Randomized controlled trials for vitamin D should measure baseline levels and quantify outcomes, as levels do not increase linearly with supplementation and can be influenced by sun exposure.

“When you do a randomized controlled trial with a drug, a pharmaceutical, you know, drug, people have zero levels of that in their body to start with. You know, you give them that drug or the placebo, and it's obviously, you know, they're going from zero to something. Whereas, with something like vitamin D, and also with nutrition in general, that you have to measure things at baseline, you have to quantify it. You know, you have to have something quantifiable. And I've seen randomized controlled trials, believe it or not with vitamin D where they don't measure vitamin D levels. They just give them the supplement. And it blows my mind that that can even get past peer review, or how do you design a trial that way?”