Since calorie intake has a comparatively large impact on natural variations in life expectancy, any genetic difference that systematically reduces calorie intake in some way should be correlated with increased longevity. So how about differences in the genes that determine taste? Here researchers search for signs of that correlation:
Several studies have shown that genetic factors account for 25% of the variation in human life span. On the basis of published molecular, genetic and epidemiological data, we hypothesized that genetic polymorphisms of taste receptors, which modulate food preferences but are also expressed in a number of organs and regulate food absorption processing and metabolism, could modulate the aging process.
Using a tagging approach, we investigated the possible associations between longevity and the common genetic variation at the three bitter taste receptor gene clusters on chromosomes 5, 7 and 12 in a population of 941 individuals ranging in age from 20 to 106 years from the South of Italy.
We found that one polymorphism, rs978739, situated 212 bp upstream of the TAS2R16 gene, shows a statistically significant association with longevity. In particular, the frequency of A/A homozygotes increases gradually from 35% in subjects aged 20 to 70 up to 55% in centenarians. These data provide suggestive evidence on the possible correlation between human longevity and taste genetics.
Given the broad role of this gene, the correlation with longevity may or may not have anything to do with a tendency to reduce calorie intake through differences in food preference.