As those who study aging like to quip: The best way to extend your life is to choose good parents.
After all, it has long been recognized that people who live longer tend to have parents and grandparents who live longer, suggesting that genetic factors influence lifespan.
However, complicating the situation is that we know that the sum total of your lifestyle, and specifically your diet and exercise, can also significantly impact your health and longevity later in life. How lifestyle differs from genetic factors is an open question, a recent study nature Got a new understanding.
Scientists have long known that reducing caloric intake makes animals live longer. In the 1930s, it was noticed that mice fed fewer calories lived longer than those fed as much as they wanted. Likewise, physically active people tend to live longer. But until recently, specifically linking a single gene to longevity was a controversial issue.
While studying the lifespan of the small worm C Nematodes Cynthia Kenyon of the University of California, San Francisco, has discovered that small changes in genes that control the way cells detect and respond to surrounding nutrients can double the lifespan of worms. This raises new questions: If we know that genetics and lifestyle affect how long you live, which one matters more? How do they interact?
In an attempt to unravel the effects of genetics and lifestyle, the new study nature Different caloric restriction models were examined in 960 mice. The researchers specifically looked at classic experimental models of caloric restriction (eating 20 or 40 percent less calories than control mice), or intermittent fasting, which involves not eating for a day or two (because intermittent fasting is more effective in those who want to see positive effects). Very popular among people) Benefits of caloric restriction).
Because we now know that small genetic variations affect aging, researchers specifically used genetically diverse mice. This is important for two reasons. First, because laboratory studies in mice are often conducted on mice that are very (very!) genetically similar, this allows researchers to tease out the effects of dietary and genetic variables on lifespan.
Second, humans are highly diverse, which means that studies of mice with nearly identical genes typically do not translate into high genetic diversity in humans.
The most important finding is that genetics appear to play a greater role in lifespan than any dietary restriction intervention. Despite the change in diet, the long-lived type of mice lived longer.
Diet is important, but genes are more important
While the shorter-lived mice did show improvements in response to dietary restriction, they did not catch up with their longer-lived peers. This shows that the joke about “picking good parents” has merit.
The caloric restriction model still extended the lifespan of all types of mice, with the average lifespan and maximum lifespan of the 40% caloric restriction group being longer than that of the 20% caloric restriction group.
The 20% group showed improvements in mean and maximum lifespan compared to the control group. It’s just that the influence of genetics is greater than the influence of dietary intervention.
While all caloric restriction models increased the average lifespan of mice, changes that could be considered physical harm were observed in the most extreme caloric restriction model tested (a 40% reduction in the group).
These include decreased immune function and loss of muscle mass, which outside of a predator-free and sterile laboratory environment may affect health and lifespan.
There are some important caveats in such studies. First, it’s unclear whether these results apply to humans.
As with most caloric restriction studies in mice, the restricted group ate 20 or 40 percent less than the control group, which was allowed to eat as much as they wanted. To humans, this is like assuming that it’s “normal” for people to eat every meal from an all-you-can-eat buffet every day. Those who do not eat from the unlimited tray are said to be “restricted feeders”. This is not exactly similar to how humans live and eat.
Second, although exercise volume was not controlled in any way in this study, most groups performed a similar amount of running on the caged running wheel, but the 40% caloric restriction group performed significantly more running.
The researchers believe this extra movement in the 40 percent group was because the mice were constantly looking for more food. But since this group of people exercised much more than others, it could also mean that positive effects of increasing exercise in addition to caloric restriction were seen in this group.
So while we can’t choose our parents or change the genes we inherit from them, it’s interesting to know that specific genetic variants play a role in the maximum age we can expect.
The genetic card we receive determines our life expectancy. However, equally important in this study is the fact that lifestyle interventions aimed at extending lifespan, such as diet and exercise, should be effective regardless of what genes we have.
Bradley Elliott is Senior Lecturer in Physiology at the University of Westminster
(This article is republished from The Conversation under a Creative Commons license. Read the original article here.)
Published – October 21, 2024 at 04:50 pm (US Standard Time)