Low folic acid in blood test. Should I worry?

[WWGD]

I went to GP with tummy troubles - bowel movements not yet wholly returned to normal five weeks after a tummy bug - and they ordered a fecal test and blood test. Stillwaiting for first of these but just got text from GP saying blood test showed folic acid deficiency and they have prescribed a supplement for me to pick up.
It's impossible to actually talk to anyone. But i hate taking things without knowing how necessary they are, or the reason for the deficiency, or what happens if I don't take them etc.
Just wondered if anyone has any insight? Presumably if blood test showed cancer markers (my main worry given it's bowel stuff) they would have said that when messaging me re folic acid deficiency?

They are very necessary.

If you don’t take them you can end up with confusion, memory loss, depression and dementia.

folate deficiency anaemia is quite common tbh. Drinking too much, poor diet or even taking some medications can cause this as medications may affect absorption. Folate deficiency can also cause diarrhoea.