Dietary Restriction for Recurrent

Nephrolithiasis

Iris Thiele Isip Tan MD, FPCP, FPSEMClinical Associate Professor, UP College of Medicine

Section of Endocrinology, Diabetes & MetabolismDepartment of Medicine, Philippine General Hospital

Increase fluid intake to ensure a urine volume of at least 2 liters/day

pH < 5.5 pH > 6.0

Calcium >170 mg/L

♀>250 mg/24h ♂>300 mg/24h

Oxalate >40 mg/24 h

Citrate <350 mg/24 h

Phytate <1 mg/24h

Urate >650 mg/L

♀>600 mg/24h ♂>800 mg/24h

Grases et al, Nutrition Journal 2006;5:23

Urinary Lithogen Factors

pH < 5.5

Calcium oxalate

Uric acid

Cystine

Calcium oxalate/uric acid mixed

Animal protein

Citrus juicesSoftdrinks

Citric acid rich

beverages

Grases et al, Nutrition Journal 2006;5:23

pH > 6

Vegetarian dietCitrus juicesSoftdrinks

Citric acid rich beverages

Grases et al, Nutrition Journal 2006;5:23

Calcium oxalate

Hydroxyapatite

Brushite

Calcium oxalate/Hydroxyapatite

mixed

Oxalate >40 mg/24h

Oxalate rich foodsAscorbic acid rich foods

(vit C intake >2 g/day)

Grases et al, Nutrition Journal 2006;5:23

Calcium oxalate

Spinach RhubarbPurslane ParsleySweet potatoesLambsquarters

ChivesBeet leavesAmaranth OkraGreen teaChocolate

SodiumAnimal protein

Water intake >2 li/day

Grases et al, Nutrition Journal 2006;5:23

Calcium >170 mg/L♀>250 mg/24h ♂>300 mg/24h

Calcium oxalate

Calcium oxalate/Hydroxyapatite

mixed

Hydroxyapatite

Control vit D consumption

& calcium supplements

Avoid Ca restriction in hypercalciuric patients

❖ No clear distinction between absorptive and renal hypercalciuria

❖ No prospective studies to support belief that calcium restriction leads to reduction in stone recurrence

❖ Calcium restriction induces secondary hyperoxaluria

Heilberg I. Nephrol Dial Transplant 2000;15:117-123

Avoid Ca restriction in hypercalciuric patients

❖ Predisposes to bone loss (negative calcium balance)

❖ Chronic Ca restriction might upregulate vitamin D receptors (stimulate intestinal Ca absorption and bone resorption)

❖ Other nutrients (protein, Na, oxalate and K) affect calcium excretion

Heilberg I. Nephrol Dial Transplant 2000;15:117-123

Comparison of two diets for the prevention of recurrent stones in idiopathic hypercalciuria

Borghi et al, NEJM 2002:346:77-84

low Ca dietn = 60

normal Ca, low animal protein, low salt diet

n = 60

Recurrent calcium oxalate stones with idiopathic hypercalciuria (Italy)

5-year follow-up

Avoid milk, yoghurt & cheese to reduce Ca intake 10 mmol/dayAvoid oxalate-rich foods (walnuts, spinach, rhubarb, parsley, chocolate)

TCR: 2540 kcalTotal protein: 15% Lipids: 33% CHO: 52%Ca: 30 mmol/dayNaCl: 50 mmol/dayAvoid oxalate-rich foods

Both diets allowed 2-3 liters of water/day

Comparison of two diets for the prevention of recurrent stones in idiopathic hypercalciuria

Borghi et al, NEJM 2002:346:77-84

Primary outcome measure:Time to first recurrence of symptomatic renal stone* or presence of radiographically identified stone**

* Typical renal colic, episode of hematuria, expulsion or removal of previously undiscovered stone ** Renal UTZ/abdominal flat plate yearly

low Ca dietn = 60

normal Ca, low animal protein, low salt diet

n = 60

23/60 had relapses⬇Urinary Ca

⬆Urinary oxalate

(5.4 mg/d or 60 umol/d)

12/60 had relapses⬇Urinary Ca

⬇Urinary oxalate

(7.2 mg/d or 80 umol/d)

Comparison of two diets: cumulative incidence of recurrence (%)

Borghi et al, NEJM 2002:346:77-84

0

50

0 60

40

30

20

10

6 12 18 24 30 36 42 48 54

Month

Low calcium

Normal calcium, low protein, low salt

Cum

ulat

ive

Inci

denc

e

of R

ecur

renc

e (%

)

NO. AT RISK

Low calciumNormal calcium, low protein, low salt

6060

5957

5153

4947

4646

4445

4244

3943

3341

3140

2840

Low calcium

Normal calcium, low protein, low salt

RR = 0.49 (95%CI 0.24-0.98), p=0.04

Delayed effect of intervention due to early recurrences in the highest-risk patients

Borghi et al, NEJM 2002:346:77-84

0

80

0 60

70

60

50

40

30

20

10

6 12 18 24 30 36 42 48 54

Month

Low-calcium diet — men at highest risk (n=9)Normal-calcium, low-protein, low-salt diet — men at highest risk (n=14)Low-calcium diet — other men (n=51)Normal-calcium, low-protein, low-salt diet — other men (n=46)

Cum

ulat

ive

Inci

denc

e of

Rec

urre

nce

(%)

High-risk: >5 colic episodes in the year before randomization, >10 stones before randomization or both

Citrate < 350 mg/24 h

Citrate-rich foodsCitric acid rich

beverages

Grases et al, Nutrition Journal 2006;5:23

Calcium oxalate

Hydroxyapatite

Calcium oxalate/Hydroxyapatite

mixed

Phytate < 1 mg/24 h

Phytate rich foods

Cereal germ i.e. corn germ

Cereal bran i.e. wheat cereal (100% bran)

Whole cereals i.e. wild rice

Beans i.e. whole bean, bean flour, tofu

Nuts i.e. brazil nuts

Grases et al, Nutrition Journal 2006;5:23

Calcium oxalate

Brushite

Purine rich foodsAlcoholic drinks

Grases et al, Nutrition Journal 2006;5:23

Uric acid

Calcium oxalate/uric acid mixed

Urate >650 mg/L

♀>600 mg/24h ♂>800 mg/24h

SeafoodCanned seafood (anchovies, sardines in oil, herrings)Fish roeMeatOrgan meat (liver, kidney, sweetbreads)Meat extracts, consomme, gravies

General Dietary Recommendations

❖ Daily intake of a suitable liquid volume (minimum 2 L water/day)

❖ Avoid strictly vegetarian diets

❖ Avoid excessive animal protein diets

Grases et al, Nutrition Journal 2006;5:23

High Protein Intake

Hyperuricosuria (purine overload)

Hyperoxaluria(↑ oxalate synthesis)

Hypocitraturia(↑ tubular citrate

reabsorption)

Hypercalciuria

↑ bone resorption

↓ tubular Ca reabsorption

↑ Ca filtered load

Heilberg I, Arq Bras Endocrinol Metab 2006;50:823-31

General Dietary Recommendations

❖ Avoid excessive salt (NaCl) consumption

❖ Avoid excessive vitamin C and/or vitamin D consumption

❖ Consume phytate-rich products (natural dietary bran, legumes and beans, whole cereals)

Grases et al, Nutrition Journal 2006;5:23

Thank Youhttp://www.endocrine-witch.info