Based on a study run at Massachusetts General Hospital, supplementation is recommended because 93% or individuals were vitamin D deficient even after multivitamin use. Now when you consider that most of us (as we age and have work or other responsibilities) spend less time in the sun and don't eat many foods high in vitamin D, you may already be vitamin D deficient. This should justify supplements easily.
Along with other problems, vitamin D deficiency can be extremely problematic for calcium and potassium absorption, both important substances for normal cell functioning and bone strength. If you add that normal nerve, muscle and immune functioning are also dependent on vitamin D, we get another justification for supplementation.
We have found that many individuals with neuropathy also have vitamin D deficiency. To alleviate this problem, we recommend the following supplementation:
Vitamin D3 (active form is best to supplement) at 800IU per day.
You will find many benefits from this supplementation, including possible prevention or possible improvement of peripheral neuropathy.