NEW YORK (Reuters Health) – A long-term dietary intervention with grape resveratrol supplements improves the inflammatory and fibrinolytic status of patients at high risk of cardiovascular (CVD) disease, Spanish researchers report in an April 19th on-line paper in the American Journal of Cardiology.
The reason for use of a supplement, Dr. Juan Carlos Espín told Reuters Health by email, is that “the presence of resveratrol in the diet is almost negligible. Its content in grape and red wine is low and highly variable. Therefore, the consumption of wine does not ensure the intake of enough resveratrol to exert beneficial effects.”
In fact, even its beneficial effects have been called into question particularly in light of recent revelations about data fabrication (see Reuters Health report 2012-01-11).
Nevertheless, Dr. Espín went on to say that “The vast majority of preclinical research in animal models used very high (pharmacological) resveratrol doses and short-term exposures. This has yielded a huge output of conclusions regarding benefits and mechanisms. This is the easy way: to assay high concentrations in severely injured animals to observe significant results and in a short time.” However, these and other experimental approaches “prevent a direct extrapolation to human health.”
In the current trial, Dr. Espín of CEBAS-CSIC, Murcia and colleagues studied 75 patients all of whom were taking statins and were considered to be at high CVD risk. They had diabetes mellitus or hypercholesterolemia and another CVD risk factor such as arterial hypertension or current smoking.
They were randomized to receive capsules containing a grape supplement with resveratrol 8 mg, a conventional grape supplement lacking resveratrol or placebo. They consumed one capsule per day for 6 months and then went on to 2 capsules per day for a further 6 months.
In contrast to placebo and the conventional grape supplement, the resveratrol-rich grape supplement significantly decreased high-sensitivity C-reactive protein (hs-CRP) by 26%. Despite some controversies, say the investigators, “hs-CRP has emerged as a leading biomarker of inflammation for clinical application and stratification of CVD risk.” This decrease, they add, “could be clinically relevant.”
There was also a reduction in tumor necrosis factor (TNF) alpha (19.8%), plasminogen activator inhibitor (PAI) type 1 (16.8%) and the interleukin-6/interleukin-10 ratio (24%). Supplementation increased interleukin-10 by 19.8%. Adiponectin tended to increase and soluble intercellular adhesion molecule-1 tended to decrease.
The hs-CRP decrease, the researchers point out “was well correlated with the decrease of the proinflammatory cytokine TNF-alpha and thrombogenic PAI-1.” In addition, there were no adverse effects.
Until now, continued Dr. Espín, “there were no long-term studies regarding the role of this molecule, as a dietary compound, in the daily life of people.” Nevertheless “high concentrations of resveratrol are consumed by people worldwide. This is crazy.”
More research is needed, he concluded, but “we have covered the existing gap with this trial.” This shows “grape resveratrol as a safe, dietary-preventive compound with no drug interactions and decreasing cardiovascular risk factors.”