Calorie restriction

Calorie restriction (CR) is used to improve longevity due to its multiple beneficial effects on various biological processes associated with ageing. Here are the key reasons why calorie restriction is considered to promote longevity:

1. Reduced Metabolic Rate and Oxidative Stress:

Lower Metabolic Rate: CR reduces the overall metabolic rate, leading to decreased production of reactive oxygen species (ROS), which are harmful byproducts of metabolism. Lower ROS levels reduce oxidative stress and damage to cells and tissues, which are major contributors to ageing.

2. Improved Cellular Maintenance and Repair:

Enhanced Autophagy: CR stimulates autophagy, a process where cells remove damaged components and recycle them. This helps maintain cellular health and function, preventing the accumulation of cellular debris that can contribute to ageing.

DNA Repair: CR can enhance the efficiency of DNA repair mechanisms, reducing the accumulation of genetic damage over time.

3. Hormonal and Metabolic Changes:

Insulin Sensitivity: CR improves insulin sensitivity, reducing the risk of type 2 diabetes and metabolic syndrome, which are associated with accelerated ageing.

Hormonal Balance: It can lead to favourable changes in hormone levels, such as decreased insulin-like growth factor 1 (IGF-1), which is linked to reduced cancer risk and longer lifespan.

4. Reduction in Inflammation:

Anti-Inflammatory Effects: CR reduces chronic inflammation, a key driver of many age-related diseases, including cardiovascular disease, cancer, and neurodegenerative disorders.

5. Cardiovascular Health:

Improved Heart Health: CR helps maintain healthy blood pressure, cholesterol levels, and other cardiovascular risk factors, contributing to a lower incidence of heart disease.

6. Sirtuin Activation:

Longevity Genes: CR activates sirtuins, a family of proteins involved in regulating cellular health, metabolism, and aging. Sirtuins are believed to play a role in extending lifespan by improving cellular function and stress resistance.

7. Enhanced Stress Resistance:

Adaptive Stress Response: CR triggers adaptive stress responses that make cells more resilient to environmental stressors, thereby reducing the risk of age-related damage.

8. Improved Cognitive Function:

Brain Health: CR has been shown to enhance cognitive function and protect against neurodegenerative diseases, likely due to its effects on reducing oxidative stress and inflammation, as well as improving metabolic health.

9. Extension of Lifespan in Model Organisms:

Research Evidence: Studies in various model organisms, including yeast, worms, flies, mice, and primates, have consistently shown that CR can extend lifespan and delay the onset of age-related diseases.

• Potential Epigenetic Effects:

Gene Expression: CR may influence gene expression patterns associated with ageing, leading to beneficial changes in cellular function and longevity.

While the exact mechanisms through which calorie restriction promotes longevity are still being studied, the cumulative evidence supports its role in enhancing healthspan and lifespan through multiple interconnected pathways.