EFFECT OF DIETARY-FAT ON LONGEVITY OF DROSOPHILA-MELANOGASTER

The effects on the lifespan of adult male Drosophila melanogaster of replacing dietary glucose by fructose, glycerol or one of a variety of fats has been studied. Isocaloric replacement of glucose by fructose or glycerol has no significant effect on lifespan but substituting lard, butter, margarine, dripping or palmitic acid for glucose led to a significant reduction in lifespan. A detailed study of the nature of the life shortening produced by one of the fats, palmitic acid, suggested that most of the life shortening effects are due to rapidly reversible processes, but approximately 20% of the life shortening effects persist irreversibly when transferred back to a low fat medium. This suggests that a high fat medium may accelerate the ageing process. In contrast, a short exposure to palmitic acid early in the life of the flies produces an irreversible increase in the life expectancy which is very variable. This may be due to an action on endogeneous microflora. © 1979.