Author: Matt Whitaker, Digital Health Lead/1 August 2019
Longevity in a lifecycle is defined as the duration of life. In humans the age in which we decease is thought to be heavily influenced by the environment we live in and the lifestyle we lead, whilst genetics play a smaller, yet still significant role, which is not fully understood.
Much has advanced in modern medicine and how healthcare tackles the burden of chronic conditions. Various pharmaceutical interventions and surgery procedures has led to humans managing to prolong lifespan, but not necessary health span.
Recently, The Government’s Green Paper, Advancing our health: prevention in the 2020s, has marked the official launch of Public Health England’s Predictive Prevention Programme. This has acknowledged that life expectancy has increased by almost 30 years over the past century; cancer survival rates have increased; and mortality rates from cardiovascular disease are down. It is also recognised that despite people living longer lives, over 20% of years lived are expected to be spent in poor health. The first 70 years of the NHS has succeeded in extending people’s lifespan but not health span (independent living, free of health deteriorating conditions). Extending health span is now a new priority outlined by the NHS.
Chronic diseases, such as: cancers; cardiovascular complications; musculoskeletal problems; depression, anxiety and mental health problems are the leading causes of death. To extend longevity we need to delay their onset. To do this we need to consider the primary drivers of health: the services we receive (public and private healthcare), the lifestyle we lead, the environment we live in and our genes (which we of course cannot influence).
There are a number of variables that have been proposed to maximise longevity which have indeed been studied, albeit mostly from an observational perspective with controlled trials almost exclusively occurring in animal models, for ethical reasons. These include:
1. Not overeating. Animal studies suggest modest energy restrictions (~30% total daily energy expenditure) may improve longevity. However many of these are flawed due to inconsistencies in food quality between groups. When energy restriction was applied to a group eating mostly whole, unprocessed food the effect is insignificant. If the restriction was applied to groups eating less nutritious, processed food the effect is more apparent which does beg the question- is it the energy restriction or the reduction in processed food consumption that is yielding the benefits in longevity?
2. Consider nutrient distribution. Macronutrient distribution is not as important, as long as carbohydrate is not consumed above tolerance i.e. glycaemic homeostasis can be maintained and protein is not consumed below positive nitrogen balance. Overall food quality does however matter, which the emphasis on the consumption of micronutrient dense, unprocessed foods. For example, Okinawans, in Japan live some of the longest lives reported and regularly consumed upwards of 85% of their calories from carbohydrate, yet consume little amounts of processed food, opting for a micronutrient rich diet.
3. Intermittently fast. Fasting has been discussed in a separate blog so I will not cover in detail here. But the primary correlations between fasting and longevity are linked with reduced insulin sensitivity, nutrient partitioning, glycaemic control and augmented autophagy.
4. Maintaining a healthy amount of body fat. I deliberately did not say body weight here as total weight is not as strongly associated with ill health outcomes as body fat. Carrying excessive body fat is arguably the primary driver of most chronic conditions, so maintaining healthy levels of stored fat coincides with delaying/avoiding these conditions.
5. Be physically active. In an ideal world progressive resistance based strength training should take precedence but if time permits incorporating endurance and/or interval style cardiovascular training will be beneficial. The benefits of being physically active and longevity come from: improvements in insulin sensitivity in muscle tissue; maintenance of muscle mass, functional ability, posture and strength; injury prevention and recovery; and increased glycogen capacity and glycaemic regulation.
6) Not smoking and limiting alcohol. Ultimately if longevity is your goal you should not smoke at all. In addition to this, limiting alcohol intake to at or below the UK Government guidelines of no more than 14 units per week will also be astute, especially if sugary alcoholic drinks are avoided and potentially health promoting drinks such as red wine take preference.
7. Manage stress and ensure happiness. Chronic stress is associated with poor glycaemic control, insulin resistance, overeating, weight gain and increased risk of chronic conditions. Learning how to manage or prevent stress certainly has a role to play in longevity. Linking in with this, maintaining a close social circle with friends and family has also been associated with longevity.
8. Sufficient sleep. Humans spend ~30% of their lives sleeping, it is clearly an essential peculiarity that we cannot out-evolve. Sleep is essential for our body to rest and recover, both from physiological and psychological perspectives. Sleeping well improves cognitive ability; improves glycaemic regulation; insulin sensitivity; regulates stress hormone secretion; and maintains circadian rhythm. It is debated whether quality or quantity are more important in sleep, with the likely, but undetermined answer been both share equal significance.
9. The environment in which we live. Those living in city centres tend to have lower life expectancies than those living in the country. This may be as a result of less exposure to pollutants; a more active, potentially less stressful lifestyle; different social behaviours with regards to dining out and drinking; and hypothetically a more diverse microbiome. Some observational research suggests populations newly moving into Western civilisation see a drop in life expectancy. This is certainly multifactorial but clearly the environment we live in plays a part in longevity.
10. Healthcare services. Don’t be scared of going to the doctors and pursuing symptoms- most chronic conditions can be prevented and the earlier they are recognised the better the chances of prevention. In the UK we are extremely fortunate to have a National Health Service that provides free healthcare- take advantage of this, without exploiting and live a healthier life.
One non-lifestyle related factor associated with longevity is rapamycin. Rapamycin is the only pharmaceutical substance that has increased lifespan in animals- including mammals. Trials have shown it to double the lifespan of yeast cells and increase lifespan of mice by 10-18%, in later life. The mechanism is that it inhibits mTORC1 which may regulate physiological aging and delay chronic disease onset. Inhibition of mTORC1 induces autophagy and as aging has the counter effect the use for rapamycin may delay the build-up of damaged cells and proteins within the body, this also reduces build-up of reactive oxygen species and inflammation. Rapamycin is not widely used for this reason due to dose dependant side effects which include: immunosuppression, hyperglycaemia and dyslipidaemia. Despite approval from the Food and Drug Administration, more research is needed before rapamycin can be claimed to increase longevity safely in humans.
To conclude, it has been argued that as average life expectancy increases, as does maximum life expectancy. Average life expectancy has increased massively over the past century and it cannot be accurately predicted what it may rise to in the next 100 years as science produces more innovative findings. As it is currently understood- the above factors in theory have the ability to increase both health and lifespan.
Any questions, feedback and/or suggestions would be most welcomed, as is any request for the research supporting this blog. Please email me at Matthew.Whitaker@xperthealth.org.uk