LA JOLLA, Calif. — Studies have consistently shown that time-restricted eating patterns increase lifespan, which explains why intermittent fasting is all the rave in the dieting world. Despite this, the in-depth molecular and systemic explanation for this has remained unclear. Now, Salk Institute researchers have cracked the code on how intermittent fasting affects gene expression across several regions in the body and brain.
“We found that there is a system-wide, molecular impact of time-restricted eating in mice,” says Professor Satchidananda Panda, the study’s senior author and holder of the Rita and Richard Atkinson Chair at Salk, in a media release. “Our results open the door for looking more closely at how this nutritional intervention activates genes involved in specific diseases, such as cancer.”
To conduct this work, two groups of mice were fed high-calorie diets, but one group could only eat within a nine-hour window. The other had access to food at any time. After seven weeks, the team collected samples from 22 organ groups and the brain throughout different times of the day or night to analyze them for genetic changes. They included a variety of samples from places like the liver, stomach, lungs, heart, adrenal gland, hypothalamus, kidney, and intestines. They ultimately found that 70 percent of the genes responded to time-restricted eating patterns.
“By changing the timing of food, we were able to change the gene expression not just in the gut or in the liver, but also in thousands of genes in the brain,” says Panda.
Intermittent fasting improves genes that prevent disease
Additionally, time-restricted eating affected almost 40 percent of genes within the adrenal gland, hypothalamus, and pancreas — which are all areas important for proper hormone regulation. Maintaining proper hormone balance has consistently been shown to be key in preventing diabetes and stress disorders. Thus, these findings support the notion that time-restricted eating might help manage these conditions better.
Within the digestive system, the diet did not affect every area in the same way. Genes in the upper part of the small intestine were activated by time-restricted eating, but the lower portion was not.
This may pave the way for new research to explore how shift-based jobs disturb our biological clock, or circadian rhythm, and subsequently influence cancers and digestive conditions. Panda and the team have previously conducted work showing that restricting eating times improved health outcomes for firefighters, who generally work unusual and late-night shifts. Based on this most recent study, the team says that restricting eating times successfully aligns circadian rhythm across the body, in multiple organs.
“Circadian rhythms are everywhere in every cell,” Panda concludes. “We found that time-restricted eating synchronized the circadian rhythms to have two major waves: one during fasting, and another just after eating. We suspect this allows the body to coordinate different processes.”
Panda’s team looks ahead to exploring how intermittent fasting affects certain conditions like atherosclerosis, which is a hardening of the arteries that often results in heart disease or chronic kidney disease.
The findings appear in the journal Cell Metabolism.