Napa Cabbage

Food · Vegetable · Food, Typed Supps

Napa cabbage is a light, crunchy vegetable that gives you vitamin C for your immune system and vitamin K for strong bones — for almost no calories.

Stage by stage

Chewing & Release (Mouth): Chewing ruptures napa cabbage's cells, activating the myrosinase enzyme that converts glucosinolates into biologically active isothiocyanates.
Breakdown (Stomach): Stomach acid and mechanical churning further break down the leaf's fiber matrix, releasing vitamin C, vitamin K, and folate for absorption downstream.
Absorption (Small intestine): Water-soluble vitamin C and folate are absorbed readily into the bloodstream, while fat-soluble vitamin K needs a small amount of dietary fat present to be absorbed efficiently.
Delivery & Use (Bone & blood): Absorbed vitamin K travels via the liver to bone tissue to help activate proteins involved in blood clotting and bone mineralisation, while vitamin C supports collagen synthesis and immune cell function throughout the body.

Timing

Because napa cabbage carries meaningful vitamin K, people taking warfarin or other vitamin K antagonist blood thinners should keep their intake roughly consistent day to day rather than swinging between large and negligible servings, since sudden changes can affect anticoagulant control.

Time to effect

Hours to weeks: Vitamin C from napa cabbage raises plasma levels within hours of eating it, while vitamin K's contribution to bone-protein carboxylation — and its relevance to anticoagulant therapy — reflects cumulative intake built up over days to weeks.

Allergens

None of the fourteen major allergens. Derived from what this food is, not from a product label.

Eating patterns

Fits: Vegan, Vegetarian, Pescatarian, Halal, Kosher, Keto, Gluten-free. Depends on the product: Low-FODMAP.

In season

September to April in the northern hemisphere, March to October in the southern.

Satiety

The satiety index is measured on 240 kcal servings. At 11 kcal per 100 g that is 2.3 kg of this, which is not a serving anyone eats — so the index has nothing to say about it.

Environmental footprint

0.5 kg CO2e and 76 litres of freshwater per kg, matched to "Brassicas" in Poore & Nemecek (2018), Science 360.

Cost band

Cheap — roughly £1.4 per kg, as a band midpoint rather than a price.

Key nutrients

Vitamin C
Vitamin K
Folate
Fiber

Nutrition per 100g

Calories: 10.5
Protein: 1.1g
Carbohydrate: 0.9g
of which sugars: 0.9g
Fat: 0g
of which saturated: 0g
Fibre: 1.1g
Sodium: 6mg

Food vs. supplement

Napa cabbage delivers vitamin C, vitamin K, folate, and fiber together in a low-calorie, high-water-content whole food — a nutrient combination that isolated vitamin C or K supplements don't replicate, though a supplement can still make sense for someone who needs a larger, uniform dose than food alone provides.

Kitchen tip

Add napa cabbage near the end of cooking, or eat it raw or lightly fermented (as in kimchi or salads), to preserve more of its heat-sensitive vitamin C and folate.

Common myth

"Napa cabbage is just a mild variety of regular cabbage, so it doesn't really matter which one you cook with." In reality: Napa cabbage (Brassica rapa subsp. pekinensis) is a different species from head cabbage (Brassica oleracea) — it's actually more closely related to turnips and bok choy — and per 100 g it provides meaningfully more vitamin C, vitamin K, and folate than common green cabbage, while carrying lower levels of the goitrogenic compound progoitrin than many other Brassica vegetables.