This is mostly for @JamesCollier
Thoughts?
Great find.
For those not wanting to read through the entire paper, the relevant conlcusion is as follows:
In conclusion, this first-ever IPD level meta-regression of the vitamin D intake–serum 25(OH)D dose-response suggests that the vitamin D intakes required to prevent vitamin D deficiency (<25 nmol/L) and inadequacy (<50 nmol/L) in 97.5% of the population (i.e., the RDA estimate) is 10 and 26 µg/day, respectively.
The 10 microgram intake is equivalent to 400 International Units (I.U.) while the 26 microgram intake is equivalent to 1040 I.U. - both far higher than the currently recommended 5 micrograms (200 I.U.) that the EFSA has been recommending.
Does this apply to vitamin D2 or D3?
I didn’t see any reference to which form. However, the paper does mention both dietary and supplemental intake, so I would assume it’s a mixture of D2 and D3 (not ideal I know). Personally I’d aim for that intake of D3 to play it safe, but even if it’s all in D2 form, it’ll still be a big improvement for most.
Good read, thanks.
As they don’t distinguish between D2 and D3, it’s likely that they are looking at typical dietary intakes which will include both.
This is more evidence that the recommended intakes of vitamin D should be higher. Based on a 2000 calorie per day intake, Huel provides a level of vitamin D within the recommended intake range.
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Not going to lie but I still think the RDA for vitamin D is way too low to achieve decent optimal levels, especially in Britain with our lack of sun for half the year…
I supplement 10,000IUs per day which grants me a Blood level of 108nmol/L, vitamin D should always be above 75nmol/L ideally to prevent signs of deficiency. 
Just to add, 1200IUs per day got me to 40nmol/L, which is definitely deficient.
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From what I’ve seen, your recommendation of 75+ nmol/L is a good one - optimal range I’ve seen is 75-88 (which is 30-35 ng/ml for those whose tests come back in that unit).
However of note is that vitamin a and vitamin d doses are somewhat linked. Various recommendations are thrown around - some say, when both are taken in International Units (I.U.), an optimal a to d ratio is between 5:1 and 8:1. I personally have had more luck at an intake level of 2:1 to 2.5:1 (as suggested in The Perfect Health Diet) as vitamin K2 is also synergistic with both of these. As such, at a minimum, with 10000 I.U. of vitamin D, you’d want ~20000 I.U. of vitamin A - an amount that would pose toxicity risks of using preformed retinal, retinol or retinyl forms. Beta carotene would be fine though. I aim for 3000 I.U. per day of vitamin D and 6000 I.U. per day of vitamin A.
The laboratory i work in quotes >50 nmol/L as being sufficient as per NOS guidelines:
Although there are no real dangers of toxicity at levels less than 150nmol/L (very rarely do i see levels higher than this, even in people being given large bolus injections)
The NHS actually have a lose guideline of keeping it above 75nmol/L, it actually has that stamped all over my blood test printout.
I really also wouldn’t worry about “ratios” either, I think its an individual thing to a point.
https://www.vitamindcouncil.org/i-tested-my-vitamin-d-level-what-do-my-results-mean/
http://www.endmemo.com/medical/unitconvert/Vitamin__D.php
I’d say up to 150nmol/L is still pretty optimal, not overdose, anything above that isn’t going to achieve much positive though. According to the blood lab report they class overdose as 300+nmol/L and even then the worry is too much calcium being absorbed.
The links might help you out a little. I know there from the US but still.
Also worth noting my Dr who is helping me out with testing my vitamin D was actually really happy with my higher level.
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The literature you sent also states 75+nmol/L as being better. 
I doubt there is much evidence that a vitamin D level between 50 and 75 makes any difference clinically. Bare in mind different laboratories/hospitals will have different recommended cut-offs. Where I work a vitamin D of >50 would be sufficient and we wouldn’t suggest supplementation.
Also worth remembering that 25-OH vitamin D is only a measure of stores (and not 100% accurate as its only what is circulating at the time). You can have as much stores as you like but the active form 1,25 vit-D will remain more or less constant. (Yes i know there are many other forms of vitamin D but rarely are they measured except in rare clinical conditions, and many are still up for debate as their exact functions)
As you rightly say even at 150nmol/L you wont do yourself any harm but i suspect its more of less pointless and quite rare outside of heavy supplementation or bolus injections.