Lower CRP levels associated with curcuminoid supplementation in meta-analysis
Friday, August 16, 2013. The results of a meta-analysis described online on August 7, 2013 in the journal Phytotherapy Research reveal a reduction in C-reactive protein (CRP, a marker of inflammation) in clinical trials that compared the effects of curcuminoids to those of a placebo. Curcuminoids are polyphenolic compounds that include curcumin, demethoxycurcumin and bisdemethoxycurcumin, which occur in the spice turmeric. The compounds are known to have an anti-inflammatory effect as well as other benefits.
For the meta-analysis, Amirhossein Sahebkar of Mashhad University of Medical Sciences in Iran selected six trials that included a total of 172 subjects who received curcuminoids and 170 who received placebos for periods ranging from six days to three months. The analysis concluded that C-reactive protein values were lower by 6.44 milligrams per liter (mg/L) among participants who received curcuminoids in comparison with those who received a placebo. (Less than 10 mg/L is considered a normal CRP level; however, an optimal range is less than 1.0 mg/L in women and below 0.55 mg/L in men.) Significant effects were observed in studies involving at least four weeks of treatment duration with curcumin supplements that featured improved bioavailability.
Mechanisms involved in cucurminoids' ability to lower CRP include suppression of the nuclear factor kappa B pathway involved in the production of proinflammatory cytokines as well as an ability to reduce the expression and/or release of proinflammatory cytokines via interaction with other signaling pathways, transcription factors and receptors. "It remains to be elucidated by prospective trials if addition of curcuminoids to statins, as the most widely prescribed drug class in cardiovascular disease patients and currently the best known type of CRP-lowering agents, leads to a significantly greater reduction in CRP levels and incidence of primary and secondary CVD events," Dr Sahebkar writes.
"Supplementation with curcuminoids may reduce circulating CRP levels," he concludes. "This effect appears to depend on the bioavailability of curcuminoids preparations and also duration of supplementation. Future well-designed and long-term trials are warranted to verify this effect of curcuminoids."