I was advised by a friend who is a doctor (Osteopathic Physician) to check out my vitamin D-3 levels. We see each other socially about once a year and he is aware of my CIDP. One look at me and he suggested a blood test called 1,25 hydroxy to check my D-3 with levels between 40-70 as ideal based on current research he’d read. If it was low he recommended using a form of nonprescription D-3 called ‘cholecalciferol’ at 4000 IU/daily. I discussed it with my neuro and he was not aware of the research, however that day his nurse practitioner was with him; she had read about it and suggested I get the test. I got the test and it was well below 40. Dr. said it would ‘do no harm’ to try it and I took 4000+ IU/daily for several months and the next test showed a jump to about 60. My neuro asked me if “I felt better” and the answer, sorry to say was …”No” This was a few years ago and I still take 4000 IU/daily to keep up the old D-3. My regular blood tests have never shown my “D” to be low but I’m more aware of the need to ‘get some sun’ as I spend 90 percent + of my time indoors. That is all I know about D and D-3 ~ I asked my neuro why I can have normal D but low D-3 and he didn’t know.
I don’t want to get involved in the whole vitamin thing as it seems quackery abounds… however, my health-conscious wife (daughter of a doctor and raised in a home where ‘health’ – not medicine – was dinner table discussion) goes to a doctor who Rx’s a vitamin formulary based her personal needs. My wife already knew about D-3 and has been taking it for years but never heard of a neuro-connection. I take a multi-vitamin and my D3 fairly regular but have problems with niacin and some of the B’s. To me that says some are good for me, some aren’t, some interact with each other, and others probably don’t do anything at all. The formulary approach makes sense to me. Certainly vitamin deficiencies and over-dosing can cause problems.

I’ve been on IVIG for many, many years (2g/Kg ea 6 weeks for CIDP). My friend, a doctor took one look at me and said “Get your D3 level checked and if it is take use a Cholecalciferol supplement.” I had it checked and my D3 was quite low. Discussed w/my neuro and he said it would do no harm to take OTC supplement. I take 3000 IU daily and don’t notice any difference but my numbers went up. Evidently there is D and the seldom checked D3? Worth looking into. After all one never knows when something will actually work wonders. I keep looking and listening and sharing. Regards