Swiss Chard, and other leafy greens, have high levels of oxalates which can cause problems by forming stones in our body, especially in our kidneys. Since oxalates are water soluble, the blanching of leafy greens like swiss chard, spinach and beet greens is recommended before eating. I’ve tried to research whether dehydrating removes oxalates and have not found any evidence that it does. I would suspect that since only H2O is evaporated from the vegetable, the oxalates would be even more concentrated in the dried greens. Can a healthy person consume small amounts of high oxalic foods without problems? Probably.