Green leafy vegetables such as spinach and chard are a great source of vitamin K, the vitamin that helps regulate the transport of calcium into bones, keeping it from accumulating in the urine to form kidney stones. These same green leafy vegetables, however, are also a major source of the oxalates that combine with calcium in the urine to form stones. Since people who have kidney stones generally need to avoid their leafy greens, how can they get their vitamin K?
Our bodies don't need vitamin K in food every single day. One to two three servings of vitamin K-rich foods every week is enough for people who are able to eat spinach, Swiss chard (silverbeet), dandelion greens, or collards. But it's also possible for people who can't eat most greens to get their needed 630 micrograms per week (for women over 19) to 890 micrograms per week (for men over 19) with other plant foods. All that is needed is a total of nine servings per week of any combination of raw or cooked Brussels sprouts, raw or cooked cabbage of any kind, raw or cooked broccoli, lettuce of any kind, asparagus, or cucumbers.
You could dump all of these vegetables into the blender and make a green drink for kidney stones. Most people prefer to eat some cooked cabbage or broccoli and to drink a few servings or cabbage juice, which may be combined with apple or carrot juice (but not beet) to make an interesting alternative to salads and cooked vegetables.
If you are sensitive to the odor-causing sulfur compounds in vegetables in the cabbage family, then you will need to eat at least a serving (one cup, or about 80 grams) of lettuce every day. And if you can't get your salad every day, making sure there is no addition of spinach to your salad (too many oxalates), then take a vitamin K supplement. Just a single 500-microgram tablet or capsule twice a week is enough.