Evidence from dietary intervention trials supports the concept that the intake of polyphenol bioactives can provide beneficial effects in humans. However, the amount of polyphenol ingested in many intervention trials often exceeds the average, habitual dietary intake of these bioactives in most populations. In this context, it is important to investigate whether or not the long-term intake of dietary polyphenols poses risks for human health and wellbeing. While increasing the consumption of fruit and vegetables, i.e. polyphenol-containing foods and beverages would intuitively seem to be safe and even recommended, there’s a paucity of data regarding the potential risks of high-polyphenol diets. Furthermore, safety and toxicity studies of polyphenols in animals are likely of limited use, due to novel insights that indicate significant differences in the spectrum of polyphenol metabolites in humans and rodents. In this context, we aimed at investigating the safety profile of a particular group of dietary polyphenols, the cocoa flavanols (CF), in humans. To accomplish this, healthy middle-aged adults consumed CF at different intake amounts and intake durations, while changes in blood pressure (BP), platelet function, metabolic parameters, liver function and adverse events (AEs) were assessed. The results demonstrate that the daily consumption for 12 weeks of up to 2000 mg of CF did not affect BP, platelet function, liver panels, or metabolic markers. Participants (49 out of 132; 37%) reported AEs during the study, however, the AEs recorded were classified as mild in severity, and none was causally linked to the consumption of CF. Collectively, we show that the consumption of up to 2000 mg of CF daily is well tolerated by healthy adults. However, considering the structural diversity of dietary polyphenols, the extrapolation of information on the overall safety of other polyphenols based on the data provided here should only be undertaken with caution.

Safety of cocoa flavanol intake in healthy adults

253rd National Meeting (2017)

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