- A new study in mice found that a ketogenic diet did not accelerate the aging of females, although it did cause males to age more rapidly.
- The authors of the study found that the presence of estrogen in the female mice blocked the aging effect of the diet.
- When males were treated with estrogen, estradiol, and antioxidants, the rapid-aging effects of the diets decreased.
- Further study is required to determine if these effects translate to humans.
The popular ketogenic, or keto, diet may accelerate the aging process, suggest studies in animals. According to a new murine, or mouse, study, this effect of the diet is primarily restricted to males.
The study suggests that estrogen protects female mice consuming a keto diet from the risk of accelerated aging.
The authors of the study say the keto diet produces excess oxidative stress, which speeds up cellular aging through the production of senescent cells. They found that treating the male mice in their study with estrogen or estradiol and antioxidant agents eliminated this rapid cell aging.
The study is published in
“The keto diet is a very low-carbohydrate, high fat way of eating that shifts the body’s primary energy source from carbohydrates to fat. Under normal conditions, carbohydrates are the body’s preferred fuel, especially for the brain,” explained Michelle Routhenstein, MS, RD, CDCES, CDN, preventive cardiology dietitian at EntirelyNourished.com.
When the body lacks the carbohydrates it normally uses for fuel, it breaks down dietary fats into molecules called “ketones.” She said these “serve as an alternative energy source for both the brain and the body.”
To reduce the intake of carbohydrates and support the supply of fats, therefore, the keto diet promotes consumption of “high fat, very low-carbohydrate foods such as animal proteins, full-fat dairy, healthy fats, and non-starchy vegetables,” according to Routhenstein.
People on the keto diet are encouraged to eat fewer carbohydrate-rich foods such as grains, fruits, starchy vegetables, legumes, and added sugars.
As a long-term eating regimen, the keto diet is associated with several risks.
Routhenstein noted the keto diet limits “fruits, whole grains, some vegetables, and legumes, limiting intake of essential vitamins, minerals, and fiber, which can affect negatively gut, brain, and heart Health.”
There are also concerns regarding increased cholesterol and soft arterial plaques, strained kidney and liver function, and an increased risk of bone loss.
In addition, the diet may lead to disordered eating and social isolation.
The keto diet has also been linked to increased oxidative stress, and the resulting increase in cellular senescence was investigated in the current study.
Much of the research regarding diets has focused on males’ responses to their effects. This is at least partially due to the relative complexities of female and male bodies and how they may affect responses to diets. An example would be the dynamic changes that occur within the female body across a woman’s estrous cycle, as opposed to a man’s body, which appears to be hormonally much the same all the time.
Jason Ng, MD, BA, teaches endocrinology and metabolism in the Department of Medicine at the University of Pittsburgh.
“It would be interesting,’ he said, “to assess the effects of diet on male and female sex hormones, such as estrogen for women and testosterone for men, and how diets may play a role in increasing or decreasing levels to a certain extent, and how that impacts the role these hormones have on their specific genders’ physiology.”
Ng noted that the insights suggested in this study of mice, however, must be viewed as preliminary.
“Although we can gain insight into metabolic processes through studies defining effects of a keto diet in mice, we do not yet extrapolate those findings in humans,” Ng said.
“There is much more heterogeneity in the findings of effects in humans, and gender effects are likely more varied as well, compared to mice data across genders,” he noted.
“If these results can be replicated in human beings, there is the possibility of this specific effect reducing the age acceleration in males, although this would, of course, have to be weighed against known side effects of estrogen therapy in men,” said Ng.
He added that it is unknown whether this therapy would need to be continued after the person had discontinued a keto diet.
Considering that the mechanism behind the increase in senescent cells appears in the study to be oxidative stress, might a purely antioxidant therapy be similarly effective for men on a keto diet?
“I think a purely anti-oxidant approach could also help reduce the aging effect to some degree,” hypothesized Ng.
“Maybe not as much of an influence as estrogen,” he suggested, “but certainly something that would be worthy of investigating more, as this approach could have a potentially lower side effect profile.”
“In some cases, particularly for specific medical conditions like epilepsy, a medically supervised keto or modified low carb approach can be beneficial,” Routhenstein pointed out.
“A cyclical or more flexible low carb plan may also work for certain individuals when guided by a qualified Healthcare provider,” she said.
Keto diet may not be heart-healthy in the long term“[T]o remain in true ketosis, carbohydrate intake must stay extremely low, something that is very difficult to maintain long term without compromising nutritional adequacy. As a cardiovascular dietitian and based on the current research, I do not recommend a ketogenic diet as a long-term heart-healthy strategy.”
— Michelle Routhenstein, MS, RD
“The potential risks outweigh the benefits, especially when more balanced, sustainable approaches are available and have been shown to improve heart health, inflammation, and longevity,” Routhenstein concluded.
