I've tried substituting olive oil with walnut oil in the past, but that made me vomit. As a matter of fact, I was thinking about taking flax seed oil. I'll give that a try in the near future. I haven't lost my taste for olive oil when it comes to taking it with food, it is just when I take it with the grapefruit juice it turns my stomach.
Thanks for the idea about the straw deh, I'll try that next time.