Isolated numbness in a single toe generally does not occur due to any
vitamin deficiency but is a result of nerve root problem for a particular dermatome from the spinal cord. Do extension (back bending) exercises, don't use soft thick mattresses for sleeping, don't sit for long in sofy cushioned sofas, keep your weight in control. If things don't improve seek consultation after necessary investigations like x ray lumbo sacral spine done. You may consult on Practo.