Curcumin has been much in the news as of late as considerable cell culture data has been suggestive of the compound’s utility in cancer prevention and cancer treatment. The impetus for me speaking on this has been the recent report by my ScienceBlogs.com colleague, Razib, at Gene Expression.
Unfortunately, the story of curcumin has been clouded by overly aggressive attempts by marketers to manipulate in vitro, or Petri dish, cell culture studies with human consumption. Some very outstanding scientists have been working on the anticancer effects of this herb, but it seems that their efforts and results have been overexaggerated and misrepresented.
Briefly, we have known that many natural compounds used at high concentrations, including curcumin, can arrest or kill human cancer cells growing on a plastic dish in the laboratory.
The bigger question in using these remedies for humans with cancer has been whether the concentrations used in cell culture can be acheived in the bloodstream of patients. Most naturally-occuring compounds must be concentrated hundreds or thousands-fold from their natural source, and then be given at doses that would choke a horse.
With curcumin, the very attractive in vitro anticancer data on the compound is offset by the fact that curcumin is poorly bioavailable. What that means is that one takes a certain amount of curcumin by mouth, very little is absorbed into the bloodstream. The question, with curcumin and any other drug, is whether concentrations that kill cancer cells in culture can be achieved in human cells.
Sadly, this is not possible with curcumin, at least at doses of one or more grams per day.
Any recommendations for its use in humans should not be taken seriously until prospective studies of its anticancer action are performed in human subjects.