A new study has found that mice fed with a high-fat, low-carbohydrate diet, commonly known as a ketogenic diet, accumulated high levels of ageing cells in their organs. A ketogenic diet is popular among influencers, athletes, and people who want to lose weight and improve their metabolism. Published in the journal Science Advances, the study titled Ketogenic diet induces p53-dependent cellular senescence in multiple organs,” revealed that the ketogenic diet puts increased stress on the heart, kidneys, brain, and liver.
However, the accumulation of ageing cells, referred to as cellular senescence, was reversed in mice that took regular breaks from the diet. Independent experts who commented on the research findings argued that the results did not prove that ketogenic diets were harmful to people. One of them, a cardiologist at Cleveland Clinic, Wilson Tang, noted “the “results don’t prove that ketogenic diets are harmful in people. This paper is an important addition. We need to be more cautious and less cavalier.”
According to Science Advances, the rationale behind ketogenic diets is that reducing carbohydrate consumption allows the body to burn fat instead. During this process, the liver produces molecules called ketones, hence the diet’s name.
The diet, originally devised in the 1920s by a doctor at the Mayo Clinic to treat epilepsy in children, has been embraced by individuals seeking to lose weight, reduce blood sugar, boost athletic performance or gain other benefits.
A radiation oncologist at the University of Texas Health Science Centre, San Antonio, David Gius, probed the diet’s effects on p53, a potent cancer-fighting protein. One of the p53 roles is to orchestrate cellular senescence, where stressed cells stop dividing before they cause problems; the immune system usually culls senescent cells. A cellular senescence expert at Imperial College London who was not involved in the new research, Jesús Gil, explained that when senescent cells persist, they can hinder the tissues’ ability to make repairs and exude molecules that can trigger inflammation and other harmful effects.
The journal further states, “Gius and his team stumbled on the senescence connection when they put mice on a supercharged ketogenic diet in which about 90 per cent of the calories came from fat, mainly in the form of the shortening Crisco. A control group of rodents dined on food in which fat provided only 17% of the calories. After the mice stayed on these diets for 7 or 21 days, the researchers analyzed tissue samples from their hearts, kidneys, livers, and brains. “Levels of the p53 protein climbed in animals on the ketogenic diet, the team found. The scientists also detected an increase in other molecules that indicate the presence of senescent cells.”
The researchers further found out that after a three-week pause of the diet, the level of senescent cells had almost returned to normal. The study also revealed that when the mice were placed on a high-fat diet for four days and then allowed to eat normal food for seven days, senescent cells did not accumulate. Gil expressed surprise that the senescent cells disappeared when the mice returned to a normal diet, suggesting that the cells might not have been truly senescent but rather in a similar, reversible inactive state.
A cell biologist at Mayo Clinic, Yi Zhu, explained that senescent cells do not always mean tissue is unhealthy as they also help wounds heal. Zhu added, “Before anyone could claim keto diets are dangerous, researchers would need to demonstrate that the cells harm the mice. Only showing an increase in senescence is not enough to show that the diet is detrimental.” Also, an obesity researcher and statistician at Indiana University, David Allison, noted that the new study finds an effect “for this (one) diet that happens to be ketogenic. That doesn’t mean it’s true for all ketogenic diets.” Although the effects haven’t been replicated in humans, Gius stated that the results may offer a lesson for people following keto regimens. “We aren’t saying the diet is bad. You probably need to take a break,” he advised
