Indians are no strangers to
fasting. It is a cultural experience at this point, with various religions incorporating it in different ways — think the Paryushan Parva observed by Jains,
Karva Chauth practised by Hindus and Ramdan among Muslims. However, more and more people are gaining awareness about the
health benefits of the act of fasting, with research suggesting it can delay certain diseases and potentially extend lifespan.
But as is the case with most things, the effects of fasting are not all black or white.
For instance, a recent
Nature study conducted on mice uncovered that the real health
benefits of fasting may emerge not during the fast itself, but when one breaks the fast and resumes eating. This refeeding period, according to the study, triggers a surge in stem cell activity that helps repair damage in the intestines.
Ömer Yilmaz and his team at the Massachusetts Institute of Technology (
MIT) revealed that
stem cells in the intestines multiplied at the highest rate when mice were allowed to eat again after a 24-hour fast. These stem cells are crucial for repairing and regenerating the intestinal lining, thanks to the production of molecules known as polyamines, which are essential for cell growth and division. Yilmaz points out that while the emphasis has often been on the duration of fasting, the refeeding phase is equally important and warrants closer attention.
However, this
regenerative process comes with a concerning downside: an increased risk of developing
precancerous polyps if a cancer-causing genetic change occurs during this vulnerable time.
The same stem cells that aid in tissue repair are also prone to becoming precancerous if a cancerous gene is activated during the refeeding period. This finding raises concerns about the potential
risks of fasting, particularly in individuals who may be genetically predisposed to cancer. Since the study was conducted on mice, researchers like Yilmaz are planning clinical trials for humans to understand their implications on our bodies.
Valter Longo, a biogerontologist at the University of Southern California, suggests that while the study highlights a potential risk, it may not apply broadly, especially considering previous research showing that fasting can reduce abnormal cell growth. Nonetheless, the findings underscore the complexity of fasting and refeeding, suggesting that more research is needed to fully understand the balance between the benefits of cellular regeneration and the risks of
cancer development.
