Which greens have the most?

What the lineup means

No green wins every row. Per cup, spinach leads on vitamin K and romaine on folate and vitamin A, kale leads on vitamin C by weight, and iceberg is mostly water but still counts as a vegetable. Pick the one you'll eat, and change it every week or two, since each brings a different mix. If your usual bowl is iceberg, half spinach is the easy upgrade.

All of it needs a little fat to get in. The carotenoids in the greens (vitamin A) and their vitamin K dissolve in fat, so a leaf salad with fat-free dressing leaves most of them in the bowl. Why fat-free dressing backfires.

Per cup or per 100 g

A cup of chopped kale weighs 21 g, a cup of spinach 30 g, a cup of shredded iceberg 72 g. So per cup, spinach has nearly twice kale's vitamin K and four times its folate. Per 100 g, kale has three times spinach's vitamin C. Both are true, and the best green is the one you rotate with the others.

Two cups of any leafy green count as one cup of vegetables in the US guidelines.

Warfarin and vitamin K

If you take warfarin, keep the amount of leafy greens steady week to week. Vitamin K changes how warfarin works. Talk to your doctor before a big change.