Your Biological v. Chronological Age

I turn 52 next month. There is no stopping my birthday from coming and I like my birthday, so it is OK. Going from 51 to 52 is inevitable. This is my chronological age which is measured in the years I have been alive.

But I also have a biological age. What you ask? Two ages, isn’t 1 enough?

Your other age is your biological age. Your biological age is “the true age that our cells, tissues, and organ systems appear to be, based on biochemistry.” It is determined by various biomarkers “that could predict functional capacity at some later age better than chronological age.”

The difference between biological and chronological age has tremendous implications for how we think about aging. Getting biologically older does not have to move in lock step with getting chronologically older.

Below I discuss the 9 Hallmarks of Aging (biologically) scientists have agreed upon as well as steps you can take to positively influence these factors. The fact that your chronological age and biological age can be different, and you can influence this through diet and lifestyle is exciting!

The 9 Hallmarks of Aging

In 2013 a group of scientists published a paper, The Hallmarks of Aging. In this paper they outlined what they believe are 9 main drivers of aging. These primary drivers are telomere attrition, genomic instability, epigenetic alterations, loss of proteostasis, cellular senescence, mitochondrial dysfunction, altered intracellular communication, de-regulated nutrient sensing, and stem cell exhaustion.

Yup, this didn’t mean anything to me from a practical perspective, so I dug a little deeper. Stick with me, I promise it is worth it!

Telomere Attrition

Telomeres are important for the overall function of your chromosomes and prevent important DNA from being lost with every replication.  They protect the ends of chromosomes by forming a cap at the end of each strand of DNA, kind of like the plastic end of a shoelace.

“Telomeres shorten naturally as people age, but certain factors – such as obesity and smoking – increase the speed at which the process occurs. A UCSD study found that physical inactivity and a sedentary lifestyle also cause cells to age more rapidly.”

 Genomic Instability (DNA damage)

DNA is what tells our cells what to do and how to act. DNA stability and integrity is challenged over time by both internal and external factors. DNA damage occurs when your DNA replicates but does not copy itself perfectly. If there are too many errors than the cell can malfunction. This could result in something such as cancer. And while our body has mechanisms to repair errors in our DNA these mechanisms don’t always catch all the errors. 

This article highlights 11 scientifically backed ways to protect your DNA, including getting adequate sleep, exercising regularly, incorporating caloric restriction and fasting, eating a healthy diet. To additionally protect your DNA wear sunscreen, limit exposure to X-rays and chemicals known to cause cancer, don’t smoke or use other tobacco products and limit foods containing nitrates. And according to a study in PubMed, “adequate levels of vitamin D may also be beneficial in maintaining DNA integrity.”

Epigenetic Alterations (gene expression errors)

This concerns which genes get expressed (turned on) and which are not (or silenced). As we age this process can become less robust resulting in expression errors.

A 2013 paper says, “Increasing evidence shows that environmental and lifestyle factors may influence epigenetic mechanisms, such as DNA methylation, histone acetylation and microRNA expression.” Lifestyle factors include nutrition, behavior, stress, physical activity, work habits, smoking, and alcohol consumption. Yet another plug for living as healthy as possible.

Loss of Proteostasis

Proteins control most cell functions. However, they lose their functionality and must be recycled over time. As we age this recycling process becomes less robust and then we accumulate too many old proteins which can become toxic.

Protein build up in the cells is responsible for many neurodegenerative diseases, like Alzheimer’s and Parkinsons.

“A study by researchers at UCLA's Semel Institute for Neuroscience and Human Behavior has found that a healthy diet, regular physical activity and a normal body mass index can reduce the incidence of protein build-ups that are associated with the onset of Alzheimer's disease.”

Cellular Senescence

“Zombie” or senescent cells occur when a cell undergoes some sort of stress and stops dividing but doesn’t die. Too many of these types of cells leads to inflammation and disease.

Scientists are testing drugs designed to kill zombie cells, called senolytics, on mice. “When drugs targeting those cells were given to aged mice, the animals showed better walking speed, grip strength and endurance on a treadmill. Even when the treatment was applied to very old mice, the equivalent of people ages 75 to 90, it extended lifespan by an average of 36 percent.”  

“The human immune system is naturally designed to identify and get rid of these cells. One of the ways to slow cellular senescence is to support your immune system and to take substances which are designed to target zombie cells.” These substances include Quercetin, Piperlongumine, and Fisetin. Fasting also supports your body in getting rid of Senescent cells.

A pharmaceutical option is the diabetes drug Metformin. And lastly, scientists have also developed (and are working on more) drugs to clear these zombie cells.

Mitochondrial Dysfunction

Your mitochondria are the energy powerhouses of your cells. They produce ATP which provides the energy for most cellular processes. As you and your cells age, your mitochondria can become less efficient at producing energy and not work as they are intended. And “when they don't function properly, they can produce an altered form of oxygen that can cause damage to DNA and proteins.” 

Like everything else, diet and lifestyle can help protect your mitochondria. Eat fruits and veggies, engage in strength training, avoid exposure to toxic metals, be careful of certain drugs (acetaminophen, antibiotics, statins, etc.) and don’t imbibe too much alcohol. Specifically make sure you are getting enough of all the B vitamins and “mitochondrial supportive nutrients…CoQ10, a-lipoic acid plus acetyl-l-carnitine, resveratrol, NAC, and vitamin E. Also of value are coconut oil, PQQ, Ginkgo biloba, proanthocyanidins, and melatonin.” This article gives specific recommendations for dosages.

Altered Intracellular Communication

Healthy cells are constantly sending messages to each other. When these communication systems break down messages can get “lost” and our immune systems can become less efficient at getting rid of dead and zombie cells, which can lead to increased inflammation.

I was not able to find any specific recommendations to support cell metabolism to share. But I would hazard a guess that a healthy diet and active lifestyle can’t hurt!

Deregulated Nutrient-Sensing

Your cells are responsible for processing nutrients (fats, sugars, etc.). If they don’t sense and process them accurately this can lead to imbalances within the cells. These imbalances contribute to inflammation which is a contributor to aging.

Focusing on a healthy diet and active lifestyle are important for supporting your cells work.

Stem Cell Exhaustion

Stem cells are unique cells which can become different types of cells. They replicate rapidly and are critical to the body’s healing process. “As humans age, stem cells become exhausted and less active, which means they can't divide as quickly. The exhaustion of stem cells means that tissues that are supposed to get renewed do not actually renew.”

According to this article, following a healthy diet, not smoking & limiting alcohol, being active & exercising, avoiding toxic chemicals, getting good sleep and avoiding certain medications can all help support and protect your stem cells.

How to Test Your Biological Age

“Researchers have found that DNA methylation is the only biomarker that meets criteria to be considered a marker for biological age.” Several companies offer biological age testing via saliva tests. I have not used any of these nor can I speak to their reliability.

I have though signed up for a test being developed by Dr. David Sinclair, one of the leading scientists in the longevity space. I would love to know my biological age!

Parting Thought

Health & wellness and longevity advice always seem to come back to diet and lifestyle. While the message might feel repetitive, I try and think of it as a reminder to make good choices when I can. To do what is better for me rather than what I might want to do. For example, this month I’m trying to moderate my alcohol intake by not having wine with dinner every night…baby steps!

See you next week…