Do you recommend dietary changes to your patients with recurrent kidney stone disease who consume coffee and low oxalate teas daily?

Thank you for your question. Many patients get tired of drinking water and would prefer coffee, low-oxalate tea, or other beverages instead. Studies have shown no difference in whether the water is hard or soft. Coffee and low oxalate tea do not seem to increase stone passage either. There is some data that soft drinks such as colas may increase stone passage. I encourage my patients to drink water, but I do not prohibit other liquids, thinking the volume and flow rate are more important than the type of beverage. The amount of urine a stone patient should make daily has been studied many times with many different results. In general, we are looking for a minimum of 2 L/day.

It should be noted that the above data is predicated on false endp...

I don't consider either coffee or low oxalate teas to be important diet factors in calcium oxalate stone disease. I always first counsel to have adequate dietary calcium (1,000 to 1,500mg per day) through dairy or calcium tablets with meals. I only recommend limiting high oxalate foods for patients with high normal or high urine oxalate in 24-hour urine assessments. Patients become confused and frustrated if the recommended diet changes contain too many details or are too limiting. I use 24-hour urine data to focus on a couple of specific diet changes that are most likely to reduce their risk profile; usually increasing urine volume and restoring dietary calcium.

I tend to focus on urine volume and sodium rather than specifically oxalate unless their oxalate is very high on the 24-hour urine. A plant-based diet has multiple benefits, especially in older adults but this comes with a cost of a higher oxalate load. Since sodium consumption is overall higher in US society, I do tend to focus on this as well as on the urinary volume. I also specify the importance of avoiding calcium tablets which I find seems to be a common prescription from a lot of primary care and I assume this is given by them for osteoporosis. Another common OTC seems to be Vitamin C tablets which I also like for patients to avoid.