OK... last post before I get banned for spamming...
I was really hoping that Theranos would live up to its promise and not turn out to be a fraud, because where the real benefits would accrue is if you easily and cheaply obtain an annual blood panel that would measure levels of hundreds of markers and then figure out what's happening your body. Then we could target areas where we are deficient.
Personally, I was suffering from something and thought anemia was one possible cause. Took some iron supplementation and it went away. Kept taking it. A year later, when I had a physical, my iron levels were deemed too high (slightly outside of normal range), which can also have negative health consequences. I bet there would be health benefits from doing this right and supplementing in the case of true deficiency.
BTW - many of the benefits of vitamins are based on epidemiological studies comparing deficient to normal, not comparing normal to supplemented.