Diet holds key to all our health related concerns however, a new study has demonstrated for the first time link between diet, circadian rhythms, eye health and lifespan in Drosophila. The findings are published in Nature Communications. Scientists have also found that processes in the fly eye are actually driving the aging process.
While previous studies have established relationship between eye disorders and poor health, the new study argues that it is more than correlation: dysfunction of the eye can actually drive problems in other tissues. Researchers were able to show that not only does fasting improve eyesight, but the eye actually plays a role in influencing lifespan.
The explanation for this connection researchers say lies in circadian “clocks,” the molecular machinery within every cell of every organism, which have evolved to adapt to daily stresses, such as changes in light and temperature caused by the rising and setting of the sun. These 24-hour oscillations – circadian rhythms – affect complex animal behaviors, such as predator-prey interactions and sleep/wake cycles, down to fine-tuning the temporal regulation of molecular functions of gene transcription and protein translation.
Researchers noticed numerous genes that were both diet-responsive and also exhibiting ups and downs at different time points, or “rhythmic.” They then discovered that the rhythmic genes that were activated the most with dietary restriction all seemed to be coming from the eye, specifically from photoreceptors, the specialized neurons in the retina of the eye that respond to light.
This finding led to a series of experiments designed to understand how eye function fit into the story of how dietary restriction can extend lifespan. For example, they set up experiments showing that keeping flies in constant darkness extended their lifespan.
Since the eyes are exposed to the outside world, researchers explained, the immune defenses there are critically active, which can lead to inflammation, which, when present for long periods of time, can cause or worsen a variety of common chronic diseases. Additionally, light in itself can cause photoreceptor degeneration which can cause inflammation.