It certainly has seemed to me that the important part of meditation is the relaxation that it lets you achieve. I think it's literally impossible for me (at least) to get as relaxed as I am after a typical hour of meditation by any nonmeditative means. (If you interpret "relaxation" as having low blood levels of e.g. cortisol this is actually measurable.) And I know that I have days when I don't sufficiently relax myself when I sit, and I usually don't see the same benefits that I do from "good" sits. 'Course, a lot of this could be confirmation bias.
Also, anecdotally, I maintain substantial concentration for 30+ minutes a day because that's what studying is, and the short- and long-term effects of that concentration don't seem to be anything like the effects of meditation.
Myself included.
Point being is that how we react to our environment has a profound affect on the expression (or suppression) of genes in our DNA, and can be passed on through generations.
Mindful meditation is probably (pure conjecture on my part) causing methylation of genes involved in the production of cortisol (indirect).
This of course is nowhere near proof, but it's my experience:
1. After the intense concentration I nearly feel out of it afterwards, or lower in energy. It feels like I have lost track of where and who in the universe I just was. Depending on the task, I may afterwards feel a certain sense of accomplishment or the opposite, wasteful.
2. After an awareness exercise I get a sense of relief. I feel like I can look upon the world in a less biased way -- see reality for more of what it is. I feel like certain worries and stresses have dissipated, and an overall life-focus has improved -- I can see better than usual what is more important for me and for my life. In addition, my judgments of people and things has dissipated too, become more healthy and realistic.
I completely agree a real study would be great though.