Oxalates have been a really hot topic lately. Hopefully I can shed some light. Oxalates, which are formed naturally in the body and are also found in the leaves of some plants. They aren’t really a concern unless you’re prone to kidney stones, and even then, the evidence isn’t very strong (study here). But since eighty percent of kidney stones are calcium oxalate stones, nephrologists (that sounds kinky/spooky!) may still recommend avoiding high oxalate foods in individuals prone to them. Recent research points to an alkaline diet (lots of fruits and veggies, minimal amounts of animal protein, and plenty of alkaline water, which can be made by simply adding fresh lemon juice to your filtered water) as one of the most effective ways to prevent kidney stones.
The bigger concern with oxalates is that they bind to calcium in the body, and may decrease calcium absorption. The highest oxalate levels are found in spinach, beet greens, and Swiss chard. Because of their high oxalate content, they are not considered a reliable source of calcium. However, not all greens are high in oxalates. Low oxalate greens include kale, bok choy, romaine, arugula, turnip greens, and others.
When in doubt, rotate! If you love spinach, beet greens or Swiss Chard in your daily smoothies or juices, just rotate kale or other lower oxalate greens into the mix for nutrient variety and to maximize calcium absorption. This strategy also applies if you’re prone to kidney stones and want to be extra special careful (as always, check with your integrative doc to find out what’s right for you).