i had not heard of this I thought vitamin D improves calcium absorption, so
even if your phosphorus intake is high, the vitamin d would help absorb more calcium.
so vitamin d improves both calcium/phosphorus absorption, so it needs to be avoided if calcium intake is poor?
Yes, mainstream research only focuses on the activated form (I think it's called 1,25 dihydroxycholecalciferol), but Peat says that form synergizes with PTH and increases prolactin. Calcium intake has to be higher than phosphate for vitamin D to not convert into the activated form (among other things as well, anything that raises PTH will increase conversion), and it is the non-activated form which has the pro-metabolic, neurosteroid-like effects.
I personally find it very hard to keep D in the non-activated form. I've felt the difference a few times... when I can tell it's not converting it feels very smooth and "stylish" but inevitably blood calcium will decrease at night or while sleeping and after that, I get the sluggish feeling of the activated form.