Neural tissue is one of the main oxygen consumers in the mammalian body, and a plentitude of metabolic as well as signaling processes within the brain is accompanied by the generation of reactive oxygen (ROS) and nitrogen (RNS) species. Besides the important signaling roles, both ROS and RNS can damage/modify the self-derived cellular components thus promoting neuroinflammation and oxidative stress. While previously, the latter processes were thought to progress linearly with age, newer data point to midlife as a critical turning point. Here, we describe (i) the main pathways leading to ROS/RNS generation within the brain, (ii) the main defense systems for their neutralization and (iii) summarize the recent literature about considerable changes in the energy/ROS homeostasis as well as activation state of the brain’s immune system at midlife. Finally, we discuss the role of calorie restriction as a readily available and cost-efficient antiaging and antioxidant lifestyle intervention.

It has recently been demonstrated that as the ratio of protein to carbohydrate (P:C) in the diet declines, life span increases in Drosophila. Here we explored how extremely low dietary ratios of protein to carbohydrate affected longevity and a selection of variables associated with functional senescence. An increase in P:C ratio from 1:57 to 1:20 shortened life span by increasing age-dependent mortality; whereas a further decline in P:C from 1:57 to 1:95 caused a modest decrease in life span. Female flies consuming the 1:20 and 1:38 diets laid more eggs than those consuming the lower P:C diets. Flies fed diets with higher ratios were more resistant to heat stress. Flies consuming the diets with lowest P:C ratios needed more time to restore activity after paralysis. Our study has therefore extended to very low P:C ratios available data demonstrating that dietary P:C ratio affects life span, fecundity and heat stress resistance, with fecundity and heat stress responses showing the opposite trend to life span.

The fruit fly, Drosophila melanogaster is a broadly used model for gerontological research. Many studies are dedicated to understanding nutritional effects on ageing; however, the influence of dietary carbohydrate type and dosage is still poorly understood. We show that among three carbohydrates tested, fructose, glucose, and sucrose, the latter decreased life span by 13%–27%, being present in concentrations of 2%–20% in the diet. Life-span shortening by sucrose was accompanied by an increase in age-independent mortality. Sucrose also dramatically decreased the fecundity of the flies. The differences in life span and fecundity were determined to be unrelated to differential carbohydrate ingestion. The highest mitochondrial protein density was observed in flies fed sucrose-containing diet. However, this parameter was not affected by carbohydrate amount in the diet. Fly sensitivity to oxidative stress, induced by menadione, was increased in aged flies and was slightly affected by type and concentration of carbohydrate. In general, it has been demonstrated that sucrose, commonly used in recipes of Drosophila laboratory food, may shorten life span and lower egg-laying capability on the diets with very low protein content.