Ketogenic diet may prevent cognitive decline, says study

Washington: Following a ketogenic diet -- a high-fat, low-carbohydrate regime -- may boost cognitive abilities, a study in mice suggests.

Researchers from University of Kentucky in the US showed that the gut and the brain are more closely connected than we once thought, and in fact the health of one can affect the other.

"Neurovascular integrity, including cerebral blood flow and blood-brain barrier function, plays a major role in cognitive ability," said Ai-Ling Lin, from University of Kentucky.

"Recent science has suggested that neurovascular integrity might be regulated by the bacteria in the gut, so we set out to see whether the Ketogenic Diet enhanced brain vascular function and reduced neurodegeneration risk in young healthy mice," said Lin.

The Ketogenic Diet has previously shown positive effects for patients with other neurological disorders, including epilepsy, Parkinson's disease, and autism.

For the study published in the journal Scientific Reports, two groups of nine mice, aged 12-14 weeks, were given either the Ketogenic Diet (KD) or a regular diet. After 16 weeks, researchers saw that the KD mice had significant increases in cerebral blood flow, improved balance in the microbiome in the gut, lower blood glucose levels and body weight, and a beneficial increase in the process that clears amyloid-beta from the brain -- a hallmark of Alzheimer's disease.

"While diet modifications, the Ketogenic Diet in particular, has demonstrated effectiveness in treating certain diseases, we chose to test healthy young mice using diet as a potential preventative measure," Lin said.

"We were delighted to see that we might indeed be able to use diet to mitigate risk for Alzheimer's disease," she said.

According to Lin, the beneficial effects seen from the Ketogenic Diet are potentially due to the inhibition of a nutrient sensor called mTOR (mechanistic target of rapamycin), which has shown to effect lifespan extension and health promotion.

In addition to the Ketogenic Diet, Lin said, mTOR can also be inhibited by simple caloric restriction or the pharmaceutical rapamycin.

Another study, published in the journal Frontiers in Aging Neuroscience, used neuroimaging techniques to explore in vivo the effects of rapamycin, the Ketogenic Diet, or simple caloric restriction on the cognitive function of both young and aging mice.

"Our earlier work already demonstrated the positive effect rapamycin and caloric restriction had on neurovascular function. We speculated that neuroimaging might allow us to see those changes in the living brain," Lin said.

The data suggested that caloric restriction functioned as a sort of "fountain of youth" for ageing rodents, whose neurovascular and metabolic functions were better than those of young mice on an unrestricted diet.

Researchers emphasise that it is too early to know whether the regimens will confer the same benefit in humans, but since rapamycin and other mTOR inhibitors have already been approved by the FDA and are widely prescribed for other diseases, a study in humans could follow relatively quickly.

All of the methods researchers used in animal models can be readily applied to humans.