There are several deficiencies which can cause ridges in the nails. They can also be a normal quirk of a persons genetic make up (I have ridged nails and have had them checked out and there is no medical cause for them!).
Yours could be from several causes and to find out the cause you need to see a doctor.
The ridges can show deficiences which occured up to 6 months ago as they grow slowly! Useless fact of the day!!!!;Why have i got deep ridges across my nails?
I had this problem many years ago my doc told me not to work so hard as I WAS workaholic he said it was stress related not sure it's true but in the last 10 years I have done little work due to nervous breakdown and hey my nails are fine, so maybe something in it