Ridges in your nail a sign of thyroid problem?

I read once where ';ridges in your nails'; could be a sign of a thyroid condition. Does anyone have a more detailed explanation of that, or perhaps a link to a photo? I wear acrylic nails but one particular nail has developed this huge ridge from cuticle to the end of my nail; my doctor paid no attention to it at all.Ridges in your nail a sign of thyroid problem?
I have ridges in my nails, but I heard that its from washing my hands too much. I also heard its from lack of some food group. Like I need more protein or something like that. I don't think its anything serious, I've had them for a long time now.