Healthy diet or good genes: A new study reveals which has a bigger impact on your lifespan | health

As people who research aging like to joke: The best thing you can do to increase your life is to choose good parents. After all, it has long been recognized that people with longer lives tend to have longer-lived parents and grandparents, suggesting that genetics influence longevity. How lifestyle versus genetics contributes is an open question that a recent study in Nature has shed new light on. Also read | Don’t expect human life expectancy to grow much more, we’re reaching a plateau, researcher says

Complicating the picture, however, is that we know that the sum of your lifestyle, specifically diet and exercise, also significantly influences your health into old age and how long you live.

More about the study

Scientists have long known that reducing calorie intake can make animals live longer. In the 1930s, it was observed that rats fed reduced calories lived longer than rats that could eat as much as they wanted. Similarly, people who are more physically active tend to live longer. But the specific link of single genes to longevity was until recently controversial.

While studying the lifespan of the tiny worm C elegans at the University of California, San Francisco, Cynthia Kenyon found that small changes in the gene that controls how cells sense and respond to nutrients around them made worms double their lifespan. This raises new questions: If we know that genetics and lifestyle affect how long you live, which is more important? And how do they interact?

To try to figure out the effects of genetics versus lifestyle, the new study in Nature examined different models of caloric restriction in 960 mice. The researchers specifically looked at classic experimental models of caloric restriction (20% or 40% fewer calories than control mice) or intermittent fasting of one or two days without food (as intermittent fasting is popular among people looking to see the positive). benefits of caloric restriction).

Because we now know that small genetic variations affect aging, the researchers specifically used genetically diverse mice. This is important for two reasons. First, because lab studies on mice are typically done on genetically very (very!) similar mice, this allowed the researchers to figure out what effects both diet and genetic variables would have on longevity.

Second, humans are very diverse, meaning that studies of genetically nearly identical mice do not usually translate into the high genetic diversity of humanity.

Diet counts, but genes count more

The main finding was that genetics appeared to play a larger role in lifespan than any of the dietary restriction interventions. Long-lived types of mice still had longer lives despite diet changes.

And while the shorter-lived mice showed improvements as a result of the dietary restrictions, they didn’t catch up with their longer-lived peers. This suggests that there is some truth to the “choose good parents” joke.

Caloric restriction models still increased lifespan in all types of mice, with the 40% restriction group having improved mean and maximum lifespan compared to the 20% group.

And the 20 percent group showed improvements in both average and maximum lifespan compared to the control group. It’s just that the effects of genetics were greater than the effect of dietary interventions.

Although all caloric restriction models resulted in an increase in the lifespan of the mice on average, the most extreme caloric restriction model tested (40 percent less group) saw changes that could be seen as physical damage.

These include reduced immune function and loss of muscle mass, which outside a predator- and germ-free laboratory environment could affect health and longevity. There are some important caveats to studies like this. First, it is not known whether these results apply to humans.

As with most research on calorie restriction in mice, the restricted-feeding groups ate 20 percent or 40 percent less than a control group that ate as much as they wanted. In humans, that would be like assuming that people eating every meal every day at a bottomless buffet is “normal.” And people who don’t eat from unlimited trays of food have “restricted eating”. This is not an exact parallel to how humans live and eat.

Second, although exercise was not controlled in any way in this study, most groups did similar amounts of running on their cage wheels, except for the 40% caloric restriction group that ran significantly more.

The researchers suggested that this extra exercise in the 40% group was because the mice were constantly looking for more food. But since this group exercised significantly more than the others, it could also mean that the positive effects of increased exercise were also seen in this group along with their calorie restriction.

What you should know

So while we can’t choose our parents or change the genes we inherit from them, it’s interesting to know that specific genetic variations play an important role in the maximum age we can aspire to.

The genetic cards we are given dictate how long we can expect to live. However, just as important in this study, lifestyle interventions such as diet and exercise that aim to improve lifespan should be effective regardless of what genes we have.

Disclaimer: This article is for informational purposes only and is not a substitute for professional medical advice. Always seek your doctor’s advice with any questions about a medical condition.