vitamins tested, both at baseline and at intervention, or just give the subjects the pills and image the arteries? I'm guessing the latter, as is almost always done. And we call this "science"....
It isn't that hard to test people's blood, and yet the researchers prefer us to take it on faith that their sorting of control and intervention groups ironed all of this out? If I sound unreasonable, I don't apologize for it: public health decisions are important.
Blood tests would tell us if the randomization ended with the two groups being very different, but the prior probability of that is small. Blood tests would also tell us if there is some subgroup that benefits more from the treatment, but with an increased risk of getting the answer wrong due to smaller sample sizes, which would lead to worse public health decisions.