Kale
Food · Vegetable · Food, Typed Supps
A calcium source your body genuinely absorbs, unlike spinach’s.
Stage by stage
- Intake (Fibrous leaf structure): Chewing breaks down its fibrous leaf structure.
- Stomach (Releases vitamins & calcium): Digestion releases vitamin K, vitamin C, and calcium.
- Small intestine (Low-oxalate, well-absorbed calcium): Kale’s calcium absorbs notably better than spinach’s because it contains far less oxalate.
- Bone & immune tissue (Vitamin K & C support): Absorbed calcium and vitamin K support bone-related proteins; vitamin C supports immune function.
Timing
Lightly cooked or raw both retain most nutrients.
Time to effect
- Weeks: Regular intake contributes to vitamin K and calcium status.
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, Low-FODMAP, Gluten-free.
In season
October to March in the northern hemisphere, April to September in the southern.
Satiety
The satiety index is measured on 240 kcal servings. At 26 kcal per 100 g that is 938 g 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 £2.5 per kg, as a band midpoint rather than a price.
Key nutrients
Nutrition per 100g
- Calories: 25.6
- Protein: 3.3g
- Carbohydrate: 0.3g
- of which sugars: 0.3g
- Fat: 0g
- of which saturated: 0g
- Fibre: 5.2g
- Sodium: 86mg
Food vs. supplement
Kale’s calcium is absorbed at a similar or even better rate than milk’s, gram for gram — unlike spinach, whose oxalates block much of its own calcium and iron from being absorbed.
Kitchen tip
Massaging raw kale with a little oil or acid for a minute or two breaks down its tough fibres and makes it noticeably less bitter.
Common myth
“All leafy greens have the same absorbable calcium as kale.” In reality: Oxalate content varies significantly between leafy greens — spinach and swiss chard block calcium and iron absorption much more than kale or bok choy.
Recipes that use it
More in Vegetable
In the glossary
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