Foods rich in antioxidants like black tea, the chocolate They can increase the risk of certain types of cancer. This is suggested by a study published today in “Nature” that has analyzed a puzzling fact: why cancer in the small intestine is quite rare, while colorectal cancer, a neighboring organ, although much smaller, is one of the main causes of cancer death in men and women? ¿What does the colon have that seems to ‘attract’ cancer?
The group of Yinon Ben-Neriah and Eliran Kadosh, from the Lautenberg Center for Research on Immunology and Cancer at the Hebrew University of Jerusalem (USA), have discovered that cancer mutations are not necessarily bad actors in themselves . In fact, in certain microenvironments like the gut, these mutations can help the body fight cancer, not spread it.
However, if the gut microbiome produces high levels of metabolites, such as those found in certain bacteria and antioxidant-rich foods like black tea and hot cocoa, then it acts as a particularly hospitable environment for mutated genes and will accelerate growth. of intestinal cancers ..
Researchers may have found the reason why only 2% of cancers develop in the small intestine, while 98% of cancers occur in the colon.
An important difference between these two organs, they explain in their work, is their level of intestinal bacteria: the small intestine contains few, while the colon contains multitudes. “Scientists are beginning to pay increasing attention to the role that microbiomes play intestinal in our health: both its positive effects and, in this case, its sometimes pernicious role in helping and stimulating the disease ”, reveals Ben-Neriah.
TP53 is a gene found in every cell. It produces a protein called p53 that acts as a cell barrier and suppresses genetic mutations in the cell. However, when p53 is damaged, it no longer protects the cell. On the contrary, it drives cancer and helps tumors spread and grow.
To test their theory that gut flora was at stake, the researchers introduced mutated p53 proteins (which promotes cancer) in the intestine. [Todas las células contienen el gen TP53, que produce una proteína llamada p53 que actúa como barrera celular y suprime las mutaciones genéticas en la célula. Sin embargo, cuando p53 se daña, ya no protege la célula. Todo lo contrario, impulsa el cáncer y ayuda a que los tumores se propaguen y crezcan].
Surprisingly, the scientists saw that the small intestine reacted by converting the mutated p53 cancer driver back to normal p53, becoming ‘super suppressors’, more capable of suppressing cancer growth than healthy p53 proteins. But when mutated p53 was introduced into the colon, no such change occurred, but remained true to its cancer-promoting nature and began tumor spread.
“The intestinal bacteria had a Jekyll and Hyde effect on mutated p53 proteins – Ben-Neriah points out. In the small intestine they completely changed their function and attacked cancer cells, while in the colon they promoted tumor growth. “
To test their theory that gut flora was a major factor in why mutated p53 acted as a tumor blocker in the small intestine, but as an accelerator in the colon, the scientists administered antibiotics to clear the gut flora of the colon. Once they did, the mutated p53 was unable to continue its cancer promotion.
So what’s in this flora that makes colon cancer spread so fast? The scientists wondered.
A detailed analysis identified the culprit: the intestinal flora that produces metabolites, also known as ‘antioxidants’, found in high concentrations in foods such as tea black, hot chocolate or nuts.
And, when the scientists fed the mice a diet rich in antioxidants, their gut flora accelerated the cancer-promoting mode of p53. This finding is of particular concern for those patients with a family history of colorectal cancer.
“Scientifically speaking, this is new territory,” says Ben-Neriah. We were surprised to see to what extent microbiomes affect cancer mutations, in some cases, completely changing their nature. ”
Looking ahead, people at high risk for colorectal cancer may want to examine their gut flora more often and think twice about the foods they digest, especially those rich in antioxidants.