The Longevity Diet: Insights from Research

(4 minutes reading)

Lifespan in not the same than Healthspan

Aging is a natural and intricate physiological process influenced by numerous factors, some of which can be modified by our behaviours. It stems from a complex series of age-related declines at the molecular, cellular, tissue, and organ levels. These changes are categorized as the "Seven Pillars of Aging," which include:

1. Macromolecular damage

2. Epigenetics

3. Inflammation

4. Adaptation to stress

5. Proteostasis

6. Stem cells and regeneration

7. Metabolism

The root causes of these physiological deteriorations remain a subject of debate, with over 300 theories proposed to explain mammalian aging.

The interplay between primary and secondary aging is depicted schematically.

Primary aging is an inevitable outcome of living, driven by the accumulation of macromolecular damage over a lifetime. These processes are cyclic, and ongoing oxidative damage further promotes the generation of reactive oxygen species (ROS), ultimately compromising the homeostasis and function of cells and tissues, defining primary aging.

In contrast, secondary aging arises from external influences throughout life due to non-communicable diseases, environmental exposures, and social behaviors like overeating or low physical activity. These two intertwined factors encompass the seven distinct pillars of aging.

But what's the secret to achieving a longer and healthier life?

Scientists have found ways to extend the healthy lifespans of creatures such as worms, mice, and even monkeys long time ago. Their research has unveiled promising insights into the biology of aging. However, solid evidence still supports the age-old advice you likely received from your parents: maintain a healthy diet, engage in regular exercise, get ample sleep, and steer clear of unhealthy habits.

Studies demonstrate that adopting healthy behaviors can help you stay active and robust well into your 60s, 70s, and beyond. Notably, a long-term study of Seventh-day Adventists, a religious group known for their generally healthy lifestyle, reveals that they tend to enjoy better health in old age. Their life expectancy averages nearly 10 years longer than that of most Americans. The Adventists' longevity-promoting behaviors encompass regular exercise, a healthy diet, abstaining from tobacco and alcohol, and maintaining a healthy weight.

If we were to prioritize these behaviors, exercise stands out as the most crucial factor associated with increased longevity and improved health. Exercise, especially, enhances active life expectancy—life without disease and physical or mental impairments.

The initial randomized controlled trials (RCTs) of calorie restriction (CR) in healthy, non-obese humans were the CALERIE-1 and CALERIE-2 trials.

CALERIE-1 tested various modalities for inducing CR over 6–12 months, including calorie restriction, calorie restriction with exercise, and a very-low-calorie diet for rapid weight loss. CALERIE-2 subsequently assessed the most effective intervention for aging-related parameters, which turned out to be calorie restriction without exercise, studied over 24 months.

Evidence regarding the impact of prolonged CR on human aging comes from observational studies of members of the Calorie Restriction Society, who voluntarily practice self-imposed CR with Optimal Nutrition (CRON) in the belief that this dietary lifestyle will extend their lifespan. Those adhering to a CRON diet, known as "CRONIES," for 3–15 years have been reported to reduce their caloric intake by roughly 50% compared to a group of individuals with a typical Western diet.

Traditionally, exercise is defined as planned, structured, repetitive physical activity conducted with purpose. While resistance training significantly impacts both muscle and cardiometabolic health, most studies exploring lifelong exercise's impact on healthspan and lifespan, whether in pre-clinical or clinical models, have focused on endurance-based physical activities.

Lifelong exercise is associated with reduced risk of premature cardiovascular disease mortality and related risk factors like hypertension, hypercholesterolemia, and type 2 diabetes. Exercise enhances physiological functioning by increasing mitochondrial content and oxidative capacity, reducing oxidative stress, and improving protein quality control—factors that may attenuate primary aging.

Studies in humans show that regular exercise boosts mitochondrial oxidative capacity and partially normalizes enzyme activities in trained older adults compared to sedentary younger adults.

Insufficient levels of moderate to vigorous physical activity are consistently linked to reduced average lifespan, indicating accelerated secondary aging.

Researchers have found more evidence supporting the idea that CR, rather than exercise, reduces metabolic rate and lowers oxidative stress in humans, making it seem more effective at mitigating primary aging determinants. CR may be a superior lifestyle modification strategy for enhancing healthspan and promoting longevity by reducing metabolic rate and oxidative stress.

Clinical trials of exercise, on the other hand, do not consistently demonstrate these improvements.

Concerning secondary aging, both CR and exercise have been found to beneficially reduce adiposity. In summary, current literature suggests that CR yields more robust and sustained improvements in primary and secondary aging factors compared to exercise.

Nevertheless, a study by a Taiwanese research team concludes that when comparing active and inactive individuals, those in the low-volume activity group who exercised an average of 92 minutes per week, experienced a 14% reduced risk of all-cause mortality and a 3-year longer life expectancy.

Each extra 15 minutes of daily exercise, surpassing the minimum requirement of 15 minutes a day, led to an additional 4% reduction in overall mortality and a 1% decrease in cancer-related mortality.

These advantages extended to individuals of all age groups and genders, including those with cardiovascular disease risks. In contrast, those who remained inactive faced a 17% higher risk of mortality compared to individuals in the low-volume exercise group.