Do not eat too much of these foods

Saw an article saying not to eat too much of these food:  Preserved egg, Strong-smelling fermented beancurd, Monosodium glutamate, Spinach, Pig liver, Barbecue food, Pickles, Cruller (Cantonese: Yau Char Kwai)

I wonder why spinach is one of them?? The explanation is:

Spinach: 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! 。（男人缺锌，会无法抬头作人，恐怖啊！） ，以及硫化氢等；这些都是蛋白质分解的腐败物质，对人体有害。

Well, I think every food that we take, it has to be moderate.  Too much water a day also will kill, as it did happened.   So just eat moderately :)