A recent study led by MIT and published in the journal Nature has revealed that fasting followed by refeeding, known as intermittent fasting, can enhance cell regeneration in the intestines, but could also raise the risk of developing intestinal tumors.
Researchers examined the gut stem cells of three groups of mice: a control group that ate normally, a group that fasted for 24 hours, and a group that fasted for 24 hours followed by unlimited feeding for another 24 hours. They observed that stem cell regeneration was reduced during fasting but surged during the refeeding phase.
Study authors Omer Yilmaz, Shinya Imada, and Saleh Khawaled noted that refeeding creates a unique condition that boosts the ability of intestinal stem cells to repair damage to the intestine. While this increased regeneration may help gut cells recover more quickly, the study also indicated that under certain conditions, such as exposure to cancer-causing mutations during the refeeding period, mice were more prone to developing early-stage intestinal tumors
"Having more stem cell activity is good for regeneration, but too much of a good thing over time can have less favorable consequences," said Yilmaz.
The authors cautioned that the effects of fasting in humans are likely more complex than those seen in lab mice, indicating that further research is crucial to understand whether similar changes occur in human gut stem cells.
"But it does lead us to the following notion: Fasting is very healthy, but if you're unlucky and you're refeeding after a fasting, and you get exposed to a mutagen, like a charred steak or something, you might actually be increasing your chances of developing a lesion that can go on to give rise to cancer," states Yilmaz.
He also mentioned that the regenerative advantages of fasting could be beneficial for individuals undergoing radiation treatment or suffering from intestinal injuries and that his lab is exploring whether polyamine supplements could stimulate regeneration without the need for fasting.