I think the problem is more simple. People take too much vitamin d. Reading the experiments, I concluded that the ideal blood level is 32 ng/ml, but people want to take supplements to get to 50 ng/ml.
A lot of the Covid prevention websites say to take between 3000 to 5000 mgs a day. I take only 1000 because that is a safe level. When I was tasked by my doctor to take 5000 I was getting migrane headaches all the time. Now I don’t.
vitamin d levels of 50-90 mg ml are considered to be optimal.
Mine are about 68. I take about 10iu of vitamin d3 daily with vitamin k2.
the guy in this study was taking 50k iu vitamin d3 daily which is out of bounds most of the time for most people.
the whole issue with vitamin d3 these days has to do with too few people spending any time at all in the sun on a daily basis. this dead serious because people are not designed to live like bats out of the sun. we need the sun to make vitamin d3, melatonin and nitric oxide in quantity.