black tea, chocolate, and berries may increase risk for cancers

https://medicalxpress.com/news/2020-07-antioxidant-rich-foods-black-tea-chocolate.amp

if the gut microbiome produces high levels of metabolites, like those found in certain bacteria and antioxidant-rich foods like black tea and hot cocoa, then it acts as a particularly hospitable environment to mutated genes and will accelerate the growth of bowel cancers. 

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 A close analysis identified the culprit: gut flora that produces metabolites, aka "antioxidants", which are found in high concentrations in foods such as black tea, hot chocolate, nuts and berries. Tellingly, when the scientists fed mice an antioxidant-rich diet, their gut flora accelerated p53's cancer-driver mode. This finding is of particular concern to those patients with a family history of colorectal cancer.

 

also reported in

 https://www.genengnews.com/news/antioxidants-gone-bad-when-the-microbiome-promotes-cancer/