The new rat study – published in Molecular Nutrition & Food Research – reports to have confirmed, for the first time in an animal model, the potential protection effect that flavonoids in cocoa have against colon cancer onset. The research team, led by María Ángeles Martín Arribas of the Spanish Institute of Food Science and Technology and Nutrition (ICTAN), found consumption of a cocoa rich diet prevents intestinal complaints linked to oxidative stress – including the onset of chemically induced colon cancer.
“Foods like cocoa, which is rich in polyphenols, seem to play an important role in protecting against disease," said Martín Arribas.
“Our findings provide the first in vivo evidence that a cocoa-rich diet may inhibit the early stage of colon carcinogenesis,” wrote the research team – explaining that the likely mechanism for such effects was that the flavanoids in cocoa blocked oxidative stress and cell growth, and possibly caused cell death (apoptosis) in cancer cells.
“Taken together, our data provide evidence that consumption of cocoa would offer a natural therapeutic approach to improve individual health status including potential efficient cancer prevention with minimal toxicity,” said the authors.
The authors noted that there is growing interest amongst the scientific community to identify those foods capable of preventing diseases. They said that some have categorised cocoa as a 'superfood', in recognition of it as an excellent source of phytochemical compounds that may offer health benefits.
The ICTAN scientists fed rats with a cocoa-rich (12%) diet for eight weeks before inducing cancer using the chemical azoxymethane (AOM).
Martín Arribas outlined that four weeks after being administered with AOM, intestinal mucus from cancerous lesions appeared: “These lesions are called 'aberrant crypt foci' and are considered to be good markers of colon cancer pathogenesis," she explained.
The results of the study showed that the rats fed a cocoa-rich diet had a significantly reduced number of aberrant crypts in the colon.
Likewise, the cocoa-rich diet group were found to have an improvement in antioxidant defences and a decrease in the markers of oxidative damage induced by the toxic compound.
Martín Arribas and her team concluded that the protective effects of cocoa blocks cell-signalling pathways involved in cell growth and, therefore, subsequent cancer tumour formation.
Although more research is required to determine what bioactive compounds in cocoa are responsible for such effects, the ICTAN researchers confirmed that a cocoa-rich diet seems capable of reducing induced oxidative stress.
Source: Molecular Nutrition & Food Research
Volume 55, Issue 12, pages 1895–1899, doi: 10.1002/mnfr.201100363
“Cocoa-rich diet prevents azoxymethane-induced colonic preneoplastic lesions in rats by restraining oxidative stress and cell proliferation and inducing apoptosis”
Authors: I. Rodríguez-Ramiro, S. Ramos, E. López-Oliva, A. Agis-Torres, M. Gómez-Juaristi, et al