"Taking into account poverty is spread all over the world, to help mitigate its effects, rich countries should donate food."
Is the part in bold grammatically correct?
"Taking into account poverty is spread all over the world, to help mitigate its effects, rich countries should donate food."
Is the part in bold grammatically correct?
Yes, it is grammatically correct.
The phrase "poverty is spread all over the world" is a noun clause with "that" elided from the front. It's even clearer if you add "the fact that" in front:
"Taking into account (the fact) that poverty is spread all over the world, to help mitigate its effects, rich countries should donate food."
This noun clause is the direct object of "taking into account".
'Taking into account' is a verb phrase. It would often be followed by a conjunction to link to the following clause. Your example would make most sense as a 'that' clause:
Taking into account that poverty is spread all over the world, to help mitigate its effects, rich countries should donate food.
Having said that, there's nothing 'wrong' with the sentence as it is... we don't always use conjunctions. 'Taking into account' means pretty much the same as the verb 'considering'. You'll find that is used with or without a conjunction. If you look up 'considering' and 'considering that' in Collins dictionary you'll see they both have virtually identical definitions and examples.