What is the key to a long, healthy life? Is it the right diet or is it the genes? Researchers used mice to investigate which factor plays the greater role. It is one of the largest animal studies in this field.
Eating little prolongs life: This is indicated by many studies on various animal species . It is not yet completely clear what molecular mechanism is behind it and how it can best be activated in humans. A study on mice has now once again confirmed that a low-calorie diet can delay the time of death – but at the same time it has shown that genetic factors have a greater influence .
Experts working with Gary Churchill from the Jackson Laboratory in Bar Harbor (Maine) report on this in the journal “Nature”. Churchill and his group collected measurement data from around 1,000 laboratory mice. This is what it is according to “Nature” one of the largest food restriction studies ever conducted on laboratory animals.
The animals were selected to represent a wide range of genetic diversity. This should reflect the conditions in the human population and ensure that the results can be more easily transferred to humans.
Study monitored 1000 mice for life
The team randomly assigned the mice to different groups that differed in their food intake. There were five types of diets:
- unrestricted access to food,
- 80 percent or 60 percent of the amount consumed with unlimited access,
- and two different types of intermittent fasting.
The rodents were monitored for life, including regular blood tests.
As the analysis of the measurement data showed, a calorie reduction extended the lifespan of the animals more than periodic fasting. The more limited the calorie supply, the longer the lifespan – largely independent of body fat percentage or glucose levels, both of which serve as typical markers of metabolic health.
However, the mice that lived the longest with reduced food intake were also the ones that lost the least body mass despite starvation. In animals with significant weight loss, however, immune function and reproduction were impaired – and their lifespan was shortened.
Moderation brings benefits
Analysis of the experimental data showed that genetic factors had a greater influence on lifespan than diet. Mice that best maintained their body weight, body fat percentage and immune function during times of stress or starvation survived the longest – as did rodents that did not lose body fat in old age. “If you want to live a long life, there are things you can actively influence yourself, such as your diet. “But a grandmother who has become very old is even more useful,” comments Gary Churchill on these findings.
“Our study shows how important individual resilience is,” said Churchill. “Robust animals maintain their weight even under stress and calorie restriction, and at the same time they live the longest.” This suggests that calorie intake should only be moderately restricted. if you want to balance long-lasting health and life expectancy.
Important for a long life: intact immune and cardiovascular function
The research challenges common ideas about how diet and longevity are related. Factors such as body weight, body fat percentage, blood sugar levels and body temperature were only weakly correlated with lifespan in the study. Intact immune and cardiovascular function seemed to be more important. In other words: Metabolic status, which is often used as a measure of aging processes, may reveal less than previously thought.
Taken together, the results suggest that calorie restriction is generally good for life expectancy – but not if it leads to severe weight loss and its negative consequences.
