The curry spice turmeric is always popping up in health news these days and the thousands of studies that have been carried out on it suggest all manner of health benefits (for interesting information see greenmedinfo.com). However most studies have been carried out on isolated constituents (curcuminoids) that are proposed to be the ‘active’ components, therefore seemingly rendering the rest of the plant unnecessary for medicinal benefits. Herbalists, however, believe that a whole medicinal plant is a delicately balanced mix of many thousands of different compounds that all act together in the body to have a beneficial effect and isolating chosen components is not desirable as the extract is then ‘unbalanced’ and prone to causing unwanted side-effects in the body or indeed being less effective. Since virtually all published studies use curcuminoid extracts and there are very few that use the whole plant it is difficult to compare the two when looking at research, however a handful of studies can be found that compare the two and indeed do indicate that whole turmeric is preferable to the curcuminoid extract. The evidence is limited due to the pre-clinical nature of the studies and the high doses administered which are not achievable in clinical practice, although tentative conclusions can be drawn.
Evidence shown is:
- Increased bioavailability of the curcumin in whole turmeric extract (possibly 10 times (Martin et al., 2012))
- Martin et al., 2012 shows no evidence of antiinflammatory effect for oral curcumin in rats, with a possible pro-inflammatory effect, compared to the anti-inflammatory effect of whole turmeric.
- Liu et al., 2008, shows similar in-vitro efficacy of turmeric to curcumin at much lower concentrations of curcumin in the whole extract, at at least 5 times lower concentration, suggesting 5 times the efficacy for whole turmeric compared to isolated curcumin.
- The evidence from Liu et al., 2008 also suggests that as concentrations of curcumin reduces, towards more achievable serum concentrations, the efficacy of the whole extract increases further compared to the isolated curcumin. This suggests that efficacy is not directly proportional to curcumin concentration in the whole plant and the study does not find a minimal ineffective concentration of whole plant curcumin therefore suggesting that the action of the whole plant depends on the natural balance of constituents.
- Samanta et al., 2010, comparing equal weights of whole turmeric and curcumin, find whole oral turmeric and not curcumin effective in reversing histo-pathological changes in rat kidney.
- Chakravarty et al. find ethanolic turmeric extract has immunological effects whereas isolated curcumin has no such effect.
Taken together, all the studies comparing whole turmeric and curcuminoids suggest additional benefits of using the whole turmeric extract and that the curcuminoid content is not as crucial as has been proposed.
In addition, recent studies are also showing other non-curcuminoid compounds such as tumerone having potentially beneficial effects (e.g. on nerve cell health) which further suggests that the whole plant is preferable to isolated constituents
Chakravarty, A. K., Chatterjee, S. N., Yasmin, H. & Mazumder, T. (2009). Comparison of efficacy of turmeric and commercial curcumin in immunological functions and gene regulation. International Journal of Pharmacology,5(6), 333-345.
Liu, D., Schwimer, J., Liu, Z., Woltering, E.A. & Greenway, F.L. (2008). Antiangiogenic effect of curcumin in pure versus in extract forms. Pharmaceutical Biology, 46(10-11), 677-682
Martin, R.C., Aiyer, H.S., Malik, D. & Li Y. (2012). Effect on pro-inflammatory and antioxidant genes and bioavailable distribution of whole turmeric vs curcumin: Similar root but different effects. Food and Chemical Toxicology, 50(2), 227-231. doi: 10.1016/j.fct.2011.10.070.
Samanta, L., Panigrahi, J., Bhanja, S. & Chainy, G.B. (2010). Effect of turmeric and its active principle curcumin on t(3)-induced oxidative stress and hyperplasia in rat kidney: a comparison. Indian Journal of Clinical Biochemistry, 25(4), 393-397.