Most of the people with chronic foot problems in here do not have obvious symptoms of serious health problems (other than muscle/tendon pain etc.) and that is why we are here trying to figure it out. So,you really should see a doctor and get a thorough blood test and exam and at least go the standard route before you start listening to people like me. Then do your own research because you know the whole picture of you. No one else does. Note: I would demand a thorough blood test and exam if you haven't had one recently.
My uneducated thoughts....
Check circulation. Instead of a foot doc try someone ( a doctor) who specializes in circulation problems and the sooner the better, and get two opinions. Then look on the internet for people with Raynauds's Disease. Although this may be different some of the same dietary thing may help. Diabetes can also cause numbness in the feet.
Exercise is very good for diabetics.
According to a book I have Nutriitional Healing (and this may or may or may not be any good) Coenzyme Q10 improves oxygenation, Vit E helps circulation.
Go to a regular doc 1st
Don't wear tight shoes. Eat right, throw out the TV (I did), and exercise.