Autophagy is a process in which our cells remove all the accumulated junk and waste, like damaged DNA or proteins. This process shields cells from damage and helps them stay healthy. Autophagy can also help prolong lifespan and prevent many age-related diseases from happening.
Autophagy also offers cells a source of food in times of prolonged hunger. When we fast for at least 24 hours, we induce autophagy in cells and help them eat their parts quicker to survive. This process can also be induced by exercise and supplements like spermidine.
Do you want to learn more about autophagy for longevity, and how to induce it? Keep reading and learn more about autophagy!
What is autophagy?
Autophagy is a cellular process that "removes" all cellular debris, meaning all old and damaged cell parts. It's a way in which cells clean themselves, and it actually comes from the Greek words "autos" (self), and "phagomai" (eating).
The autophagy process allows cells to remove any old organelles, proteins, or membrane parts that don't function anymore. For example, the removal of old mitochondria is called mitophagy, and the removal of damaged lipids is called lipophagy.
In general, autophagy exists to:
- recycle and reuse old cell parts,
- destroy bacteria and viruses that are attacking the cell,
- get rid of non-usable cell parts.
How does autophagy happen?
Autophagy is carried on by many cell components, but primarily by autophagy-related proteins (ARPs), autophagosomes, and lysosomes. ARPs signal for the autophagosomes to form, and when they form, they carry the cell debris over to lysosomes.
Lysosomes are specific cell organelles that contain lysing enzymes, which can degrade almost anything, from faulty DNA to damaged proteins and lipids. Once the big structures have been degraded to components, cells can use those components as new building blocks or as food.
Autophagy increases under some specific conditions, like:
- infections by bacteria, viruses or other pathogens,
- prolonged hunger or starvation,
- cell damage.
If for some reason autophagy doesn't work anymore or it slows down, damaged cell parts which can't be removed anymore could cause problems for the cell. This could lead to cells not functioning well anymore, and accumulate damage to DNA and other important parts.
Does autophagy increase lifespan?
Studies done on animals like flies, worms, fish, rats, and mice, tell us that autophagy is increased in long-living organisms. When scientists increased autophagy in those lab animals on purpose, they discovered that the animals lived longer, were getting less sick, and overall had a much healthier and longer life.
Here is how autophagy contributes to longevity:
- it removes damaged and potentially dangerous cell parts,
- helps cells to maintain healthy and functional,
- prevents age-related diseases,
- offers a source of food in times of starvation or prolonged hunger,
- takes part in balancing cellular energy, especially under increased stress.
Unfortunately, as is the case with many cellular processes, autophagy decreases with age. That doesn't mean that our cells stop clearing out damaged parts, but they do so a bit slower. That also means that waste products and damaged cell parts stay in the cells a bit longer and can cause trouble.
A faulty or decreased process of autophagy has also been detected in the development of many diseases, such as:
- Alzheimer's disease,
- Huntington's disease,
- Parkinson's disease,
- Chron's disease,
- Diabetes.
Inducing autophagy, especially as we age, might be beneficial to prolonging our health and lifespan (1).
Some other molecular processes and pathways have been linked to longevity, such as the mTOR and the AMPK pathways. You can read more about them here: Are AMPK and mTOR pathways the molecular key to longevity?
Autophagy and longevity in humans
When it comes to autophagy and anti-aging in humans, there aren't as many scientific studies as those performed on lab animals. The reason is mostly that it's very difficult to induce autophagy in the way it's induced in animal subjects.
However, there are multiple substances (or rather functional dietary supplements) that were scientifically proven to induce autophagy. In some cases, those were also used in human studies to induce and follow the effects of autophagy through time.
Here are the supplements and substances that induce autophagy:
- spermidine,
- resveratrol,
- curcumin,
- urolithin A,
- tomatidine.
Out of these, spermidine and resveratrol were tested in human clinical studies.
Autophagy - studies in humans
Spermidine has been long known and proven as an autophagy inductor, especially in yeast, flies, worms, and mice. This naturally occurring polyamine has then also been tested in a grand human clinical study on more than 800 participants.
