Shanghai Green
Shanghai Green (also known as "Qing Cai" or "Shanghai Bai Cai") is indeed a vegetable relatively high in calcium.
Nutritional Content (per 100g of fresh product, approximate values)
Calcium: approx. 100–120 mg
Magnesium: approx. 20 mg
Potassium: approx. 250 mg
Vitamin C: approx. 20–30 mg
Vitamin K and Folate: also relatively abundant
Comparative Reference
Spinach: contains about 49 mg of calcium per 100g, but it is high in oxalic acid, which reduces calcium absorption.
Shanghai Green: has a higher calcium content than spinach and contains less oxalic acid → making its calcium more easily absorbable.
Milk: contains about 100 mg of calcium per 100g, similar to Shanghai Green, but Shanghai Green has better bioavailability.