Priscilla Xu

Reading Time: 5 mins

Have you watched a movie called Alita: Battle Angel? Having a human brain attached to a robot body to live forever might be possible in human history. Before cyborgs, we’ll see how, “in theory,” we can live forever. I went out into the wild internet to understand the theories of aging.

David Sinclair is a biologist at Harvard. He is well known for specializing in aging and epigenetics. In his lab, Sinclair can measure the biological aging clock of yeast and mice. As a result, animals can live significantly longer than the average lifespan.

Why you can live forever, in theory?

In Sinclair’s book Lifespan, he proposes the information theory of aging.

“Aging, quite simply, is a loss of information.” in the cells to function

David Sinclair

But what does the sentence mean?

Everything on you, such as your skin, hair, eye color, and nails, is made of proteins. So how does the human body produce protein? To understand David Sinclair’s theory of aging, we’ll go back to the basics. The central dogma of biology is the model of how genetic material is transcribed into proteins in living organisms.

DNA stands for Deoxyribonucleic Acid, and its shape is a double helix. The “bars” in the ladders are the codes. The “bars” are called nucleotides. The four types of nucleotides are adenine (A), cytosine (C), guanine (G), and thymine (T).

The ACTG codes for the protein in your body. The central dogma has two processes: transcription and translation. First, the DNA is transcribed into RNA. Then, RNA is translated into protein.

In a healthily functioning body, the neuron will produce proteins for being a neuron, and a muscle cell will do its jobs. Aging starts when the cells are confused with their identity. Cells become problematic when the central dogma starts producing proteins that it is not supposed to. Sinclair theorizes that all diseases are based on cells losing their identity. For example, Alzheimer’s is a brain cell not knowing how to be a brain cell because of incorrectly produced proteins.

So, if you are can reverse your biological age every year when you grow one year older on earth, you can technically live forever.

The excellent news is that the speed of aging is 80% in your control and 20% determined by genetics.

How to measure how old you are?

So, how can you know how old you are?

The first is counting the number of candles on your birthday cake. Chronological age is the number of earth years you have lived. Furthermore, biological age is your cell’s age.

The entire DNA chain in humans is around 2 meters long, and it needs to be packed into your cells that are about 0.1mm to 0.0001mm in diameter. The DNA is wrapped around globular proteins called histones.

During the transcription process, not the entire 2-meter strand of DNA will be used to produce proteins for a specific cell type. Instead, they used DNA is turned on by DNA methylation, adding methyl groups (-CH3) to DNA. DNA methylation controls how much a gene is expressed (meaning the manual is read to make proteins). If a cell does not know what genes to turn on, it can slowly lose its identity.

If the DNA is not controlled correctly by methylation, the DNA expression can be changed and lead to diseases like cancer.

Biologist Steve Horvath’s lab is developing a biological clock to determine every type of mammalian cell’s age by measuring the methylation process.

The Longevity Proteins

There are groups of proteins that help maintain the information accuracy in our genetic survival kit.

• AMPK stands for AMP-activated protein kinase. It is an enzyme activated when your body does not have enough ATP energy. When activated, the cell breaks down glucose and fatty acid to restore energy levels and switch off cells’ growth pathways for anti-aging
• NAD is nicotinamide adenine dinucleotide. The amount of NAD declines with aging, so the goal is to increase the number of NAD.
• Sirtuins are metabolic regulators for cell health. The regulators are found in every organism. Seven sirtuins are related to aging and DNA repair. The proteins are only active when NAD is also available.
• mTOR stands for mammalian target of rapamycin. This protein is found in every organism too. mTor digests old protein and signals DNA repair.

How do we slow down aging?

Here’s the premise of slowing down aging.

Humans do not know when the next meal will be in the scavenger and hunters era. However, humans live in an age of abundance nowadays, and there is pretty much no biological stress.

When the body is under biological stress, the longevity genes are activated, and aging is delayed. However, too much stress or overwork leads to aging.

Paraphrased from Lifespan

This is known as adversity mimetics — factors that simulate biological adversity.

Those are some tips that I have learned from reading the Lifespan book and listening to Dr.Sinclair’s podcast. However, please note that I am not a licensed medical doctor. Please consult your physicians fr your health needs.

• As David Sinclair says in his podcast, get off your ass. Simple things such as
  • Take a walk after you eat.
  • Vigorous exercise 3 times per week. Vigorous activity means increasing your heart rate and breathing for a minimum of 10 minutes because low oxygen in the body stimulates the growth of blood vessels and increases NAD levels.
• Cold showers. Cold temperatures turn on the body’s pathway for producing brown fats, linked to aging issues.
• Intermittent fasting. This tells your body that it is under biological adversity.
• Low protein, high vegetable diet. According to the Lifespan podcast’s episode on eating to stay young, Sinclair suggests decreasing the number of amino acids from the meat will block mTOR from functioning. If mTOR is inhibited, mitochondria are not repaired as much.

Side note: I wrote this article as synthesis/understanding of the theories that Dr.David SInclair says about again. Feel free to correct me if I misinterpret the idea. This is the beauty of learning in public XD.