Hi Helenab, I think our doctors are restricted in what they can prescribe by NICE guidelines which are controversially conservative, but more and more research is coming out to suggest Britons in general should be supplemented - as Jo commented in her first reply, even for those who get outdoors, the angle of the sun in the UK especially in winter means its practically impossible to get enough vitD in normal everyday life. especially as you cant get it from sun thru glass - so most people sitting in a car, or at work in a shop, factory or office all day will be missing out.
I posted the original question because it occurred to me its sort of a failure of imagination, or empathy for the realities of living with longtime severe depression - it doesnt occur to doctors the knock-on effects of basically, being bed- or house-bound for months and months on end!
I have been taking the 5000iu pd dose for about 3 weeks now, and before that a standard multivitamin. I have already noticed a reduction in pain from my knees and spine, though of course that may well be psychsomatic or the placebo effect this early on! (but Im not complaining even if it is - even a 1% pain reduction is welcome!) I have an appointment with my GP in a fortnight and will be asking him for regular vit D levels testing - I have to have monthly blood tests for lithium, thyroid, kidney function, cholesterol, etc etc.... they may as well fill up another syringe whilst they're at it! (tho' because my bipolar led to drug addiction in my twenties, its not easy for them to find a vein so that makes me kind of unpopular with the nurses and makes me feel terribly guilty since its self-inflicted).
I have done yet more reading and sounds to me that 2000iu is a perfectly safe, yet sufficiently high amount for long-term supplementation. I highly recommend the Vitamin D Council website - its really informative, data-led, and sensible. I think Vit D is a silent epidemic and could be a really big factor in why we have so many people with arthritis, osteoporosis, as well as being implicated in all sorts of other health problems like cardiovascular function, mental health, one study even suggested things like dementia and parkinsons disease could have Vit D as a contributory factor (ie, why they are so high in the West).
Good luck with the new supplement and lets keep plugging away at the medical profession to get them Vit D Aware! Im thinking of starting a new vit d thread in 'deficiencies' which ive just noticed has a discussion forum of its own on here. patient.info really is a very helpful website, I think! there's nothing else as well-designed or informative and British, as far as I can see?