1. Dietary Restriction
for Recurrent
Nephrolithiasis
Iris Thiele Isip Tan MD, FPCP, FPSEM
Clinical Associate Professor, UP College of Medicine
Section of Endocrinology, Diabetes & Metabolism
Department of Medicine, Philippine General Hospital

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

3. Urinary Lithogen Factors
Calcium
>170 mg/L Oxalate
pH < 5.5 pH > 6.0
>250 mg/24h >40 mg/24 h
>300 mg/24h
Urate
Citrate Phytate >650 mg/L
<350 mg/24 h <1 mg/24h >600 mg/24h
>800 mg/24h
Grases et al, Nutrition Journal 2006;5:23

4. pH < 5.5
Calcium Citrus juices
oxalate Softdrinks
Uric acid Citric
acid rich
beverages
Cystine
Calcium oxalate/ Animal
uric acid mixed protein
Grases et al, Nutrition Journal 2006;5:23

5. pH > 6
Calcium
oxalate
Hydroxyapatite
Brushite Vegetarian diet
Citrus juices
Calcium oxalate/ Softdrinks
Hydroxyapatite Citric acid rich beverages
mixed
Grases et al, Nutrition Journal 2006;5:23

6. Oxalate
>40 mg/24h
Chives
Beet leaves
Calcium Spinach Amaranth
oxalate Rhubarb Okra
Purslane Green tea
Parsley Chocolate
Sweet potatoes
Lambsquarters
Oxalate rich foods
Ascorbic acid rich foods
(vit C intake >2 g/day)
Grases et al, Nutrition Journal 2006;5:23

7. Calcium >170 mg/L Control vit D
>250 mg/24h consumption
>300 mg/24h & calcium
supplements
Water
Hydroxyapatite intake
>2 li/day
Calcium
oxalate
Sodium
Calcium oxalate/ Animal
Hydroxyapatite protein
mixed
Grases et al, Nutrition Journal 2006;5:23

8. 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

9. 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

10. Comparison of two diets for the prevention of
recurrent stones in idiopathic hypercalciuria
Recurrent calcium oxalate stones
with idiopathic hypercalciuria (Italy)
normal Ca, low animal
low Ca diet 5-year
protein, low salt diet follow-up
n = 60
n = 60
Avoid milk, yoghurt & TCR: 2540 kcal
cheese to reduce Ca intake Total protein: 15%
10 mmol/day Lipids: 33%
Avoid oxalate-rich foods CHO: 52%
(walnuts, spinach, rhubarb, Ca: 30 mmol/day
parsley, chocolate) NaCl: 50 mmol/day
Avoid oxalate-rich foods
Both diets allowed 2-3 liters of water/day Borghi et al, NEJM 2002:346:77-84

11. Comparison of two diets for the prevention of
recurrent stones in idiopathic hypercalciuria
Primary outcome measure:
Time to first recurrence of symptomatic renal stone*
or presence of radiographically identified stone**
normal Ca, low animal
low Ca diet
protein, low salt diet
n = 60
n = 60
23/60 had relapses 12/60 had relapses
Urinary Ca Urinary Ca
Urinary oxalate Urinary oxalate
(5.4 mg/d or 60 umol/d) (7.2 mg/d or 80 umol/d)
* Typical renal colic, episode of hematuria, expulsion or
removal of previously undiscovered stone
** Renal UTZ/abdominal flat plate yearly
Borghi et al, NEJM 2002:346:77-84

12. Comparison of two diets:
cumulative incidence of recurrence (%)
50
40
Cumulative Incidence
of Recurrence (%)
30
Low calcium
Low calcium
20
Normal calcium, low protein,
Normal calcium,
low salt
10 low protein, low salt
RR = 0.49 (95%CI 0.24-0.98), p=0.04
0
0 6 12 18 24 30 36 42 48 54 60
Month
NO. AT RISK
Low calcium 60 59 51 49 46 44 42 39 33 31 28
Normal calcium, 60 57 53 47 46 45 44 43 41 40 40
low protein,
low salt
Borghi et al, NEJM 2002:346:77-84

13. Delayed effect of intervention due to early
recurrences in the highest-risk patients
80 Low-calcium diet — men at highest risk (n=9)
Cumulative Incidence of Recurrence (%)
Normal-calcium, low-protein, low-salt diet —
men at highest risk (n=14)
70 Low-calcium diet — other men (n=51)
Normal-calcium, low-protein, low-salt diet —
60 other men (n=46)
50
40
30
20
10
0
0 6 12 18 24 30 36 42 48 54 60
Month
High-risk: >5 colic episodes in the year before
randomization, >10 stones before randomization or both Borghi et al, NEJM 2002:346:77-84

14. Citrate
< 350 mg/24 h
Hydroxyapatite
Calcium
oxalate
Calcium oxalate/ Citrate-rich foods
Hydroxyapatite Citric acid rich
mixed
beverages
Grases et al, Nutrition Journal 2006;5:23

15. Phytate
< 1 mg/24 h
Calcium
oxalate Phytate rich foods
Brushite 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

16. Urate >650 mg/L
>600 mg/24h
>800 mg/24h
Seafood
Canned seafood
(anchovies, sardines in oil, herrings)
Fish roe
Meat
Organ meat
(liver, kidney, sweetbreads)
Uric acid Meat extracts, consomme,
gravies
Calcium oxalate/ Purine rich foods
uric acid mixed
Alcoholic drinks
Grases et al, Nutrition Journal 2006;5:23

17. 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

18. High Protein Intake
Hyperuricosuria Hypercalciuria
(purine overload)
↑ bone
resorption
Hyperoxaluria
(↑ oxalate synthesis) ↓ tubular Ca
reabsorption
Hypocitraturia
(↑ tubular citrate ↑ Ca filtered load
reabsorption)
Heilberg I, Arq Bras Endocrinol Metab 2006;50:823-31

19. 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

20. Thank You
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