Here’s how to ensure your biological age stays lower than your chronological one.
Age is just a number. You might strike up a conversation with someone after a cycling class and be shocked to find out that they’re a full two decades older than you. We’re all aging but our pace and performance as we age is highly variable. But scientists now understand more about why we age and how the choices we make can prove that age is just a number.
Knowing the key "nine hallmarks of aging" is crucial in figuring out how to optimize your lifestyle in a way that can add quality years to your life and optimize your day-to-day. Below, a doctor explains the science.
The 9 Hallmarks of Aging
1. Genomic instability
“Genomic instability refers to changes in DNA sequence that can lead to genetic diseases, including cancer,” explains Halland Chen, MD, a double board certified physician and longevity expert. Dr. Chen says that there are several different reasons why these changes in DNA sequence can happen—a few of which are directly related to diet and lifestyle habits.
For example, he says that exposure to environmental toxins and radiation as well as chronic inflammation can increase the rate of DNA damage. Dr. Chen says that these factors make DNA more prone to mutations than usual, which can then lead to disease, including Alzheimer’s, cardiovascular disease, and diabetes.
2. Telomere Attrition
Telomeres are DNA-protein structures found at the ends of chromosomes. Telomere attrition is another way of saying that the telomeres are getting shorter and this is a cause of aging because short telomeres are associated with an increased risk of disease. Not so coincidentally, Dr. Chen says that it’s another cause of genomic instability too.
But here’s the thing about telomeres: Dr. Chen says that there are certain lifestyle habits that can slow down the process of them shortening. This includes maintaining a healthy diet rich in antioxidants, regular exercise, stress reduction, getting adequate sleep, avoiding smoking or vaping, minimizing alcohol consumption, and protecting yourself from environmental pollutants. Dr. Chen says that taking omega-3 supplements may also help.
Unfortunately, you can’t just walk into your doctor’s office and ask for a test to know how long your telomeres are and if they’re getting shorter. What’s more telling, he says, is seeing an increase in the symptoms of aging, such as increased fatigue, becoming more susceptible to illnesses, and slower recovery from injuries. “These may all be indications that telomeres are shortening,” he says.
3. Epigenetic alterations
“Epigenetic alterations are changes in the regulation of genes,” Dr. Chen says, adding that this is different from genomic instability, which refers to changes in the DNA sequences itself. What they have in common is that both can lead to disease, which is why both are causes of aging. “Epigenetic changes can turn genes off or on, and can affect how cells divide and differentiate,” Dr. Chen says.
Dr. Chen explains that epigenetic alterations play a significant role in aging because they can lead to changes in gene expression that can cause age-related diseases. “These changes can cause cells to become less responsive to signals from the environment, leading to a decrease in cellular function, which in turn can contribute to the aging process,” he says. Once again, he says that these changes are influenced by diet and lifestyle. Stress, not getting enough sleep, an unhealthy diet, and smoking or vaping can all lead to these changes.
4. Loss of proteostasis
As the body ages, cells accumulate damaged proteins, which can then lead to age-related diseases. This accumulation along with protein-building failure is known as loss of proteostasis, the fourth hallmark of aging. Dr. Chen says that just as chronic inflammation and poor nutrition can cause the other hallmarks of aging, it comes into play here too, however, Dr. Chen says it’s also something that happens inevitably over time as a natural part of the aging process.
5. Deregulated nutrient-sensing
It’s common knowledge that the body needs nutrients to function, but the body also needs to know how to store nutrients to save for later and access them when we need them. It’s up to our cells to be able to sense nutrient levels. But over time, cells stop performing this job as efficiently, which is known as deregulated nutrient-sensing.
“As cells age, they may become less sensitive to certain nutrients and growth factors, which can affect their ability to divide and function properly,” Dr. Chen says, explaining why this is considered a cause of aging. This can lead to having low energy levels and can slow metabolism.
Deregulated nutrient sensing happens naturally as we age, but the less stress we put on our cells the better. Scientific studies show that eating a diet full of nutrient-rich foods and reducing calorie intake as we age can help. A study published in the journal Cell Metabolism found that reducing calories by 15 percent for two years can slow the aging process. If you’ve ever wondered why it can be harder to lose weight the older you get, this is one reason why!
6. Mitochondrial dysfunction
Mitochondria help turn the energy we consume through food into energy the body can use. They also play a role in cell growth and protecting cells from harm. Over time, mitochondria become less efficient at doing their job, known as mitochondrial dysfunction. “This decline can lead to fatigue, reduced physical and mental performance, as well as a weakened immune system. It can also lead to increased oxidative stress, damage to our DNA, and an increased risk of developing age-related diseases,” Dr. Chen says.
You can probably guess the best ways to keep your mitochondria functioning their best—keeping chronic inflammation away, regularly exercising, eating a nutrient-rich diet, managing stress and getting enough sleep all come into play here. Dr. Chen says that some studies have shown that supplementing with vitamins C, E, and lipoic acid (all antioxidants) may also protect mitochondria from damage.
7. Cellular Senescence
Cellular senescence occurs when cells can no longer divide and replicate and is something that happens naturally over time. “The exact point at which cellular senescence starts to occur can vary depending on the type of cell and the individual, but it is generally considered to be a gradual process that begins in early adulthood,” Dr. Chen says.
Remember how telomeres shorten over time? Dr. Chen says that this is one cause of cellular senescence. He explains that when telomeres become too short, cells can no longer divide and replicate. So look after your telomeres (again by doing what you can to keep chronic inflammation away) and you’ll also be prolonging cellular senescence. Dr. Chen adds that DNA damage, oxidative stress, and inflammation (yep again) can all contribute to cellular senescence directly too.
8. Stem cell exhaustion
“Stem cell exhaustion is a gradual process that occurs as stem cells age and lose their ability to divide and differentiate into other cell types,” Dr. Chen says. Like cellular senescence, he says this typically starts happening in early adulthood. As the number of stem cells in the body decreases, various tissues lose their ability to repair and regenerate. Signs that this is happening include getting wrinkles (less stem cells mean less elasticity in the skin), thinning hair, muscle weakness, bone weakness, a decrease in lung function, and a weaker immune system.
“These physical signs can also be caused by other factors, such as a poor diet, lack of exercise, and chronic stress, and not everyone will experience all of these signs. Additionally, more research is needed to fully understand the relationship between stem cell exhaustion and the physical signs of aging,” Dr. Chen says.
9. Altered intercellular communication
The last hallmark of aging is altered intercellular communication. This is exactly what it sounds like: cells not being able to communicate as efficiently with each other over time. “As cells age, the process of intercellular communication can become impaired, leading to a decline in cellular function and the development of age-related diseases,” Dr. Chen says.
Want to support good cellular communication in your body? Everything that minimizes the other hallmarks of aging applies here too. “Regular exercise has been shown to improve intercellular communication by increasing the production of growth factors and other signaling molecules,” Dr. Chen says. When it comes to diet, he says to focus on minimizing sugar and getting adequate amounts of healthy fats and antioxidants which can help to protect cells from damage and improve intercellular communication. He also emphasizes the importance of managing stress and getting enough sleep. “Sleep is important for the repair and rejuvenation of cells, including intercellular communication,” he says.
While it’s helpful to know exactly what causes our bodies to age, the major takeaway is that the same diet and lifestyle habits work to keep them at bay for as long as possible. Focus on preventing chronic inflammation through diet and lifestyle habits and you’re knocking nine birds out with one stone.