This is a sort of continuation of yesterday’s post. In his comment, Peter asked an excellent question…my answer is that he is right, that these studies may not help us in practical terms right now, but they do point to the possibility that there is more to the curcumin picture than its well-documented poor bioavailability (when administered orally). The evidence that there may be other mechanisms at work seems to be accumulating…that is, unless I have completely misunderstood the studies that I have been reading recently!
The 2006 study (abstract: http://tinyurl.com/awyvv9) that I want to discuss today was sent to me recently by a friend (grazie!). It examines the link between the anticancer effects of dietary compounds and ion channels, which are membrane-bound proteins […] that are present on the surface of various cancer cells and tissues. Heh, and I thought cell membranes were difficult!
The activity of these ion channels is essential, it appears, for the progression of cancer…and metastasis. When certain ion channels (VPSCs, or voltage-gated sodium channels) are upregulated while others (VGPCs, or voltage-gated potassium channels…er, don’t ask!) are downregulated, in fact, cancer cell membranes get all excited, in line with such cells’ ‘hyperactive’ behaviour. The activity of ion channels has been found to control/enhance a variety of cellular behaviours that would be involved in the metastatic cascade. Oh boy.
The researchers therefore suggest that ion channels may be a major target for the anti-cancer effects of some natural compounds. By the way, an explanation of ion channels can be found at “Ion channels for beginners”: http://tinyurl.com/cae5b6 (see “Things ion channels do,” in particular). And the term “voltage-gated” is explained here: http://tinyurl.com/2lpqmo
At any rate, the main point is that the researchers set out to see if ion channels could be affected by a few well-known anticancer dietary compounds. What they discovered is significant, since, as I understand matters, when ion channels are affected, the various processes that lead to cancer progression/mestastasis are essentially stopped.
Well, as it turns out, resveratrol affects ion channel activity, thus reducing the excitability of metastatic cancer cells. So does curcumin, even though more evidence is needed for the latter, according to the study. The list of ion channel-affecting substances goes on: capsaicin, genistein, ginseng…ah, also omega 3 PUFAs and zinc. In fact, thanks to this study, genistein moved to the top of my to-be-tested supplement list.
My own ramblings. Okay, we know that very little curcumin ends up in the bloodstream, plus a lot of it gets transformed into metabolites that may not be as powerful as the original stuff (although that is an unresolved question, as we have seen in previous posts)…but just yesterday we learned that curcumin affects cell membranes…and today we find out that curcumin most likely affects ion channels, which are involved in cancer progression and metastasis. Well, the only possible conclusion, in my view, is that curcumin and other poorly bioavailable substances may work in ways that have yet to be explored. And this is all very encouraging to me, an enthusiastic curcumin-taker with smoldering myeloma…