Not only is it the Vitamin C that is beneficial, but ...
Lemons and limes contain disease-fighting compounds known as limonoids. The human body is able to readily absorb a specific, long-acting limonoid known as limonin, according to the US Agricultural Research Service. Both lemons and limes contain nearly as much limonin as they do vitamin C. The results of a 2001 culture study summarized in "Nutrition and Cancer," revealed that this compound, at a concentration of 100 mcg/mL, was effective at partially inhibiting the growth of human ovarian cancer cells and inducing the death of breast cancer cells.
I got this info from another blog. It can't hurt to try it. It seems like even if you don't have cancer that this can help you to be healthier.