Investigators from the University of Southern California (USC) have found evidence that a low-calorie fasting-mimicking diet has the potential to reduce inflammation and increase intestinal stem cells. The study, published in Cell Reports
, examined the health benefits of periodic cycles of a fasting diet for people with inflammation. There was also evidence that the diet reversed inflammatory bowel disease (IBD) pathology in mice.
In the study, 1 group of mice were given a 4-day fasting-mimicking diet, in which they consumed approximately 50% of their normal caloric intake on the first day and 10% of their normal caloric intake from days 2 to 4. Another group fasted on a water-only diet for 48 hours.
The study found that 2 cycles of a 4-day fasting-mimicking diet followed by a normal diet appeared to be enough to alleviate some, and reverse other, IBD-associated pathologies or symptoms. The water-only diet did not accomplish the same changes, indicating that certain nutrients in the fasting diet contribute to the microbial and anti-inflammatory changes necessary to maximize the effects of the fasting regimen, according to the study.
The investigators had conducted earlier trials, in which they allowed participants to consume between 750 and 1100 calories per day over a 5-day period with a diet that contained specific proportions of proteins, fats, and carbohydrates. Participants of those trials saw reduced risk factors for many life-threatening diseases, the study authors found.
According to the press release
, by promoting the expansion of beneficial gut microbiota, the fast-mimicking diet reduces intestinal inflammation and increases intestinal stem cells. The regimen may also have the potential to mitigate IBD as evidenced by the reversal of IBD pathology in mice and anti-inflammatory effects in the human clinical trial.
The research team observed activation of stem cells and a regenerative effort in the colon and the small intestine, which increased significantly in length only in the presence of multiple cycles of the fasting-mimicking diet. They concluded that fasting primes the body for improvement, but it is the re-feeding that provides the opportunity to rebuild cell tissues.
"This study for the first time combines two worlds of research," said Valter Longo, a study author. "The first is about what you should eat every day, and many studies point to a diet rich in vegetables, nuts and olive oil. The second is fasting and its effects on inflammation, regeneration and aging."
In the current and previous studies, the authors showed that in patients with elevated C-reactive protein (CRP), a marker for inflammation, fasting-mimicking diet cycles are able to reduce CRP and reverse the associated increase in white blood cells. Together with the results in mice, these data indicate that fasting-mimicking diet cycles have the potential to be effective against human IBD, including Crohn disease and ulcerative colitis.
IBD afflicts an estimated 1.6 million Americans and is associated with acute and chronic inflammation of the intestine. The study authors said that a randomized clinical trial involving the use of fasting-mimicking diet cycles to treat IBD is necessary to determine the safety and efficacy of these dietary treatments in humans and are currently finalizing a clinical trial protocol.
Longo is the founder of and has an ownership interest in L-Nutra, whose food products are used in studies of the fasting-mimicking diet. Longo's interest in L-Nutra was disclosed and managed per USC's conflicts-of-interest policies. USC has an ownership interest in L-Nutra and the potential to receive royalty payments from L-Nutra. USC's financial interest in the company has been disclosed and managed under USC's institutional conflict of interest policies.