I had this as well at my first bloos test. I took a supplement and tried to get in the sun more. It was June so freezing but I did make a massive effort. By my next blood tests, my levels were fine. DD idnt on any supplements for it and the pead said she doesnt need to be either.

There are foods that you can eat to help with vitamin D as well but there are not alot of them as you main source is the sun.

They are fish and egg yolks.

Hope that helps.