Abstract
Objective: Patients with kidney stones are counseled to eat a diet low in animal protein, sodium, and oxalate and rich in fruits and vegetables, with a modest amount of calcium, usually from dairy products. Restriction of sodium, potassium, and oxalate may also be recommended in patients with chronic kidney disease. Recently, plant-based diets have gained popularity owing to health, environmental, and animal welfare considerations. Our objective was to compare concentrations of ingredients important for kidney stones and chronic kidney disease in popular brands of milk alternatives. Design and methods: Sodium, calcium, and potassium contents were obtained from nutrition labels. The oxalate content was measured by ion chromatography coupled with mass spectrometry. Results: The calcium content is highest in macadamia followed by soy, almond, rice, and dairy milk; it is lowest in cashew, hazelnut, and coconut milk. Almond milk has the highest oxalate concentration, followed by cashew, hazelnut, and soy. Coconut and flax milk have undetectable oxalate levels; coconut milk also has comparatively low sodium, calcium, and potassium, while flax milk has the most sodium. Overall, oat milk has the most similar parameters to dairy milk (moderate calcium, potassium and sodium with low oxalate). Rice, macadamia, and soy milk also have similar parameters to dairy milk. Conclusion: As consumption of plant-based dairy substitutes increases, it is important for healthcare providers and patients with renal conditions to be aware of their nutritional composition. Oat, macadamia, rice, and soy milk compare favorably in terms of kidney stone risk factors with dairy milk, whereas almond and cashew milk have more potential stone risk factors. Coconut milk may be a favorable dairy substitute for patients with chronic kidney disease based on low potassium, sodium, and oxalate. Further study is warranted to determine the effect of plant-based milk alternatives on urine chemistry.
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Key Points
People with kidney stones are counseled to eat a diet low in animal protein, sodium, and oxalate and rich in fruits and vegetables, as well as a modest amount of calcium, usually from dairy. Recently, plant-based diets have gained popularity. Unfortified non dairy milks have less calcium than dairy, although many commercially available non dairy milks are calcium fortified. However, there is concern that some nut-based milks may have a high oxalate content. The objective was to evaluate the concentrations of ingredients which promote (sodium, oxalate) or inhibit (calcium, potassium) stones in milk alternatives. In addition, the concentration of ingredients that should be monitored in CKD (sodium, potassium) were assessed. The results suggest that oat, rice, macadamia, and soy milk may be appropriate substitutes for stone-formers. For patients with CKD, coconut and flax milk compares favorably with dairy milk based on the lowest sodium, potassium, and oxalate levels. Macadamia milk is another option for patients who are restricting potassium and oxalate, but has a higher sodium content than coconut milk. Limitations of this study include the lack of data on citrate, a stone inhibitor. In addition, data were not available for the magnesium, chloride, phosphorus, and sulfate contents for all of the products examined in this study. Coconut and flax milk may be a favorable dairy substitute for patients with CKD based on low potassium, sodium and oxalate.