Why is calcium from spinach not absorbed very well?

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A woman with curly hair and a handbag shops at a busy outdoor farmer's market in Bulgaria, surrounded by stalls filled with fresh fruits and vegetables. — nutrition Vegetables are an important part of a balanced diet.

Calcium from spinach is not absorbed efficiently because it is bound to oxalates (the salts of oxalic acid).1

In the human digestive system, the absorption of calcium is significantly influenced by the chemical environment within the small intestine. While stomach acid helps convert calcium into an absorbable form, the presence of high concentrations of oxalates interferes with this process, preventing the body from effectively utilizing the calcium found in certain vegetables like spinach.1