Many common vegetables contain very little vitamin K, making them easy choices if you’re managing your intake for medication like warfarin. Root vegetables, most fruiting vegetables (tomatoes, peppers, cucumbers), and a few surprising options like cauliflower and iceberg lettuce all come in well under 30 mcg per serving. The key is knowing which vegetable families tend to be low and which ones to watch out for.
Vegetables With the Least Vitamin K
The following vegetables all contain fewer than 30 mcg of vitamin K in a standard half-cup serving (or one cup for lettuce and tomatoes):
- Grape tomatoes, raw: 6 mcg per cup
- Cucumber with peel, raw: 9 mcg per half cup of slices
- Cauliflower, raw or cooked: 9 to 10 mcg per half cup
- Carrots, raw or cooked: 10 mcg per half cup
- Artichoke hearts, cooked: 12 mcg per half cup
- Iceberg lettuce: 14 to 17 mcg per cup shredded
- Avocado, sliced: 15 mcg per half cup
- Raw celery: 15 mcg per half cup
- Green peas, cooked: 21 mcg per half cup
- Green beans, canned: 26 mcg per half cup
- Canned peas: 26 mcg per half cup
Potatoes, sweet potatoes, corn, beets, mushrooms, onions, and bell peppers are also very low in vitamin K, generally coming in under 5 mcg per serving. These rarely appear on vitamin K food lists because their amounts are so small they’re essentially negligible.
Why Lettuce Choice Matters
Not all salad greens are equal when it comes to vitamin K. Iceberg lettuce contains roughly 17 mcg per cup of shredded leaves, making it the lowest common option by a wide margin. Romaine lettuce has about 48 mcg per cup, nearly three times as much. Butterhead (Boston or Bibb) lettuce is even higher at around 56 mcg per cup.
The darker and more leafy the green, the more vitamin K it contains. Spinach, kale, collard greens, and Swiss chard sit at the opposite end of the spectrum, with some delivering over 500 mcg in a single cup. If you enjoy salads but want to keep vitamin K low, iceberg lettuce is the most predictable base to build on.
Cauliflower: The Cruciferous Exception
Cruciferous vegetables like broccoli, Brussels sprouts, and kale are typically high in vitamin K, which leads many people to avoid the entire family. Cauliflower is the notable exception. A half cup of cauliflower contains only about 9 to 10 mcg of vitamin K, while the same amount of cooked broccoli delivers around 110 mcg. The difference comes down to color: vitamin K is concentrated in the green, chlorophyll-rich parts of plants. Cauliflower’s white florets simply don’t produce it in the same quantities. This makes cauliflower a versatile substitute when recipes call for broccoli or other green cruciferous vegetables.
How Cooking Affects Vitamin K Levels
Vitamin K is fat-soluble and relatively heat-stable, so cooking doesn’t destroy it the way it can destroy vitamin C. Research on different cooking methods found that most vegetables retain between 70% and 100% of their vitamin K after boiling or steaming. Carrots, for example, retained about 85% of their vitamin K after boiling and 70% after steaming. Zucchini held onto roughly 87% to 90% regardless of method.
In practical terms, this means cooking won’t significantly lower vitamin K in your vegetables, but it won’t increase it in a meaningful way either. A low vitamin K vegetable stays low whether you eat it raw, steamed, or roasted. The one thing to be aware of is portion concentration: when you cook leafy greens, they shrink dramatically, so you might eat far more volume than you would raw. That’s less of a concern with root vegetables and cauliflower, which don’t reduce much in size.
Fresh, Frozen, and Canned Versions
Frozen vegetables are picked and flash-frozen at peak ripeness, which locks in most of their vitamins and minerals. The brief blanching step before freezing doesn’t significantly alter vitamin K content. Canned vegetables are similarly stable when it comes to fat-soluble vitamins. Research from Colorado State University confirms that the canning process has a negligible effect on vitamins A, E, and K. So whether you buy fresh carrots, frozen peas, or canned green beans, the vitamin K content per serving stays roughly the same. Choose whichever form is most convenient without worrying about a major difference.
A Simple Pattern to Remember
The easiest rule of thumb: the greener and leafier a vegetable is, the more vitamin K it contains. Vitamin K is tied to chlorophyll, the pigment that makes plants green. This is why kale, spinach, and parsley are among the highest sources, while pale, starchy, or brightly colored vegetables tend to be low.
Vegetables that are consistently safe choices for a low vitamin K approach include:
- Root vegetables: carrots, potatoes, sweet potatoes, beets, radishes
- Fruiting vegetables: tomatoes, cucumbers, bell peppers, zucchini, corn
- Alliums: onions, garlic
- Others: cauliflower, mushrooms, iceberg lettuce, eggplant
If you’re tracking vitamin K because of blood-thinning medication, the goal isn’t necessarily to avoid all vitamin K. It’s to keep your intake consistent from day to day so your medication dose stays effective. Knowing which vegetables are low gives you flexibility to eat freely from that group without worrying about large swings in your daily totals.