Spinach: The spinach nutrition is rich, but it contains the oxalic acid which will cause the zinc and the calcium to flow out of the human body.

• 菠菜：菠菜营养丰富，但因含有草酸，致食物中宝贵的元素锌与钙之结合，而被排出体外，而引起人体锌与钙的缺乏。