I have never until now heard of Original Limu and from what I find on the Internet it seems to be more of a multi-level marketing opportunity than a wonder drug. Sales are impressive but I can find NO studies at all for the 1000's that are said to exist.
As for omenga-3, this must be a typo. I think what was meant was Omega-3 which has had studies done on it and is worth looking into.
I would suggust getting a good vitamin book and looking up cancer and/or immune system in the index. You will usually find vit C, vit E, various B vitamins, and supplements such as selenium. All in all, a healthy diet and exercise seem to be the best bet.
God bless, kevin