So I've been hearing a lot about a new supplement, curcumin. It came up when I saw that biotest, a company whose products I use. It seems as soon as a new supplement comes out, people jump on the bandwagon and start talking about it like it’s the next big thing.
Let’s dare, even just for a minute, to pretend that maybe supplement companies don’t always have our best interests at heart, and maybe taking your money is more important to them than being honest with you. At the very least, lets dare to question the "research" that goes into supplement creation and advertisement—it’s not exactly the same steps that go into drug development in research hospitals (don't get me started on pharmaceuticals, though). With my crazy assumption, lets explore for a minute the bio-chemical process by which curcumin is used in the body, the potential benefits, and the risks.
The possible benefits of curcumin are currently being explored. It has demonstrated chemopreventive properties in both anti-initiating and anti-promoting activities in several experimental systems (1). Please remember that a couple studies does not mean that you can make statements like “curcumin is a powerful chemopreventive agent.” While it helps sell the product, it’s not honest. Instead, you can only state that curcumin has possible chemopreventive effects, and should be further explored. Unfortunately, people normally just believe the former, and go off and take 1000-2000mg of curcumin a day (dose recommended by Biotest). It constantly shocks me that this happens. If I were to tell you to take enormous doses of an NNRTI (Non-nucleoside reverse transcriptase inhibitor) because it has an anti retroviral effect, you wouldn’t go out and do it. If you did, you’d quickly develop significant hepatoxicity and suffer from numerous other side-effects. That being said, just because curcumin is a derivative of a natural product doesn’t mean that it’s somehow only beneficial. Just as is the truth with just about everything, there is also a potential for negative effects.
The National Toxicology Program Study showed that dietary administration of turmeric with a high curcumin content induced clitoral gland adenomas in female rats (2). Also, there is evidence for carcinogenic activity of turmeric (curcumin) in mice based on an increased incidence of hepatocellular adenoma. There is a demonstrated prooxidant property of curcumin with metabolic activation by CYP enzymes (CYP 2D6, 1A1, 1A2, 2E1) (3). The mechanisms of the double-sided (chemopreventive and carcinogenic) properties of curcumin is a byprodect of in-vivo metabolism within the body.
In a metabolic pathway, curcumin converts via hydrogenation to tetrahydrocurcumin, which is the actual promising chemopreventive agent in curcumin (4). At the same time, curcumin is goes through O-demethylation through the CYP enzymes listed above to O-demethyl curcumin (5). O-demethyl curcumin then oxidizes into O-demethyl curcumin radical, leading to an o-quinone form. NAD(P)H reduces the o-quinone form to a catechol form through doble electron reduction (6). This redox reaction results with the production of 02-, which leads to oxidative DNA damage. In this way, the consumption of curcumin, while producing tetrahydrocurcumin, and therefore having a chemopreventive effect, also continually generates reactive oxygen species (free radicals), and cause continuous DNA damage.
The moral of this story is that when it comes to dietary supplements, worry about what you’re eating, and only then look to supplementation. Then, when looking at supplements, ask yourself “am I getting some of this in my diet?” If the answer is no, ask yourself, “would it be easy enough to?” If the answer is yes, go and do that. Don’t jump to taking some micronutrient in pill form just because we’re constantly led to believe that if a little bit is good for a specific population, more will be better for me. If you can’t get something in your diet and you feel that you would benefit from it, talk to a nutritionist. I’ve said it before, but Brian St-Pierre has helped me balance-out my diet on more than one occasion, and I can’t stress enough how much it has helped me. You can check out his latest post (which can somewhat be related to this one) here. In the end, remember that a balance in diet will do more for you than any amount of supplementation. If you’re not winning the fork and knife battle, you’re never going to win the war.
1. Deshpande SS, Ingle AD, and Maru GB. Chemopreventive efficacy of curcumin-free aqueous turmeric extract in 7,12-dimethylbenz[a]anthracene-induced rat mammary tumorigenesis. Cancer Lett123: 35–40, 1998.
2. National Toxicology Program. NTP toxicology and carcinogenesis studies of turmeric oleoresin (CAS No. 8024-37-1) (major component 79%–85% curcumin, CAS No. 458-37-7) in F344/N rats and B6C3F1 mice (Feed Studies). Natl Toxicol Program Tech Rep Ser427: 1–275, 1993.
3. Sakano K and Kawanishi S. Metal-mediated DNA dam-age induced by curcumin in the presence of human cytochrome P450 isozymes. Arch Biochem Biophys 405:223–230, 2002.
4. Okada K, Wangpoengtrakul C, Tanaka T, Toyokuni S, Uchida K, and Osawa T. Curcumin and especially tetrahy-drocurcumin ameliorate oxidative stress-induced renal injury in mice. J Nutr131: 2090–2095, 2001
5. Ireson CR, Jones DJ, Orr S, Coughtrie MW, Boocock DJ, Williams ML, Farmer PB, Steward WP, and Gescher AJ. Metabolism of the cancer chemopreventive agent curcumin in human and rat intestine. Cancer Epidemiol Biomarkers Prev11: 105–111, 2002.
6. Hirakawa K, Oikawa S, Hiraku Y, Hirosawa I, and Kawanishi S. Catechol and hydroquinone have different redox properties responsible for their differential DNA-damaging ability. Chem Res Toxicol15: 76–82, 2002.