By Amber Roman
13 Oct 2024, 10:00 AM EDT
A new study carried out by the Jackson Laboratory (JAX) and published in the journal Nature has provided significant findings on the relationship between diet and longevity. In this extensive analysis, involving almost a thousand mice from various genetic lines, the influence of caloric restriction compared to intermittent fasting on life expectancy is examined. Unlike what had been observed in previous research, the results indicate that calorie restriction has a more positive effect on the longevity of these rodents than fasting practices.
Mice subjected to a calorie-restricted diet not only showed a longer lifespan, but also maintained stable body weight and energy levels, despite reduced food intake, as mice that experienced weight loss significantly tended to live shorter, raising questions about the relationship between weight control and long-term health. The results suggest that stress resilience and genetic factors are crucial determinants in how a diet can affect health and longevity.
The study challenges the conventional notion that metabolic markers, commonly used in human longevity research, are reliable indicators of life expectancy. Instead, scientists have found that immune health and red blood cell characteristics more accurately correlate with longevity. This opens new avenues for research into the impact of diet on aging and provides a basis for future studies in humans.
For nearly a century, research has shown that calorie-reduced diets or increased meal frequency can extend the lives of laboratory animals. However, until this study, understanding the mechanisms behind these effects had remained elusive. In a meticulous experimental design, the researchers ensured that each mouse was genetically distinct to better represent the diversity of the human population. This approach allows the results to be more relevant to human health.
The study’s findings revealed that mice on severely calorie-restricted diets (60% and 80% calorie reduction) lived, on average, 34 months, while those that ate freely only reached an average of 25 months. However, the variability in longevity within each group was notable, prompting the researchers to further examine the factors influencing these differences. Ultimately, genetic factors were determined to have a significant impact on life expectancy, suggesting that as-yet-unidentified underlying genetic characteristics play an essential role in how diet affects health.
Professor Gary Churchill, one of the study’s lead authors, emphasizes the importance of resilience. The more robust mice, which maintained their body weight and the health of their immune cells during periods of caloric restriction, were the ones that enjoyed greater longevity. This suggests that a moderate approach to calorie restriction may be the ideal path to balancing health and longevity.
The research also raises questions about traditional ideas regarding longevity, suggesting that factors such as body weight, fat percentage and glucose levels do not sufficiently explain the relationship between caloric reduction and life extension. Instead, the findings indicate that immune system health and red blood cell-related traits are more closely associated with long life.
The study has potentially profound implications for research on human aging. According to Churchill, it is crucial to note that although calorie restriction is generally beneficial for longevity, losing weight through this method might not be a good indicator of future life expectancy. The conclusion highlights that, while certain factors can be controlled throughout life, such as diet, genetics and resilience may be more influential determinants in the pursuit of a long and healthy life.
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