Keto diets may help improve memory and brain health in older adults

Researchers have identified a potential mechanism to explain the improvements seen in aging male mice on a ketogenic diet — or keto diet for short.

They suggested that alternating a normal diet with a ketogenic diet in male mice resulted in improved signaling between synapses in the brain.

Previously, John Newman, MD, a co-author of the paper, published a study showing that a cyclical ketogenic diet in male mice reduced the risk of death in midlife and prevented memory decline associated with normal aging.

“After reading two landmark papers published in 2017 that showed beneficial effects of the keto diet on the overall health of aged mice, including brain function, we decided to study the effect of the ketogenic diet,” said Christian González-Billout, a professor at the University of Chile, director of the Center for Research on Brain and Metabolism Aging (GERO), and adjunct professor at the Buck Institute for Research on Aging, and lead author of the new study on the keto diet and aging.

"In these two previous studies, the authors showed improvement in specific behavioral tasks that are routinely used in animal experiments to assess memory and learning," he continued.

“This improvement convinced us to delve deeper into the molecular mechanisms that explain this positive response, but also prompted us to include several other assessments at different levels, ranging from the whole-organism level to molecular functions, to understand why the diet was beneficial in older animals,” added González-Bihout, who collaborated with Newman on the recent study.

The team's latest results are published in the journal Cell Reports Medicine.

Keto Diet Linked to Lower Blood Sugar and Improved Memory

To further explore the previous findings, the researchers kept 19 male mice aged 20 to 23 months—considered "old age" in mice—on either a normal diet or a ketogenic diet, alternating with the normal diet every week.

During the first 12 weeks, the metabolic parameters of these mice were measured, and then for the next 5 weeks the mice continued their diet and underwent behavioral tests.

The results showed that the ketogenic diet was associated with lower blood sugar levels, improved memory and motor skills in aging mice. The researchers also showed that brain plasticity improved in the hippocampus of aging mice.

Further tests showed that this improvement in plasticity was linked to a molecule called a ketone body, which activated a signaling pathway between synapses when glucose levels were low.

"We focused on old mice because previous studies showed that the effect of diet on young animals was less pronounced. These previous data suggest that one of the beneficial roles of diet is to maintain resistance in aging mice, improving their physiological functions as they age," Gonzalez-Billout said.

Benefits of the Keto Diet for Seniors

In addition to animal studies, small human studies have suggested that the keto diet may be beneficial for cognitive function, particularly in older adults with dementia.

The mechanisms may be similar to those seen in animal studies, such as reduced inflammation, improved blood sugar control, and ketone body support for brain function. However, the research is still in the early stages, and larger clinical studies are needed to confirm these potential benefits.

Problems with following the keto diet

One of the main problems with the keto diet is that it can be difficult to follow due to the significant reduction in carbohydrates required. This can lead to a reduction in plant-based foods, which reduces your intake of fiber, vitamins, minerals, and antioxidants that are important for overall health.

Applicability of the study results to women

This study, like previous ones, was conducted only on male mice, which limits its applicability to humans, especially women. Women's metabolism processes fats differently than men's, which requires more research.

Future research

"Our next studies will focus on better understanding the molecular mechanisms involved in the beneficial effects of the diet in aging mice," Gonzalez-Billout said. "We also want to understand whether these effects in the brain are brain-specific or related to systemic effects in other organs."