Cells sub-issue: Salk scientists show changes in gene expression throughout the body induced by time-restricted eating

Numerous studies have shown the health benefits of time-restricted diets, including extending life expectancy in laboratory studies and making practices such as intermittent fasting a hot topic
in the health industry.
However, exactly how it affects the body at the molecular level and how these changes interact in multiple organ systems is not well understood
.
Now, in mice, Salk's scientists have shown how time-restricted eating affects gene expression
in more than 22 regions of the body and brain.
Gene expression is the process by which genes are activated and respond to the environment by
creating proteins.

The findings, published in Cell Metabolism on January 3, 2023, have implications for a variety of health conditions, including diabetes, heart disease, high blood pressure, and cancer
.

Professor Satchidananda Panda, senior author and chair of Professor Rita and Richard Atkinson at Salk University, said: "We found that in mice, time-restricted eating has an effect
on the whole system and molecule.
Our findings open the door
to a closer look at how this nutritional intervention activates genes associated with specific diseases, such as cancer.
”

In this study, both groups of mice were fed the same high-calorie diet
.
One of the groups gets food
for free.
The other group was restricted to eating
for 9 hours a day.
After seven weeks, the researchers collected tissue samples from 22 organ groups and brains at different times of the day or night, and analyzed the genetic changes
.
The sample includes tissues
from different parts of the liver, stomach, lungs, heart, adrenal glands, hypothalamus, kidneys, and intestines, as well as different areas of the brain.

The authors found that 70 percent of the mouse genes responded to
time-restricted eating.

"By changing the timing of eating, we can change gene expression not only in the gut or liver, but also in the brain
," Panda said.

Nearly 40% of genes in the adrenal glands, hypothalamus, and pancreas are affected
by time-restricted diets.
These organs are important
for hormonal regulation.
Hormones coordinate the functioning of different parts of the body and brain, and hormonal imbalances have been linked to
many diseases, from diabetes to stress disorders.
The findings provide guidance
on how time-restricted diets can help control these diseases.

Interestingly, not all parts of the digestive tract are affected
equally.
In the case of time-restricted eating, genes in the upper part of the small intestine (duodenum and jejunum) are activated, while the ileum located at the lower end of the small intestine does not
.
The discovery could open up a new line of research into how shift work affects digestive diseases and cancer
.
Shift work disrupts our 24-hour biological clock, known as circadian
rhythms.
Previous research by Panda's team has shown that restricting eating times can improve the health of firefighters, who are typically shift workers
.

The researchers also found that time-restricted diets coincided
with circadian rhythms in multiple organs of the body.

"Circadian rhythms are ubiquitous in every cell," Panda said
.
"We found that time-restricted eating synchronizes circadian rhythms, producing two waves: one during fasting and the other after
eating.
We suspect that this allows the body to coordinate different processes
.
”

Next, Panda's team will take a closer look at the effects of time-restricted eating on specific conditions or systems involved in the study, such as atherosclerosis, a type of arteriosclerosis that is often a precursor to heart disease and stroke, and chronic kidney disease
.