Most people want to live a very long, financially stable, and happy life, or at least not a short and miserable one. If that’s you, you’re in luck, because over the past decade we’ve gone through an extensive research revolution in understanding the biology of aging.
The challenge is to turn that knowledge into advice and treatments; that we can benefit from. Here we bust the myth that extending healthy life expectancy is science fiction and demonstrate that it is scientifically possible.
1. Nutrition and Lifestyle:
There is ample evidence that doing boring things like eating healthy, is beneficial. A study of large groups of people shows that being at a healthy weight, not smoking, not drinking too much alcohol, and eating at least five servings of fruits and vegetables a day; can increase life expectancy by 7 to 14 years. And, that’s compared to someone who smokes, drinks too much, and is overweight.
Reducing calories even further, by about a third, known as food restriction; improves health and prolongs life in mice and monkeys, provided they choose good food, which is not always an easy option for humans. Unfortunately, we, as humans; are constantly exposed to temptations.
Less extreme versions; such as time-limited or intermittent fasting, where you only eat within an eight-hour window per day, or fast two days a week. These are practices thought to reduce the risk of age-related diseases in middle-aged people.
2. Physical activity:
While diet remains the most important thing for health, exercise is also important. Globally, inactivity is directly responsible for about 10% of all premature deaths from chronic diseases, such as coronary heart disease, type 2 diabetes plus various cancers. If every person on Earth started to exercise regularly for the next year; and starting tomorrow morning, it would likely increase the global human life expectancy by many years.
But how much exercise is optimal? Too much is not good either, and not just because of torn muscles and sprains. That’s because it can weaken the immune system and increase the risk of suffering from an upper respiratory infection. Just over 30 minutes a day of moderate to vigorous physical activity, is enough for most people. It will not only make us stronger and fitter, but it will also reduce harmful inflammation and improve our mood.
3. Strengthen the immune system:
Regardless of our physical condition and diet, the immune system, unfortunately, loses effectiveness with age. A poor response to vaccinations and an inability to fight infections are the consequences of this “immunosenescence”. Things start to go wrong in early adulthood when the thymus: a bow-tie-shaped organ located in the throat, begins to decline.
That sounds ominous, but it’s even more so when you consider that the thymus is where immune agents called T-cells first learn to fight off infection. The closure of such an important training center; means that the T-cells of older people “forget” how to recognize new infections or fight cancer effectively.
This can be remedied in part by making sure they get enough essential vitamins, especially A and D.
A promising area of research is looking at the signals the body sends to promote the production of immune cells, such as the IL-7 molecule. We may soon be able to design drugs that contain this molecule, which could strengthen the immune system after a certain age. Another approach is to use spermidine, a dietary supplement, to encourage immune cells to get rid of waste products, such as damaged proteins.
This method improves the immune system of older people so much that it is currently being tested, to get a better response to Covid vaccines in older people.
4. A rejuvenating cure for cells:
Senescence is the toxic state that cells acquire as they age. It wreaks havoc throughout the body and leads to chronic low-grade inflammation and disease, resulting in biological aging. In 2009, scientists showed that middle-aged mice lived longer and healthier lives if given small amounts of rapamycin, a drug that inhibits the mTOR protein, which helps regulate the cells’ response to nutrients, stress, hormones, and damage.
In laboratories, drugs like rapamycin (called mTOR inhibitors) make senescent (old) human cells look and behave like younger cells. Although it is too early to prescribe these drugs for general use, a new clinical trial has just been launched to evaluate whether low-dose rapamycin can actually slow aging in humans.
Discovered in the soil of Easter Island, Chile, rapamycin is shrouded in mystique and has been hailed by the popular press as a possible “elixir of youth”. It may even improve the memory of mice with a dementia-like disease.
All drugs have pros and cons, however, and because too much rapamycin suppresses the immune system, many doctors are reluctant to consider it to prevent age-related issues. However, newer drugs, such as RTB101, that work similarly to rapamycin, support the immune system of older adults and may even reduce the rates and severity of Covid infections.
5. Removal of old cells:
Getting rid of senescent cells altogether is another promising avenue. A few laboratories’ studies on mice with molecules that kill senescent cells; called “senolytics”, show an overall improvement in health. And because the mice don’t die of diseases, they end up living longer naturally.
Eliminating senescent cells is also beneficial for humans. In a small clinical trial, people with severe pulmonary fibrosis reported better overall function, including walking distance and speed, after receiving senolytic drugs. However, this is just the tip of the iceberg.
Diabetes and obesity, as well as diseases caused by certain viruses and bacteria, can increase the formation of senescent cells. These cells make the lungs more vulnerable to Covid-19. In fact, getting rid of senescent cells in old mice helps them survive Covid infection.
Aging and infections form a vicious cycle. When the immune systems start to fail, older people get more infectious diseases, which in turn accelerate aging by senescence. Because aging and senescence are closely linked to chronic and infectious diseases in the elderly, treating senescence could improve health.
It is exciting that some of these new treatments are already resulting in successful clinical trials, and may be available to everyone soon.