Eating is a necessity, but it also eats away at our longevity, suggests new research.
The findings could help to explain other studies linking fasting and low calorie diets to increased lifespan. The results were presented this week in Portland, Ore., at the 2016 annual conference of the Society of Integrative and Comparative Biology.
The problem is that consumption of all foods leads to oxidative damage, an increase in chemically reactive molecules containing oxygen that harms cells and DNA. Zach Stahlschmidt of the University of the Pacific and his colleagues believe that such damage can occur after our immune systems kick in whenever we eat.
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How this all affects aging had never been directly studied before, the researchers said. "It seemed like this is a hidden piece of the puzzle that .... might be really important, for lots of reasons," Stahlschmidt said in a press release.
In order to test their theory, Stahlschmidt and his team had to study an animal that eats infrequently, so they could distinguish normal amounts of circulating reactive oxygen molecules from those present after a meal.
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They chose to study the corn snake Pantherophis guttatus, which can survive on a one-mouse meal every two weeks. The scientists drew the snake's blood at peak digestion and post-absorption times to discover how the amount of oxidative damage was changing over time.
The researchers determined that oxidative damage increased by almost 180 percent during digestion. Conversely, antioxidant capacity - the ability of the body to fight the damaging effects of the oxidizing molecules - only increased by 6 percent. Each time the snakes ate, damage occurred that could affect their lifespan.
"The levels of damage we saw were really similar to or exceeded, by quite a bit, things as stressful as flying 200 kilometers (124 miles) in a bird, or mounting an immune response," Stahlschmidt said. "Both of these things seem really stressful and may induce oxidative damage, and they do, but much less than actually eating a meal."
The researchers suggest their findings could have ramifications for various animals, including humans and other mammals. Yet another reason to keep New Year's weight loss resolutions: Fewer calories could have you ringing in more years to come in future.