Consumption of two common beverages - coffee and beer - may influence a person's life expectancy.
Experiments conducted by researchers from Tel Aviv University in Israel showed that coffee and beer left opposite effects on the length of telomeres - the sections of DNA found at the ends of chromosomes. While caffeine decreased length of telomeres, ethanol helped improve it.
Telomeres manage the ageing process by playing a major role in the division of cells. The length of telomeres becomes shorter with each stage of cell division. The process continues until the telomeres become too short, leading to cell death and ageing. Telomere shortening has long been known to damage immunity and increase risk of cancer.
Prof. Martin Kupiec and colleagues started their study as an investigation into Prof. Elizabeth Blackburn's (Nobel Prize-winning molecular biologist) 2004 study that linked emotional stress to shortening of telomere length, ageing and production of free radicals in the cells.
In the new study, Kupiec and team grew yeast cells and created free radicals. The yeast cells were exposed to 12 environmental stressors, including caffeine and ethanol. Even a small exposure to caffeine was found affecting the length of telomeres. On the other hand, exposure to ethanol left a positive impact on the length.
"For the first time we've identified a few environmental factors that alter telomere length, and we've shown how they do it," Prof. Kupiec, said in a news release. "What we learned may one day contribute to the prevention and treatment of human diseases."
While conducting further experiments, researchers identified two genes - Rap1 and Rif1 that play a major role in mediating between telomere length and environmental stressors. "This is the first time anyone has analyzed a complex system in which all of the genes affecting it are known," said Prof. Kupiec. "It turns out that telomere length is something that's very exact, which suggests that precision is critical and should be protected from environmental effects."
Findings have been published in PLOS Genetics.