Can Leafy Greens Like Spinach Cause Problems?
This is a question we get frequently at PEERtrainer. Since we’re such large supporters of a nutrient-dense, vegetable-rich diet, and highly encourage loading up on dark leafy greens, it can throw people for a loop when they read elsewhere that this may be harmful!
Whenever I see this question, I always know that the root concern about these great vegetables is their oxalate content. Oxalate is a compound found in a number of vegetables and other plant-based foods. What oxalate does is bind the minerals in these same foods and render them unable to be absorbed. This is potentially bad news, and it’s the main reason why leafy greens aren’t always the best source of calcium or iron even though they’re usually rich in these nutrients. The oxalate binds much of them and we don’t absorb them.
We absorb small amounts of oxalate into our bloodstream, but our kidneys efficiently filter it out to be excreted in the urine. Just like in the gut, the oxalate will bind calcium. In the rare, susceptible individual, the calcium oxalate that forms can cause kidney stones. This is not common, though.
There is no other danger associated with oxalate intake, despite the fears spread around the internet. Furthermore, we know from research that the people with the highest intakes of vegetables, including dark leafy greens, tend to be the healthiest people too. If oxalate was a big problem for the majority of people, we wouldn’t see this trend!
So keep eating your greens–the oxalate is mostly harmless, and the veggies are overwhelmingly good for you!