Fasting boosts "longevity gene" to improve long-term memory in mice
Fasting diets in their many forms have gained serious popularity as effective ways to lose weight, but researchers studying the physiological underpinnings continue to show how they might do much more than that. Scientists at King's College London have used experiments in mice to demonstrate how fasting can also improve long-term memory and tackle age-related cognitive impairment, by boosting expression of what's known as the "longevity gene."
In recent years, we've seen a string of studies illuminate the potential benefits of fasting. These include an expansive and fascinating range of outcomes, such as remodeling the gut microbiome, improving the efficacy of cancer treatments, boosting the body's ability to clear away toxic proteins like those linked to Alzheimer's, and altering the mitochondria in our cells to slow aging.
The new study also sheds light on how fasting might lead to an improved health-span. The authors conducted experiments in which female mice were divided into three groups with their own eating regimes: one on a standard daily diet, another on a calorie restricted diet and one on an intermittent fasting (IF) diet, in which they only ate every second day. Both the calorie restricted and IF groups consumed 10 percent fewer calories than the control.
This took place over a three-month period, after which the IF group demonstrated heightened long-term memory compared to the other groups. Studying the brains of this group of rodents revealed an uptick in the expression of a gene called Klotho, referred to as the longevity gene due to decades of scientific literature linking it to the aging process in mammals.
One of the byproducts of this over-expression of Klotho, the researchers found, was an increase in the production of new neurons on the hippocampus, or neurogenesis, which play an important role in memory formation. Production of these neurons typically declines with age and, interestingly, the scientists found that only through IF were the mice able to buck this trend and exhibit an increase in neurogenesis.
"We now have a significantly greater understanding as to the reasons why intermittent fasting is an effective means of increasing adult neurogenesis," says study author Dr Sandrine Thuret from King's. "Our results demonstrate that Klotho is not only required, but plays a central role in adult neurogenesis, and suggests that IF is an effective means of improving long-term memory retention in humans."
While the findings suggest that IF is superior to calorie restricted diets, at least in terms of long-term memory, and similar processes might be at play in humans, there are no guarantees. The researchers now plan to build on the promising results of their study by recreating it with human subjects.
The research was published in the journal Molecular Psychiatry.