we Are known for Over a century Mice and rats are said to live longer when they are fed less food, but a new study suggests the secret may not be a lack of energy or protein, but an imbalance between the energy they eat and the energy they burn.
Researchers from the US and UK studied groups of mice fed the same diet and found that the mice kept in a cool environment lived longer and were healthier – with a key difference: they had to use more energy to keep themselves warm.
The findings suggest that studying energy intake alone is not enough to understand how diet affects health and ageing, said the team led by nutritionist Daniel Smith of the University of Alabama at Birmingham and biologist Sharon Mitchell of the University of Aberdeen in Scotland.
The discovery may mean that in the future, people may be able to achieve similar longevity benefits without following a strict diet.
“It’s not just about calorie intake or macronutrient intake or protein intake or any one factor,” Smith explained to Carolyn Beans. One PNAS Journal Club News Article About research.
“It’s their interaction with the overall energy balance.”
There is no consensus on the exact mechanisms by which reducing caloric intake positively impacts the health and lifespan of rodents.
One theory is that the benefits come from simply eating less food or reducing intake of certain macronutrients — some studies suggest that reducing intake of certain proteins may be a factor — or that the short-term energy imbalances that occur during calorie restriction could lead to longer-term health benefits.
The researchers propose that if the benefit was simply from reduced calorie and protein intake, health indicators should not differ between groups of mice if their food intake was the same, but if the benefit was due to less available energy due to the need to stay warm, then the lifespan and health of the “cold” mice should improve if their food intake was equivalent to that of the “warm” group.
In the study, a group of mice in a warm environment were given unlimited access to food for 12 hours per day, while mice in a cool environment were “pair-fed” to match the diet of the mice in the warm environment, ensuring the groups received identical calories, protein and other nutrients.
In a short-term experiment, mice were housed at 10 °C, 21 °C, or 30 °C for 11 weeks. Biomarker tests showed that mice housed in the cooler environment experienced hormonal, metabolic, and physiological benefits. The mice also lost weight more rapidly and maintained the weight loss.
In a longer-term experiment, mice were started at 12 weeks of age and followed for their entire lives. Mice kept at 22 °C lived approximately 20% longer than those fed the same diet but kept at 27 °C. Mice kept in cooler cages also showed improved health as they aged compared to mice kept in warmer cages. Mice kept in warmer cages showed a more rapid decline in balance, coordination and neurological function.
“Hence, energy balance (energy intake minus energy expenditure) was the main driver of the observed benefits,” the team said. write.
In this study, cold temperatures caused an energy imbalance, an effect that was not affected by drugs or exercise. However, the cold itself may have its own effects. Of course, for most people, enduring the cold to cause an energy imbalance is probably not realistic, and we don’t know if it would be good for us.
Researchers suspect that other factors, such as some medications, may also improve health by disrupting the body’s energy balance. It remains to be seen whether popular GLP-1 mimetics like Ozempic can achieve similar long-term health benefits.
“These results strongly suggest that dietary energy intake alone is not necessary to predict the health and longevity benefits of sustained dietary interventions,” the authors write. Conclusion.
The study was published in the journal Geroscience.
