A recent study has demonstrated that a ketogenic diet significantly improved memory in aging mice and increased the animal’s chances of surviving to old age, opening up a new area of inquiry in aging research.
Eating a ketogenic diet – which is high in fat and low in protein and carbohydrates – ramps up the number of ketone bodies. In this study, Newman et al. carefully designed three diets that were matched in every way except fat and carbohydrate content: a normal high-carbohydrate diet, a zero-carbohydrate ketogenic diet, and a high-fat, low-carbohydrate diet that was not ketogenic. Mice were fed the ketogenic diet intermittently to prevent them from becoming obese, starting at one year old, which is middle age for mice.
The ketogenic diet-fed mice had a lower risk of dying as they aged from one to two years old, although their maximum lifespan was unchanged. Another group of mice underwent memory testing at both middle age (one year old) and old age (two years old). Mice that had been eating a ketogenic diet performed at least as well on memory tests at old age as they did at middle age, while mice eating the normal diet showed an expected age-associated decline. Mice who ate the ketogenic diet also explored more, and their improved memory was confirmed with another test a few months later.
According to the paper, gene expression could explain the cognitive improvement. Future work to understand the nature of the persistent effect on memory in particular may lead to therapies to promote cognitive resilience to dementia or illness-associated delirium.