Dietary flavonoid intake and the risk of digestive tract cancers: a systematic review and meta-analysis

Abstract

Several epidemiological studies have investigated the association between dietary flavonoid intake and digestive tract cancers risk; however, the results remain inconclusive. The aim of our study was to evaluate this association. PubMed and the Web of Knowledge were searched for relevant publications from inception to October 2015. The risk ratio (RR) or odds ratio (OR) with the 95% confidence interval (95% CI) for the highest versus the lowest categories of flavonoid intake were pooled using a fixed-effects model. A total of 15 articles reporting 23 studies were selected for the meta-analysis. In a comparison of the highest versus the lowest categories of dietary flavonoid intake, we found no significant association between flavonoid intake and oesophageal cancer (OR = 0.91, 95% CI = 0.75–1.10; I2 = 0.0%), colorectal cancer (OR = 1.02, 95% CI = 0.92–1.14, I2 = 36.2%) or gastric cancer (OR = 0.88; 95% CI = 0.74–1.04, I2 = 63.6%). The subgroup analysis indicated an association between higher flavonoid intake and a decreased risk of gastric cancer in the European population (OR = 0.78, 95% CI = 0.62–0.97). In conclusion, the results of this meta-analysis do not strongly support an association between dietary flavonoid intake and oesophageal or colorectal cancer. Furthermore, the subgroup analysis suggested an association between higher dietary flavonoid intake and decreased gastric cancer risk in European population.

Association between Polyphenol Intake and Breast Cancer Risk by Menopausal and Hormone Receptor Status

“…This is the first study to carry out an analysis including all polyphenol classes and subclasses by menopausal and receptor status. Several reviews [2][3][4][5] summarized the existing evidence about the association between cancer risk and polyphenol intake [53][54][55], suggesting many potential beneficial effects. Flavonoids are the most studied polyphenol class, while other polyphenol classes and compounds, which are also widely consumed by the European population [56], have been rarely investigated.…”

Food-Derived Compounds Apigenin and Luteolin Modulate mRNA Splicing of Introns with Weak Splice Sites

“…For example, polyphenols and carotenoids have antioxidant activity and function in preventing lifestyle-related diseases (Pandey and Rizvi, 2009;Reinisalo et al, 2015;Young and Lowe, 2001). Flavonoids, which are abundant in fruit and vegetables, have been reported to reduce the risk of lifestyle-related diseases and carcinogenesis (Bo et al, 2016;Ló pez-lá zaro, 2009). Despite the broad bioactivity of flavonoids, few studies on their regulatory activity against mRNA processing, especially splicing, have been reported.…”

“…Nonetheless, further evaluation of these flavonoids as anti-cancer drugs should be conducted. On the other hand, it has been reported that xenograft progression of human tumors was repressed by the oral administration of apigenin or luteolin into nude mice (Li et al, 2018;Shukla et al, 2015;Xu et al, 2018) and that the daily intake of bulk flavonoids reduced carcinogenesis in humans (Bo et al, 2016;López-lá zaro, 2009). These findings suggest a beneficial effect of these compounds on preventing cancer development when they are consumed in food on a daily basis for a considerable period.…”

Dietary natural flavonoids treating cancer by targeting aryl hydrocarbon receptor

“…The half-life of flavonoids in the human body is relatively short and dietary exposure to these compounds should be regular so that plasma concentrations are maintained at levels sufficient to express certain biological activities (Zabela et al 2016). In addition, flavonoids undergo extensive metabolic biotransformation in the intestine and liver, which mean that different conjugates circulate in the body with probably substantially altered biological activities and only traces of the parent flavonoids can enter the bloodstream (Bo et al 2016). In addition, considering that flavonoids are mainly present in food in the form of glycosides (Popova and Hincha 2016), the absorption of flavonoids from the diet was believed negligible.…”