Calcium and iron are well known in helping us guard against cancer and fight aging. But don't totally depend on spinach for calcium and iron cause it contains a chemical called oxalic acid which binds with iron and calcium and thus reduces the absorption of these minerals.
If you want your body to absorb minerals more efficiently then Eat spinach with vitamin C foods such as tomatoes or any citrus fruit which works really great.
Intake of just one or two cups of spinach everyday helps your immune system to be healthy and also beneficial to vision. Vitamin A in spinach also assists in slowing down the onset of wrinkly skin and helps you fight aging.
It also provides riboflavin, vitamin B6, Folate, magnesium, and carotenoids such as beta carotene, lutein, and zeaxanthin which are well known to fight against aging.