Juicing has become a popular health trend in the last few years. The term “juicing” or “juice cleanse” usually refers to a period of 3-10 days when a person’s diet consists mainly of fruit and vegetable juices. It is widely marketed as providing health benefits, including weight loss, flushing toxins from the body, and increasing energy. Up to now there is no strong scientific evidence to support these benefits as compared with eating fruits and vegetables. However, the gospel of juicing is here to stay, mostly through social media. Juicing is clearly an understudied phenomenon in the legitimate medical world. Is it possible that juicing is harmful? Up to now, there have been no reports of juicing-induced damage, until this issue of The American Journal of Medicine, which reports a case of oxalate nephropathy due to 6 weeks of a juicing fast.1
For this case report, we are grateful to the patient who kept detailed records of his food consumption. For over 6 weeks, he had taken a daily average of 1260 mg oxalate from beets, collard greens, kiwi, parsley, spinach, and soy products, which are considered a healthy diet and commonly consumed by people practicing juicing. Other co-factors include high vitamin C intake (2 g from supplementary vitamin C and about 0.5 g from juice), low calcium intake, and chronic kidney disease stage 3 with an estimated glomerular filtration rate of 48 mL/min. He had acute renal failure with a high serum oxalate level and required temporary hemodialysis. Fortunately, he recovered his kidney function partially, but had a loss of glomerular filtration rate by 14 mL/min due to the juicing program.1
Oxalate is a well-known nephrotoxin and is rich in certain fruits, vegetables, and nuts. […]
Is this case representing the tip of the iceberg, given that millions are practicing juicing? The index patient did have chronic kidney stage 3, had been on an unusually prolonged juicing program, and unknowingly consumed an excessive amount of oxalate. Patients with chronic kidney disease are prone to oxalate nephropathy due to diminished renal capacity to excrete oxalate. For those with normal renal function and who do not consume high oxalate juice, the risk of juicing nephropathy is likely low. However, because juice consumption enhances oxalate absorption, it is prudent to calculate daily oxalate consumption. For commercial juicing products, it is critical to label the oxalate content and provide the limit of daily consumption for consumer protection. For those who have consumed a high quantity of oxalate, an evaluation including kidney function and urinalysis with microscopic examination to look for oxalate crystals is warranted. Lastly, for physicians encountering patients with acute kidney injury of unknown origin, it is appropriate to ask, “Have you been juicing lately?”
The juicing fad has got way out of hand, with its adherents claiming all sorts of miracle benefits for it. On a theoretical basis, it’s hard to see how that could be, and as seen above, there’s a definite downside.