In today’s edition of far-out science, researchers have found evidence that the wafting aroma of food has an effect on an organism’s lifespan–and they’ve demonstrated that interfering with a fruit fly’s sense of smell causes it to live a longer, healthier life. While there’s no guarantee that the trick would work for humans, optimistic researchers suggest that certain odors—or drugs that block us from sensing them—might one day help prevent disease and extend lives [ScienceNOW].
In the past decade, scientists have established a clear connection between extremely low-calorie diets and extended lifespans; studies have demonstrated that yeast, fruit flies, mice, and monkeys on these diets live longer than their peers. While the exact mechanism at work isn’t yet clear, researchers suspect that a near-starvation diet causes an organism’s metabolism to slow down, and triggers other changes that evolved to help organisms survive in times when food was scarce. Now scientists say it may not be just what a creature eats, but also what it smells that has an effect on how long it lives.
In one 2007 study, molecular biologist Scott Pletcher and his colleagues found that completely eliminating fruit flies’ sense of smell caused them to live nearly 20 percent longer than normal flies. They also found that wafting the smell of yeast, a tasty treat for fruit flies, towards flies that were on a low-cal, live-extending diet hastened the death of those flies. This led the scientist to hypothesize that specific odors might be influencing the flies’ lifespans. Luckily, other scientists had identified a receptor in a group of neurons that enable fruit flies to smell carbon dioxide, which signals the presence of a good meal of tasty yeast [ScienceNOW]. So, Pletcher and his team set out to find if the CO2 had anything to do with the duration of the flies’ lives.
By deleting a single gene from a mouse’s genetic makeup, researchers have created a mighty mouse with a longer, healthier life. The change mimicked the effect of keeping the mice on a calorie-restricted diet. Severely restricting the diets of yeast, bacteria, mice and primates have granted these animals unnaturally long lives. For humans, however, maintaining a diet of near starvation would be difficult at best [Discovery News]. That’s why researchers are actively pursuing drugs that could produce the same anti-aging effect.
Study coauthor Dominic Withers says the effect was striking–but for reasons not yet understood, only the female mice benefited. The mice didn’t just live longer, they also had fewer age-related ailments. “These mice were resistant to type 2 diabetes … and they also appeared to have reduced incidence of the mouse-equivalent of osteoporosis — so they had stronger bones,” Withers said. Balance, strength and coordination all improved in the [female] mice, and they were more inquisitive, suggesting their brains were healthier [Reuters].
It’s been a big week on the longevity front: First, scientists found that an immunosuppresant drug called rapamycin extended the lifespan of mice. Now, a 20-year-long study reported in the journal Science shows that a diet 30 percent lower in calories than normal decreased the incidence of age-related diseases in macaque monkeys as the animals got older.
Half the monkeys were fed a low-calorie diet, and the other half a standard diet. All were closely monitored, with researchers regularly measuring their body composition, blood chemistry, endocrine function, and heart and brain function. When monkeys died, they were necropsied and the causes of death established [Wired.com]. Researchers found that monkeys on a calorie-restricted, nutrient-rich diet (on the left in photo) were three times less likely than monkeys on a full-calorie diet (on the right) to die from age-related diseases like cancer, diabetes, and heart disease. Scientists have hypothesized that calorie restriction triggers mechanisms that evolved to help organisms survive in times when food was scarce, but the exact process is still mysterious.
A drug that mimics the effects of a compound found in red wine has been shown to prevent obesity and diabetes in mice that were fed a high-calorie diet and prevented from exercising, taking another step towards the target of a anti-obesity pill. The natural compound found in grapes and red wine, called resveratrol, is believed to have numerous health benefits related to longevity, heart health, and metabolism. But tests in mice suggested gallons of wine would be necessary for humans to stand a chance of getting the same benefits. The scientists turned their attention to creating a more potent drug [BBC News].
The new experimental drug, called SRT1720, was developed by the pharmaceutical company GlaxoSmithKline. Researchers explain that mice fed a high-fat diet were tricked into switching their metabolisms to a fat-burning mode that normally takes over when energy levels are low…. “We are activating the same enzymes that are activated when people go to the gym,” said Peter Elliott, a vice president at Sirtris Pharmaceuticals, the Glaxo unit that developed the drug. “That is why we believe the profile for this drug is very safe” [Reuters].
This is the kind of medical news that always leads to people feeling happy and virtuous as they rush to the nearest liquor store. A new study has just revealed that resveratrol, a compound found in red wine, slowed down the genetic aging of middle-aged lab mice, and appeared to keep their hearts particularly young and healthy.
Of course, resveratrol is also found in grapes, pomegranates, and other foods, and medical researchers still don’t know whether the amount found in a glass of red wine has a clear effect on humans. But the report in the journal Public Library of Science ONE brings enough interesting and promising data to the table to warrant the popping of a few corks.