Restricting calorie intake, such as through intermittent fasting, not only improves physical health, but also contributes to healthy brain aging and increases life expectancy.
A new study involving experts from the University of Southern California (USC) examined which mechanisms a calorie-restricted diet has an impact on aging and life expectancy. The results are published in the specialist journal “Nature Communications”.
Study of fruit flies and human cells
According to the team, the current research work was carried out on around 200 fruit fly strains with different genetic backgrounds and also on human cells.
The flies were fed two different diets. The team either fed the flies regular food or gave the insects a severely restricted diet that was only 10 percent of their normal diet.
It turned out that the flies carried five genes that had specific variants that strongly influenced longevity in a restricted diet. Two of the genes had equivalents or counterparts in the human genome, the experts add.
The team selected one of these genes for closer examination. This gene is called mustard (mtd) in the fruit fly and oxidation resistance 1 (OXR1) in humans and mice.
What is the basis for protection against oxidative damage?
According to the researchers, it was already known that this gene protects cells from oxidative damage. The problem, however, was that the mechanism by which the gene exerts its effect remained unclear.
In humans, loss of OXR1 results in severe neurological deficits and premature death. In a model of amyotrophic lateral sclerosis (ALS), the addition of OXR1 improved the life expectancy of mice, the researchers report.
Effect of OXR1 on proteins
To find out how a gene active in neurons affects the entire lifespan, the team carried out various tests. It turns out that OXR1 affects a complex called retromer. This is a group of proteins that are necessary for the recycling of cellular proteins and lipids.
Restricted calorie intake slows brain aging due to the effect of mtd/OXR1 on retromer maintenance, the researchers say.
Protection of nerve cells
“This work shows that the retromer pathway, which is involved in the recycling of cellular proteins, plays a key role in protecting neurons when nutrients are limited,” explains study author Professor Dr. Pankaj Kapahi in a press release.
The experts found that mtd/OXR1 maintains the function of retromers and is necessary for neuronal function, healthy aging of the brain and extending lifespan with restricted nutrition.
“The gene is an important factor for the resilience of the brain, which protects against aging and neurological diseases,” adds study author Professor Dr. Lisa Ellerby added. Diet influences this gene. If you consume fewer nutrients, for example through intermittent fasting, the expression of the gene can be increased.
Longer life thanks to reduced nutrient intake
It was also shown that increasing mtd expression in flies leads to a longer life expectancy. According to the researchers, this suggests that excessive expression of OXR1 in humans could contribute to an extension of lifespan.
There are already plans to investigate which substances increase OXR1 concentrations during aging and thus slow down brain aging. This could also provide clues as to why the brain degenerates with age in the first place, the team adds. (as)
