intake in haemodi-
1997 alysis patients. J Hum Nutr Diet 21: 375–376, 2008
7. Brunori G, Viola BF, Maiorca P, Cancarini G: How to manage elderly 11. Kalantar-Zadeh K, Kopple JD: Trace elements and vitamins in main-
patients with chronic renal failure: conservative management versus tenancedialysis patients. Adv Ren Replace Ther 10: 170–182, 2003
dialysis. Blood Purif 26: 36–40, 2008 12 Savica V, Calvani M, Benatti P, Santoro D, Monardo P, Mallamace A,
8. Brunori G, Viola BF, Parrinello G, De Biase V, Como G, Franco V, Savica R, Bellinghieri G: Newer aspects of carnitine metabolism in
Garibotto G, Zubani R, Cancarini GC: Efficacy and safety of a very- uremia. Semin Nephrol 26: 52–55, 2006*
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4 Geriatric Nephrology Curriculum American Society of Nephrology
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