The trial, claimed to be “the longest human trial reported thus far using a resveratrol-containing product”, found that levels of C-reactive protein (CRP), a well-established marker of inflammation, fell by 26%, report researchers in the The American Journal of Cardiology .
The study was performed in people at high risk of cardiovascular disease (CVD) and the participants were also receiving statins. However, people in the placebo group did not exhibit the same beneficial reductions in inflammatory markers.
“We describe for the first time that a dietary intervention with a specific grape nutraceutical containing resveratrol 8 mg significantly improved the inflammatory and fibrinolytic status of patients undergoing primary prevention of CVD,” wrote researchers, led by Juan Carlos Espin, PhD, from the Research Group on Quality, Safety, and Bioactivity of Plant Foods, CEBAS-CSIC, Murcia.
Heart benefits
Resveratrol, a powerful polyphenol and anti-fungal chemical, is often touted as the bioactive compound in grapes and red wine, and has particularly been associated with the so-called 'French Paradox'. The phrase, coined in 1992 by Dr Serge Renaud from Bordeaux University, describes the low incidence of heart disease and obesity among the French, despite their relatively high-fat diet and levels of wine consumption.
Other studies with only resveratrol have reported anti-cancer effects, anti-inflammatory effects, cardiovascular benefits, anti-diabetes potential, energy endurance enhancement, and protection against Alzheimer’s.
Study details
The Spanish researchers recruited 75 people receiving statins as primary prevention of CVD to participate in their triple-blinded, randomized, parallel, dose-response, placebo-controlled, follow-up trial.
Participants received either a resveratrol-rich grape supplement (resveratrol 8 mg), a conventional resveratrol-free grape supplement resveratrol, or placebo (maltodextrin) for six months, and then double the dose for the next six months.
Results showed a significant decrease in CRP levels in the resveratrol-rich grape supplement only, with no changes in the other two groups. In addition, other markers of inflammation decreased, including tumor necrosis factor-alpha (TNF-alpha, 19.8% decrease), and plasminogen activator inhibitor type 1 (PAI-1, 16.8% decrease).
On the other hand, the resveratrol-rich grape supplement also increased levels of the anti-inflammatory interleukin-10 by 20%, while no such changes were observed in the other groups.
Inflammation and heart disease
“In the present trial, the decrease of CRP in group [resveratrol-rich grape supplement] was correlated with decreases in TNF-alpha and PAI-1 values, which are also important markers in the onset of [cardiovascular] events,” wrote the researchers.
“This is consistent with the known regulation of CRP by many inflammatory signals such as TNF-alpha, which alters vascular endothelium homeostasis, impairs fibrinolytic status by increasing PAI-1 levels, and induces plaque destabilization.”
“Despite the beneficial effects observed, the sample size and follow-up (1 year) prevented conclusions related to prediction of future CV events in these patients,” they concluded.
