hi ww! lol better not call me the d3 expert on this forum! 54... i will take that as being in nmol/L units and agree that it sounds insufficient even for preventing osteoporosis, never mind optimizing immune function.
so. 400 per day is not enough, australia recommends 1000IU, health canada recently bumped it up to 2000IU, and there are a fair number of authors who would argue 4000IU gets used up daily and needs to be replenished through dietary, sunlight (of a minimum strength), and if needed, supplementary inputs.
we've heard about marshall's ideas and back when it was first mentioned to me, i looked at his rationale and study design and decided he was out to lunch, so i don't really want to go back over it again here, if ppl don't mind.
you can bump your level up 50 nmol/L in a short time by taking drops of highly concentrated liquid for a short period. as we know, i did 50,000IU per day for 10 days in 2006. i followed it up with 4000IU per day for some time, rather sporadically depending on season and other things going on.
last time i got structured about taking d3, i had become more concerned about balancing calcium and magnesium. i tried to take more but it made my kidneys ache (at least, my back hurt, and when i stopped the extra minerals the ache retreated).
so yes, do take calcium magnesium and zinc. try to get as much of your d3 from sun and diet as you can, and be careful about your calcium and magnesium balance.
i think the best bet site advises 1200mg calcium and 600-1200mg magnesium. elsewhere, i've seen products with a mag to cal ratio of 2:1, which i'm getting curious about. especially since i don't see how to get more than approx 600mg magnesium in as supplements without spending all day on the toilet.
best bet site also recommends that ms patients pay attention to their zinc levels. i second this.
you also need to be careful to get some of your magnesium intake at a separate time of day from your d3. i always had taken them together and apparently that is part of why my other magnesium needs were affected. so yes, take a hefty cal-mag-zinc combo with your d3, but take some of your daily mag at a different time so the d3 doesn't snatch it all up.
i *HOPE* that is more helpful/less confusing lol!