by Cristina Brown
Genetics counts for only 25%: sedentary lifestyle, obesity, smoking and high blood sugar influence biological age and are related to a faster aging process
Can our body really be younger than the chronological age? Is it possible to improve our biological age? In recent months, the story of US multi-billionaire Bryan Johnson, 45, who claimed to be spending millions to reverse aging and regain his 18-year-old physique, has caused headlines. To achieve this, Johnson adheres to a strict diet, performs demanding physical exercises, takes supplements and undergoes frequent tests to analyze the functionality of his organs. followed by a team of about thirty people including personal trainers, doctors, nutritionists and even injected himself with the blood plasma of his 17-year-old son. Johnson claims that after two years of intense treatments he has reduced his epigenetic age by 5.1 years (here is his typical day).
The question that many ask themselves is whether the goal is really achievable. And above all if it is for all mere mortals who do not have the eccentric Johnson’s billions at their disposal and above all his time, since keeping young is a real job for him.
The measurements
In the meantime, let’s start by clarifying that there are two interconnected ways of measuring age. The first is the chronological age and is easy because it is nothing more than the time elapsed since the day one was born, and can be read on the identity card. And in case documents are missing (think of archaeological excavations) there are different techniques to estimate age such as the observation of teeth or bones. Biological age, on the other hand, reflects the exponential increase in the possibility of an organism getting sick or dying as time passes. Basically the speed with which the body loses its functionality.
Biological age separated from personal age
As most species age there are some rare creatures like the ocean quahog clam
, edible mollusk, which practically never gets old. However, as all living beings age, not all lose functional capabilities at the same rate, and the body can lose functionality at different rates. Two people born in the same year can have two states of health and two radically different aging processes
: This means that the biological age in some people may be higher or lower than their chronological age. An article published on The Conversation gives an emblematic example, that of a 70-year-old US marathon runner he set a world record for his age group in 2018. Many of his peers are in much more precarious health conditions, often cared for in nursing homes. This clearly demonstrates how biological age can be separated from chronological age.
How to estimate biological age
There are several ways to estimate biological age. It may seem surprising, but one of the best methods is also the simplest: use your eyes. Research shows that estimates made by observing someone are at least as good as some of the more complicated techniques.
Studies show that smokers, obese people or people in poor health are all perceived by their peers as older of their biological age. Since these factors actually increase biological age, this is evidence that observing someone is an accurate way of establishing their biological age.
Another important indicator of biological age is the measurement of hand grip with a test of strength, which tends to decrease with age as a result of the loss of muscle mass. Illnesses, obesity, lack of physical fitness also affect the ability to grip the hand. A low grip strength is a sign that your biological age is probably older than your chronological age. Other more complex methods of estimating biological age include multi-organ function tests and looking at inflammation that measure how many inflammatory molecules are circulating in the body (it’s not good news to have high levels of them). It is also possible to look at epigenetic changes in DNA, i.e. changes that tend to occur with age, or the number of senescent cells to measure one’s biological age. Numerous paid tests are available online (we wrote about them here) that promise to measure biological age. Even if these tests are based on serious scientific research, starting from the epigenetic clock developed in 2013 by Steve Horvath, a UCLA professor and industry pioneer who developed an algorithm that provides a highly accurate estimate of a person’s age (l ‘error less than two years), it is not easy to judge its validity, so much so that none has been approved by the FDA, the US agency for food and medicines.
How to stay young
To hopefully turn back the clock and reverse aging, the best starting point is to focus on lifestyle. Getting regular exercise, quitting smoking, drinking very moderately, controlling your weight and eating fruits and vegetables are all simple things that make a difference on biological age. There is about a 15-year difference in life expectancy between a person who does four of these five things and someone who does none, he says. Riccardo Faragher co-director of the BLAST Healthy Aging Network at the University of Brihton in his article published in The Conversation. In short, he has a healthy lifestyle a bit like an elixir of youth which, moreover, also acts at the level of our DNA, as indicated by a study published in the journal Circulation: Genomic and Precision Medicine. The authors studied the biological age of about 2,500 individuals by analyzing epigenetic modifications, i.e. those chemical alterations of DNA (particularly methylations) that influence gene expression and can in turn be influenced by environmental factors such as diet, lifestyle and stress. It emerged that cardiometabolic factors such as obesity and dyslipidemias were associated with an epigenetic acceleration of age as well as reduced physical activity. In addition, DNA methylation measurements performed one year apart in a subset of patients showed that other factors, such as high (minimum) diastolic blood pressure and elevated blood glucose (blood sugar) values, were also associated with an acceleration of ageing.
We often tend to blame or credit genes in relation to biological age but in reality only 25% of the speed at which we age is linked to genes, the rest depends on the environment: i.e. diet, exercise, social relationships, good habits which must be maintained for life but above all in the elusive middle age which goes more or less from 45 to 65 years, when the foundations are laid for a healthy third age.
Study treatments
There are also treatments in development that could rapidly and significantly reverse aging, although for now the results have been obtained in mice and it is not known if they will work in humans. For example, researchers have shown that the accumulation of senescent cells in tissues is a primary cause of aging in mice. Their removal has shown improvements in both their health and lifespan. These studies also compared the effects of removing senescent cells throughout the animal’s life with allowing them to accumulate and then removing them when the mouse was old. Both interventions improved the health and lifespan of the mice, and the removal of senescent cells at an older age could represent the reversal of aging. Many attempts are underway to duplicate these effects in humans but the road is still quite a long way. Maintaining an active lifestyle remains for now the best way to stay young.
August 21, 2023 (change August 21, 2023 | 18:55)
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