Radicchio
Food · Vegetable · Food, Typed Supps
Radicchio is a bitter, ruby-red salad leaf that's surprisingly packed with vitamin K -- more per bite than almost any other lettuce-like green.
Stage by stage
- Bitter First Bite (Mouth): Chewing radicchio releases sesquiterpene lactones like intybin, the compounds responsible for its signature bitterness and traditionally credited with stimulating saliva and digestive juices.
- Digestion Begins (Stomach): In the stomach, radicchio's fiber and bitter compounds slow gastric emptying as acid and enzymes begin breaking down its anthocyanins and phenolic compounds.
- Nutrient Absorption (Small Intestine): Fat-soluble vitamin K, carotenoids, and anthocyanins are absorbed in the small intestine, a process aided when radicchio is eaten alongside a source of dietary fat such as olive oil.
- Vitamin K at Work (Liver): Absorbed vitamin K travels to the liver, where it activates proteins essential for blood clotting, while circulating anthocyanins contribute antioxidant activity throughout the body.
Timing
Because vitamin K and radicchio's carotenoids are fat-soluble, eating radicchio with a drizzle of olive oil or another fat source improves absorption compared with eating it plain.
Time to effect
- Weeks: Vitamin K appears in the bloodstream within hours of eating radicchio, but consistent intake over several weeks is what meaningfully supports clotting-factor activity and other vitamin K-dependent functions in the body.
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.
Satiety
The satiety index is measured on 240 kcal servings. At 23 kcal per 100 g that is 1.0 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 108 litres of freshwater per kg, matched to "Other vegetables" in Poore & Nemecek (2018), Science 360.
Cost band
Cheap — roughly £2.5 per kg, as a band midpoint rather than a price.
Key nutrients
Nutrition per 100g
- Calories: 23
- Protein: 1.4g
- Carbohydrate: 4.5g
- of which sugars: 0.7g
- Fat: 0.3g
- of which saturated: 0g
- Fibre: 0.9g
- Sodium: 22mg
Food vs. supplement
Radicchio delivers vitamin K alongside fiber, water, and antioxidant anthocyanins in a low-calorie package; because a typical serving already exceeds 100% of the Daily Value for vitamin K, additional supplementation is unnecessary for most people and could complicate blood-thinner dosing.
Kitchen tip
Soak sliced radicchio in ice water for 10-15 minutes before serving to mellow its bitterness, or grill it briefly with olive oil to bring out a sweeter, smokier flavor.
Common myth
"Radicchio is just a red variety of lettuce, so it's nutritionally interchangeable with other salad greens." In reality: Radicchio is a chicory (Cichorium intybus), a different plant lineage from lettuce (Lactuca sativa), and it is dramatically more nutrient-dense -- roughly 255 µg of vitamin K per 100 g versus about 20 µg per 100 g in iceberg lettuce -- and contains unique bitter sesquiterpene lactones like intybin that lettuce doesn't have. Because of its vitamin K density, people on warfarin or other vitamin K-antagonist blood thinners should keep their radicchio intake consistent rather than swinging between none and large servings.
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