Longevity Briefs: How To Live Longer By Looking After Your Metabolism

Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

Why is this research important: Changes in the metabolism – the ensemble of chemical processes occurring within the body – seem to have an important role in the ageing process. The earliest animal experiments showing that lifespan could be extended did so by targeting the metabolism. An unhealthy lifestyle, especially low physical activity and high calorie intake, slowly causes the metabolism to malfunction, which contributes to many age-related diseases. But what about people who remain exceptionally healthy well beyond average life-expectancy? What does the metabolism look like in these people, and can this teach us more about the ageing process and how we might be able to slow it down?

What did the researchers do: In this paper, researchers explore what we know about the metabolic changes that occur in old age. They also discuss the relationships between metabolic changes, longevity, and human data concerning interventions that are effective for maintaining a healthy metabolism.

Key takeaway(s) from this research:

The authors highlight the main metabolic changes that usually occur as part of normal ageing:

• Body weight increases by about 0.3 to 0.5 kg each year between ages 40 and 70. This is the result of increased fat tissue and reduced muscle tissue.
• Increasing age is associated with a reduced rate of energy expenditure. This is mainly the result of having less muscle tissue (which requires energy to maintain even at rest) and less physical activity.
• Ageing is associated with an increase in ‘bad’ visceral fat, which contributes to a number of health problems. You can read more about visceral fat and why it’s considered bad here.
• With increasing age, blood sugar tends to increase, which is largely a result of changes in muscle and fat tissue (again, you can read more about this in our series of articles on adipose tissue).
• The mitochondria, the power plants of the cell, become less efficient at producing energy, and generate more harmful by-products that lead to cellular damage.

The authors note that in comparison to the average person, centenarians (people who live to age 100) have been found to have better control over their blood sugar because their tissues respond better to insulin. This aligns with other research showing that sensitivity to insulin is associated with healthy ageing in many species. Differences in the fat tissue may also play a role. Fat doesn’t just store excess calories, but also regulates the metabolism by releasing various molecules including adiponectin, which seems to reduce the risk of some diseases. One study found that centenarians and their children have increased adiponectin levels.

Many of the habits practiced commonly among centenarians have been shown to improve metabolic health in human studies. Exercise is vital and resistance exercise may be particularly beneficial for limiting age-related changes in muscle tissue and improving insulin sensitivity. Some evidence also suggests that a higher protein intake is also necessary for older adults to derive the full benefit of exercise. Diets that sharply restrict calories, such as various forms of fasting, also appear to benefit metabolic health.

Since many people struggle to adhere to these practices, efforts are being made to find drugs that can mimic their effects. Resveratrol, for example, is a plant compound that some research suggests may preserve the health of fat and muscle tissue. The emerging strategy of destroying senescent fat cells (‘zombie’ cells that have lost their ability to divide) may also be an effective strategy for limiting these age-related changes.