Washington: Dieticians often advise against late-night dinner as it may lead to weight gain. Now, a new study, led by an Indian-origin scientist, has found that wrong time eating may also cause reduced fertility, at least in the case of fruit flies.
Researchers at the Perelman School of Medicine at the University of Pennsylvania found that feeding fruit flies at the wrong time led to a defect in their reproductive ability.
The finding, published in the journal Cell Metabolism, however, may not hold true for humans and any potential link between diet and reproduction needs further research, Amita Sehgal, a neuroscience professor who led the research, said.
"I would not say eating at the wrong time of the day makes people less fertile, though that is the implication," said Sehgal.
"I would say that eating at the wrong time of the day has deleterious consequences for physiology."
Many aspects of animal biology cycle over the course of a day. Sleep and wakefulness, activity and rest, body temperature, and more, all fluctuate in a pattern called a circadian rhythm. Disruption of these rhythms has been shown to negatively affect physiology.
Shift workers, for instance, often suffer from psychological and metabolic issues that colleagues on normal hours do not, the researchers said.
In 2008, Sehgal`s team discovered that the fruit fly equivalent of the liver, called the fat body, has its own clock, which controls eating and food storage.
In the current study, they wanted to know what would happen if the fat body clock became desynchronized from the master clock in the brain.
First, she and her team found out which fly genes are controlled specifically by the fat body clock. Using gene chip microarrays, they identified 81 genes related to lipid and carbohydrate metabolism, the immune system, and reproduction that fit those criteria.
Next, they tried to decouple the fat body and central clocks by keeping the flies in constant darkness (to eliminate effects of light on these clocks) and feeding them at times when they don`t normally eat.
They found the two clocks could be desynchronised: disrupting the creatures` feeding cycles altered the cycling of genes controlled by the fat-body clock, but not those regulated by the central clock itself itself.
Finally, the researchers addressed the functional consequences of this desynchronization, by counting the number of eggs the flies laid under different conditions. Flies fed at the "right" time of the day deposited about 8 eggs per day, compared to about 5 when they fed at the "wrong" time.
"Circadian desynchrony caused by feeding at the wrong time of day leads to a defect in overall reproductive capacity," the authors said.
The next task, they said, is to finding the molecular mechanism that controls this phenomenon. And more importantly, to find whether this effect is restricted to fruit flies or it also occurs in higher organisms, including humans.