I have read that vitamin d is one of the most important vitamins.Hmmm, you need more calories, and might, but not necessarily, need more vitamins. But the good thing is that the more calories you consume, generally the more vitamins you consume aswell so it sort of fixes itself. The only vitamin I've ever been deficient in my whole life is vitamin D, and I've been working out and grappling for two decades. Nothing beats going in and getting your own bloods though of course.
