Unlike some other vegetables and herbs, folklore on spinach is
hard to come by but there is some.
Spinach is well known for improving deficiencies in blood.
The iron, and more importantly, the chlorophyll content of the leaves raise the
haemoglobin content of blood significantly. During the First World War French
soldiers who had been wounded and lost blood were fed a concoction of spinach juice
with wine added to make it palatable.
Spinach powder can be used to colour some common foods green. It
is often used with pasta.
Many people believe that re-heated spinach is dangerous to eat.
There is evidence that this is true, especially for younger children. The re-heating
process causes nitrates in the spinach to be converted to nitrites. In small amounts
this is not harmful but best avoided. In large amounts it can definitely be harmful.