Chemopreventive effects of anthocyanins on colorectal and breast cancer: A review

The present review has analyzed the scientific literature, available in the PubMed and Scopus databases, in order to summarize the current state of diet anthocyanin research in breast cancer (BC) and colorectal cancer (CRC) animal models but also for up-to-date human studies. For CRC, 28 preclinical and 9 clinical studies were selected in line with our search query in science databases. In relation to BC, 14 preclinical and 5 clinical studies were selected. Remarkably, all the preclinical studies, to a greater or lesser degree, suggested a chemoprevention effect of anthocyanin in BC/CRC rodent models. These encouraging results from animal models are not extrapolated to the same degree to human studies where, from the similar theoretical daily doses of anthocyanins in these studies, the opposite results were reported. Nevertheless, it is worth mentioning that the anthocyanin doses in the human studies carried out recently are low if we consider the estimated exposure to anthocyanins issued by the European Food Safety Agency (EFSA) or extremely low if we consider with caution the human equivalent dose based on body surface area from the preclinical dosage regimes used. Therefore, although some clinical data has demonstrated an inverse relation between anthocyanin consumption and BC/CRC, this could, in fact, be more relevant if we increase the daily human anthocyanin dose (as observed in animal model dose-effect studies) while new toxicological data for this flavonoid subtype are brought to light.