An increased need for dietary cysteine in support of glutathione synthesis may underlie the increased risk for mortality associated with low protein intake in the elderly

Abstract

Restricted dietary intakes of protein or essential amino acids tend to slow aging and boost lifespan in rodents, presumably because they downregulate IGF-I/ Akt/mTORC1 signaling that acts as a pacesetter for aging and promotes cancer induction. A recent analysis of the National Health and Nutrition Examination Survey (NHANES) III cohort has revealed that relatively low protein intakes in mid-life (under 10 % of calories) are indeed associated with decreased subsequent risk for mortality. However, in those over 65 at baseline, such low protein intakes were associated with increased risk for mortality. This finding accords well with other epidemiology correlating relatively high protein intakes with lower risk for loss of lean mass and bone density in the elderly.

Nutraceuticals have potential for boosting the type 1 interferon response to RNA viruses including influenza and coronavirus

“…The particular utility of NAC in the elderly might reflect the fact that plasma cysteine levels and cellular glutathione levels tend to decline with advancing age. 20 Since selenium is an essential cofactor for certain peroxidases, and selenium deficiency has been endemic in certain regions of China and other parts of the world, insuring adequacy of selenium nutrition might also be appropriate in this context. 21 Not surprisingly, influenza is more pathogenic in selenium-deficient mice, and selenium deficiency also increases the rate at which viruses can mutate, promoting the evolution of strains that are more pathogenic and capable of evading immune surveillance.…”

Nutrition and the gut microbiome in the elderly

“…89 Additionally, the actual nutritional needs of the older population can differ from those of the middle-age. 90 Therefore, nutritional strategies in the elderly should be addressed from a holistic perspective, considering the intestinal microbiota, the immune system as well as nutritional deficiencies and needs as a whole (Fig. 2).…”

High-Concentrate Diet-Induced Change of Cellular Metabolism Leads to Decreases of Immunity and Imbalance of Cellular Activities in Rumen Epithelium

“…Arginine metabolism plays an important role in host defense and tissue repair [29]. Cysteine is the major component of glutathione, whereas glutathione metabolism is reported to be beneficial to cell health and functions both by acting as an oxidant scavenger and by opposing the pro-inflammatory influence of hydrogen peroxide on cell signaling [30]. Furthermore, lipid metabolism is exclusively upregulated under the energy-rich status.…”