Table 2.

Reducing Calcium Oxalate Stone Risk After Roux-en-Y Gastric Bypass

Risk factors	Recommendations	Restrictions in RYGB patients	Solutions
Hyperoxaluria	Low-oxalate diet (<80–100 mg/day)	Component in vegetables and “healthy” foods (peanuts, bran, soy), bioavailability variable.	Patient education,a downloadable phone applications, “balance” versus avoidance
	Low-fat diet (<25% daily calories)	High prevalence of fatty foods in diets	Early satiety after surgery, patient education
	Probiotics	No commercially available Oxalobacter, unknown efficacy of Lactobacillus sp.	Most yogurts contain protein, calcium, and forms of probiotics
	Vitamin B6 (pyridoxine)	Well studied in primary hyperoxaluria; potential for neurotoxicity at high doses	Consider supplementing 50 mg/day (low dose) × 6 months then discontinue
	Calcium citrate and dietary calcium to bind enteric oxalate	Tolerability, absorption efficacy, compliance, expense	Patient education, low-dose chewable Citracal (250 mg) taken 5–6 × daily with small meals
Hypocitraturia	Potassium citrate	Tolerability, absorption efficacy, expense	Dispense as liquid or crystal/powder forms
Low urine volume	Urine output >2 L/day	Compliance, small stomach pouch	Push fluids high in citrate (i.e., lemonade), downloadable phone application reminders
High-sodium and protein diet	Low-salt (<2300 mg/day) and animal protein (0.8–1.0 g/kg/day) intake	Both ubiquitous, particularly in American diet	Patient education, follow Dietary Approaches to Stop Hypertension-style diet

^aHigh oxalate food contents can be found at: https://regepi.bwh.harvard.edu/health/Oxalate/files

Modified from Canales and Hatch.¹¹