Do my cells have a different birthday?

What really is aging?

If you haven’t already, it may be beneficial to read Post 1 to learn more about Live Longer World and Post 2 to learn about your teachers Molly & Doug before reading this post.

xxx

Molly: Happy birthday, Doug!

Doug: Thanks Molly! I can’t believe how old we are getting. My hair will soon start turning white.

Molly: Not so soon, Doug. Not if you listen to me.

Doug: Uhh, alright alright, not another longevity rant. Not on my birthday at least.

Molly: Well, okay then I’ll give in this time around. I have a present for you!

Doug: Gee, thanks, what do we have in here? A biological age test? What does that even mean?

Molly: This is your chance to really see how soon your hair will start turning white!

Doug: Great, thanks for the brilliant explanation. It makes so much sense! Fiine, you can go on your rant. I may as well understand this if I can prevent white hairs.

Molly: You see, there is a high chance that there is a difference in the age you tell other people versus your body’s internal system of tracking age. 

Doug: Okay..

Molly: Think of it as external age and internal age. Now, the external age is the age you tell other people. For you, you turned 28 today and that means 28 years since you were born. That’s your external age or in more correct parlance, you’d call it chronological age.

Doug: Sure, I get that. You know I’m not 5 anymore that you’re explaining counting to me.

Molly: Here’s the fun part. Did you ever think that your body might be running its own aging clock? Regardless of the external age you tell people, the body has its own tracking mechanism to determine your internal age.

Doug: You mean, it’s possible for my external age to not match my internal age?

Molly: Bingo! And this internal age is your biological age. The present I got you is going to detect your biological age using your DNA sample.

Doug: Woah, let’s take a step back! Why might there be a discrepancy between this..umm..chronological age and biological age?

Molly: Great question, thanks for asking, Doug! Seems like your brain might be sharper than an aging 28 year old’s! 

Doug: Hey! Let me remind you, it’s still my birthday!

Molly: Alright, jokes apart. Before I talk about why the discrepancy might exist, let me briefly explain what biological aging is. Biological aging is the rate at which your cells are aging. As you know, our body is made up of trillions of cells. Every organ and tissue is ultimately made up of cells. This is why we call cells the building blocks. Ooo..what if we thought of cells as lego blocks?

Doug: Suureee..umm Molly you’re not really good at jokes if that was supposed to be one.

Molly: Cells have their own internal clock that is regulated by genetics as well as lifestyle factors. In fact, as we grow up, cell division and replication stops. But cell senescence increases. 

Doug: Cell sen-what?

Molly: Cell senescence¹. It occurs when cells lose their ability to divide. In addition, they become resistant to death and accumulate with age. It’s like a rotten tomato that can’t be eaten but will refuse to be thrown out of the bowl. And this is when problems start to occur. (To be fair, senescent cells do have some useful functions like tissue and wound healing but we won’t go into that for now.)

Molly: So cellular senescence is happening all the time and it increases with age. And as I said, these “rotten” cells refuse to die and can accumulate in the body. When they don’t get cleared away, they release pro-inflammatory cytokines (harmful substances) and damage the cells around them too. Think of that one rotten tomato causing the other tomatoes to become rotten too because of the nasty juices it releases.

Doug: Okay, and what does this have to do with aging?

Molly: Ah, yes I’m getting there. As these senescent cells accumulate, they cause inflammation.² Inflammation is your body’s process of fighting against things that harm it, by activating the immune system. While low-level inflammation helps in the healing process, too much inflammation can lead to chronic inflammation in which the body’s immune system starts attacking itself. As a result, chronic inflammation is studied to be the single most important factor in the aging process. So much so that scientists have coined the term Inflammaging, meaning aging due to inflammation. 

Doug: Hmm..I see..so it sounds like the cause of inflammaging are these sen cells? I’m just going to call them sen cells, btw. Is there a way to clear away these sen cells so they don’t accumulate?

Molly: Very smart, Doug! Yes, there is and it’s a process called autophagy...

Doug: Wow! This is blowing my mind. 

Molly: Not so fast, Doug. You have perhaps forgotten to ask me one question. You have assumed that cellular senescence is inevitable, which is true. But it seems like you’ve also assumed that the rate of senescence might be constant and the same for every individual, which is far from true. Have you wondered why some people have an earlier onset of diseases such as cancer compared to others? 

Doug: So cancer is not just bad luck? It’s part of the aging process that can be detected?

Molly: That’s right. Among other factors including genetics, one of the reasons age-related diseases such as cancer can occur is because of the accumulation of these sen cells. This begs the question: what causes a cell to be senescent? [Because remember that senescent cells increase with age.]

Molly: Cellular senescence is affected by a primary factor: DNA damage.³ There are other factors that play a role such as telomere shortening, but supposedly the central role in the aging process is due to DNA damage.

Doug: Telomuh what? Gosh Molly, is this beginning to get more complicated?

Molly: Not at all! It’s the fun part. Bear with me, I’m making it as simple as I can for you, so we will only focus on DNA damage for now. 

Doug: Yeah thanks, I get it. It is rather fascinating.

Molly: Damage to your DNA has molecular consequences⁴ such as dysfunctional mitochondria, unstable genome and epigenetic alterations and these can result in cellular senescence which results in aging.

Doug: Okay my head is spinning...can you just explain what the point is?

Molly: Yes sorry..the gist is that lifestyle factors can play a huge role in DNA damage! Poor diet, alcohol and drug use, poor quality sleep, obesity, UV rays, other chemicals etc. can accelerate DNA damage. Yes, it’s rather sad. But here is the real fun part. It works in the opposite direction too! Good lifestyle choices including proper micronutrients in your food, regular exercise, quality sleep can reverse some of the damage, and in turn, reverse aging!⁵ Isn’t that cool??

Doug: Woah hold up! This is beginning to make sense. DNA damage causes cells to be senescent which in turn causes inflammaging. And now you’re telling me that DNA damage can actually be controlled to some extent by making certain lifestyle choices that are also backed by science. Sooo...if I followed these lifestyle protocols, I could live to be a 100?!

Molly: Well yes that could very well turn out to be true! If not older than a 100! Either way, it will certainly improve the quality of your health and hopefully delay the onset of some of the age-related diseases.

Doug: And being the darling girlfriend that you are, you will educate me on these lifestyle protocols that are backed by science?

Molly: Haha, that’s clever of you, Doug. Fine, for each year of your life that I give back to you, you have to dance to Backstreet Boys 5x. We can do regular biological age tests to determine.

Doug: Oh Molly, not the Backstreet Boys challenge again!

Molly: You better get your dance moves ready, Doug! I will educate you and help you improve your lifestyle choices. Make sure to subscribe to my newsletter and you will receive practical and easy to implement tips and tricks that go towards reversing aging and improving health. 

Molly: And Doug, since you complain that I’m boring, I’ll try to make longevity science fun by adding some stories and some not-so-artistic wobbly sketches. At least I hope to be a cool nerd.

Doug: Oh Molly, you know I pull your leg - you’re such a fun nerd!

(Note: I did get a biological age test done a few months ago (April 2021) and it turns out my biological age is 24 which is 2 years younger than my chronological age. This translates to a rate of aging of 0.92. However, note that your biological age changes based on your lifestyle and other factors, and it is best to get tested periodically should you wish to do so.)

1. https://www.nature.com/articles/nrm2233

2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4166529/

3. https://www.nature.com/articles/s41586-021-03307-7

4. https://www.nature.com/articles/s41586-021-03307-7

5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8064200/