- A new study has found that time-restricted feeding (TRF) can affect the gene activity of mice.
- Throughout the body, 22 different types of tissues were affected.
- Time-restricted eating (TRE) has been found to have numerous positive benefits on human health.
- The researchers’ findings could potentially help guide therapeutic TRE in humans.
Altogether the effects were exhibited in 22 different tissue types throughout the body, including the heart, lungs, liver, brain, and gut.
“Nearly 80% of all genes show differential expression or rhythmicity under TRF in at least one tissue,” according to the study authors.
They suggest that future work could guide the use of TRE to treat various disease conditions in humans.
Shereen Jegtvig, a nutritionist and author who teaches at the University of Bridgeport in Connecticut, explained that time-restricted eating is a common form of intermittent fasting (IF), which involves eating only during specific hours of the day and fasting for the rest of the time.
“Other forms of IF are more difficult and include fasting for a full day now and then or restricting calorie intake to about 500 or so every other day,” said Jegtvig.
Lead author of the study, Satchidananda Panda, PhD, who holds the Rita and Richard Atkinson Chair at the Salk Institute for Biological Studies in La Jolla, CA, described TRE as limiting calorie intake to a specific, regular period of time each day, leaving a 12- to 18-hour window when no nutrients are consumed.
Panda further noted, “There is no explicit limit on energy intake during eating hours. TRE allows water consumption outside of the designated eating window, but in some cases, non-caloric beverages such as unsweetened tea or black coffee are permitted.”
He additionally suggested that the fasting window should be customized to the individual based on their sleep time and schedule.
Panda added that since the fasting community often uses the terms “intermittent fasting” or “IF” to refer to regimens other than time-restricted eating, TRE (or TRF for animal studies) is the most accurate term to use. [M]ost scientific studies use this term, and curious minds can search this term to find peer-reviewed scientific publications.”
Panda said that while previous research had focused on linking TRF/TRE to a fairly small number of genes in the liver, their study greatly expanded on this work by looking at 22 different organs and brain regions, as well as all genes in the genome.
To do this, Panda and his team allowed a control group of mice to eat as much as they desired while another group was only allowed to consume food during a 9-hour feeding window.
All mice were fed a diet corresponding to a Western diet in humans, and all were supplied with the same number of calories.
At the 7-week mark, the researchers took samples from the designated organs and brain regions of the mice every 2 hours extended over a 24-hour period.
What they found was that, compared with the controls, the TRF mice experienced genomic responses in nearly all tissues and brain regions.
“These changes indicate TRF improves autophagy, mitochondria function, DNA damage repair, proteostasis, RNA folding, fatty acid oxidation, glycolysis, gluconeogenesis, and many more,” said Panda. “These pathways also predict TRF may benefit by reducing the risk for atherosclerosis, kidney disease, dysbiosis, and various gut diseases.”
Panda noted that TRE/TRF has previously been shown to have multiple potential benefits for human health.
“[It] has been shown to prevent, better manage, or in some cases reverse several health conditions,” Panda said.
That list includes but is not limited to conditions such as:
- glucose intolerance
- insulin resistance
- fatty liver disease
- chronic inflammation
- sleep disorders
- age-dependent declines in cardiac function
Jegtvig added that time-restricted eating can also help with weight loss because it reduces the amount of time that you can eat.
“It may also affect insulin and appetite hormone levels, but most of the effect is probably from reducing calories even though counting calories isn’t necessary,” she said.
Jegtvig further noted that small studies suggest it may improve the risk factors for metabolic syndrome and heart disease, although this may be a side effect of the weight loss itself rather than something specific about TRE.
Jegtvig concluded by advising that if you are going to practice TRE or any other form of IF, the feeding window shouldn’t be seen as an opportunity to indulge in unhealthy food.
“While there should be a place for occasional snacks and treats in your diet, it’s important to nourish yourself with healthy foods,” she said.