Increased intakes of polyphenols may reduce the risk of cardiovascular disease by an impressive 46%, according to the results of the international PREDIMED (Prevencion con Dieta Mediterranea) study.
Data from over 7,000 participants indicated that the highest average intakes of flavanols, which includes compounds such as proanthocyanidins, catechins, and theaflavins, were associated with a 60% reduction in CVD risk, reported researchers in Nutrition, Metabolism and Cardiovascular Diseases .
In addition, the highest average intakes of lignans were aassociated with a 49% reduction in CVD risk.
“Previous studies have demonstrated that polyphenols and their metabolites can reduce blood pressure, as well as markers of oxidation and inflammation,” wrote the authors, led by A.Tresserra-Rimbau from the University of Barcelona in Spain.
“They may prevent or improve endothelial dysfunction, not only by reducing the expression of NADPH oxidase, but also by increasing antioxidant enzyme activity, anti-inflammatory effects, and bioavailability of nitric oxide and by inhibiting low density lipoproteins,”
Consumption of foods that are rich in polyphenolic compounds has long been associated with health benefits related to cardiovascular function, including the modulation of various cardiovascular parameters such as, vascular and platelet function, blood pressure and the plasma lipid profile, with modulation of oxidative stress, inflammation, and endothelial function.
However, according to the PREDIMED researchers, the epidemiologic findings have been inconclusive. They argued that this may be due to a reliance on the USDA (US Department of Agriculture) Flavonoid Database, “which captures only a subgroup of polyphenols (the flavonoids) and therefore do not reflect the wide amount and diversity of polyphenols found in food”, they said.
For their new study, the researchers used the Phenol-Explorer database to evaluate the polyphenol intakes of 7,172 participants of the study, and the potential associations with cardiovascular events, including heart attack, stroke or death from cardiovascular causes.
Over the course of 4.3 years of follow-up, the researchers documented 273 cases of CVD.
Crunching the numbers revealed that the highest overall intakes of polyphenols (an average of 1,170 milligrams per day) were associated with a 46% reduction in the risk of CVD, compared to the lowest overall intakes (an average of 562 mg per day).
In addition, other statistically significant associations were observed for subclasses of polyphenols, including lignans (a 49% reduction associated with the highest average intakes (0.94 mg/d) vs the lowest average intakes (0.44 mg/d)), anthocyanins (a 33% reduction associated with the highest average intakes (11.8 mg/d) vs the lowest average intakes (74.6 mg/d)), and dihydrochalcones (a 37% reduction associated with the highest average intakes (5.8 mg/d) vs the lowest average intakes (0.8 mg/d)).
“We conclude that there is an inverse association between total polyphenol intake and risk of cardiovascular-related events that is independent of other dietary and non-dietary CVD risk factors,” they wrote. “Similar significant associations were established for lignans, flavanols, and hydroxybenzoic acids. Further randomized controlled trials are needed to confirm the promising protective effects of polyphenols on CVD and establish dietary recommendations and desired minimum levels of intake.”
Source: Nutrition, Metabolism and Cardiovascular Diseases
Published online ahead of print, doi: 10.1016/j.numecd.2013.12.014
“Inverse association between habitual polyphenol intake and incidence of cardiovascular events in the PREDIMED study”
Authors: A. Tresserra-Rimbau, E.B. Rimm, A. Medina-Remon, et al. on behalf of the PREDIMED Study Investigators