I don't think it matters unless your investments are limited. If you have presented with X positive expected value investments, and you have enough funds for X+1 investments, what do you do? Invest in all X and reap the maximum possible return. (If you are limited to only 2 investments, then you will be very interested in which 2 investments of the X investments have the greatest sized expected value.)

This is pretty much the case with supplements: I don't lack capital to invest in them (look at how cheap some of the examples are, like lithium or melatonin), I lack good candidates for investment!