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Spinach

Oxalic acid blocks iron absorption

Per 100 g

23 kcal Energy

2.9 g Protein

3.6 g Carbs

0.4 g Fat

2.2 g Fibre

Gluten-free

Let’s cook with it → Invent something with it

What it is for

They bring water, fibre, acid and colour. Most are 80–95% water, and much of cooking them is really about managing that water.

Where it catches you out

Under a lid they cook in their own water; in a crowded pan they steam. If you want colour, give them room and take the lid off.

The knack

Mostly water: it cooks down to a tenth. What looks like too little is usually right.

Storage and health

How to keep it, and who it suits.

Keeping it

Unwashed and dry between sheets of kitchen paper, 5-7 days in the fridge; stored wet it rots in two.

Gluten-free

Spinach is naturally gluten-free.

Glycaemic index

This ingredient carries no meaningful carbohydrate, so it has no glycaemic index. On its own it will not move blood sugar; what you eat alongside it decides that.

What it works with

Pairings, and the reason for each

"They go well together" is not an explanation. Every pairing below has a chemical or structural mechanism under it.

Yoghurt →

Dairy calcium binds spinach’s soluble oxalate in the gut into insoluble calcium oxalate that is not absorbed. Crucially it runs in the useful direction: the dairy’s own calcium is not meaningfully blocked, while oxalate absorption falls.

Olive oil →

Lutein and the other spinach carotenoids are fat-soluble and require lipid for absorption.

Also works with

Garlic

Egg

Lemon

Butter

Rice

White cheese

What it fights with

Baking soda

It protects the green but destroys thiamine and vitamin C and gives a slimy texture.

Lemon

Long cooking in acid displaces magnesium from chlorophyll into olive-drab pheophytin.

What goes on top

Garlic yoghurt, olive oil, lemon, a fried or poached egg on top, crumbled white cheese, sizzled butter

Key compounds

Oksalik asit: Binds calcium and iron into insoluble salts — why spinach’s own minerals are poorly available.

Nutritionally

A basic correction: spinach’s iron looks respectable on paper but its bioavailability is very low, sometimes under 5%, because oxalate binds it in situ. Calcium absorption averages 5.1% from spinach against 27.6% from milk. Spinach is a fine vegetable and a poor mineral source.

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