Mixed Leafy Greens
Food · Vegetable · Food, Typed Supps
A mix of different leaves, and they are not the same leaf nutritionally.
Stage by stage
- Intake (Cell walls ruptured): Chewing breaks leaf cell walls and releases carotenoids from chloroplast membranes.
- Digestion (Micelles form with dietary fat): Fat-soluble beta-carotene and vitamin K need fat in the meal to be packaged for absorption.
- Absorption (Vitamins in, oxalate binds minerals): Carotenoids and vitamin K are absorbed; oxalate from spinach binds calcium and iron in the gut.
- Use (Eyes, bone, blood vessels): Beta-carotene becomes vitamin A, vitamin K supports clotting and bone, nitrate supports vessel dilation.
Time to effect
- Hours to weeks: Nitrate-mediated blood pressure effects appear within hours; carotenoid status shifts over weeks of regular intake.
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 13 kcal per 100 g that is 1.8 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: 13
- Protein: 2.2g
- Carbohydrate: 0g
- of which sugars: 0g
- Fat: 0g
- of which saturated: 0g
- Fibre: 2g
- Sodium: 91mg
Food vs. supplement
A bag of leaves gives fibre, folate, vitamin K, potassium and nitrate together in a matrix where a little dressing makes the fat-soluble parts available. Beta-carotene supplements have a poor trial record — high-dose trials in smokers increased lung cancer risk — while the same carotenoids eaten in leaves have not shown that signal. This is one of the clearer cases where food and supplement are not interchangeable.
Kitchen tip
Dress the salad. A tablespoon of oil raises carotenoid absorption several-fold, and an undressed salad wastes most of what the leaves offer. If a bag is spinach-heavy and the point is calcium, add rocket or a low-oxalate green rather than more spinach.
Common myth
"All the leaves in a mixed bag are much the same, and spinach is the best of them for calcium and iron." In reality: Pre-washing is a real variable, not just a convenience. Bagged leaves are washed in chlorinated water, cut, and then held in modified-atmosphere packaging, which slows but does not stop degradation — vitamin C and folate decline measurably over shelf life, while the more stable carotenoids and vitamin K hold up much better. The cut surfaces and the days in the bag are also why bagged salad has a worse listeria and salmonella record than whole heads, and why re-washing at home in a domestic sink does not reliably improve on the commercial wash.
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