did you have a leisure trip? or was it business?
glad to hear you got some tests run. that is great.
your doc is right to be cautious but i think that is a bit over cautious really. your levels are likely suboptimal (you need to be well up over 100nmol/L) and although i can't find the literature on vitamin D3 and cancer risks, i think i heard that the potential link would be something to do with if a patient's levels fluctuated wildly - you'd have to be consistent with the supplementing.
"Current research has implicated vitamin D deficiency as a major factor in the pathology of at least 17 varieties of cancer as well as heart disease, stroke, hypertension, autoimmune diseases, diabetes, depression, chronic pain, osteoarthritis, osteoporosis, muscle weakness, muscle wasting, birth defects, periodontal disease, and more."
as for the night vision, it's just another indicator of potential trouble with zinc. i was just kind of thinking, it sounds like a zinc problem, and if the night vision is bad too then it's even more likely to be a zinc problem.
make sure you get your test results, numbers and units - do NOT let them tell you 'it's normal'. average zinc in healthy controls is around 18.2 umol/L.
here are a couple of interesting abstracts:
Zinc therapy for night blindness in cystic fibrosis
This is the first report of a supplemented CF patient presenting with clinical vitamin A deficiency to be successfully treated with zinc therapy alone. Therefore in addition to retinol supplementation, normalizing serum zinc levels may be important in maintaining the vitamin A status of CF patients. The interactions and synergistic effects between the two micronutrients are discussed.
Zinc deficiency: a cause of abnormal dark adaptation in cirrhotics
Six stable alcoholic cirrhotics with serum zinc less than 70 microgram/100 ml had abnormal dark adaptation responses (mean dark adapted final threshold 3.2 +/- 0.6 versus 2.1 +/- 0.2 log lux in 21 age matched controls, P less than 0.01). Serum vitamin A ranged from 15 to 37 microgram/100 ml. Zinc sulfate (220 mg/day) was fed to three patients for 1 to 2 weeks and dark adapted final thresholds fell 0.9, 0.4, and 1.2 log lux without concurrent rises in serum vitamin A. Two patients were treated initially with oral vitamin A (10,000 IU/day) for 2 to 4 weeks, but their final thresholds fell to normal (2.1, 2.2 log lux) only after the addition of zinc for 1 to 2 weeks. The sixth patient, treated with vitamin A and zinc together, attained a normal final threshold in 2 weeks. The improvement in dark adaptation by zinc may be due to enhanced activity of previously depressed retinol dehydrogenase.
there is controversy in the literature about the utility of zinc for vision. what i get from it is, basically, if your zinc level is fine to start, adding more won't sort out your vision. if you start low (and ms patients tend to be lower in zinc on average) then adding zinc is more likely to help.
HTH! i'll be keeping an eye out for results