Autophagy

Cells are the building blocks of life, each containing multiple parts that keep them functioning. Over time, however, parts of the cell can become defective, stop working, and become “junk” inside of an otherwise healthy cell.

Autophagy is a stress response in the body that plays the essential quality control function of removing accumulated junk and thereby rejuvenating cells. Because autophagy is the process by which cells clean themselves out, autophagy is essential to survival, development, and homeostasis. 

How do you pronounce autophagy?

Autophagy (pronounced “ah-TAH-fah-gee”) is the combination of the Greek words for self, “auto,” and to eat, “phagy.” Together, they mean eating of self.

This term was first coined by Christian de Duve in 1963. When the process was first discovered, however, scientists didn’t quite understand why cells would self-digest their own components. 

Now, scientists recognize that autophagy is more than just the cell’s way of removing cell junk— intracellular misfolded or long-lived proteins, superfluous or damaged organelles, and invading microorganisms. 

Autophagy, or this process of removing this cell waste, is “an adaptive response to provide nutrients and energy on exposure to various stresses.” 

If cellular junk isn’t removed and instead continues to accumulate, the waste can permanently alter the cell’s genes and make it impossible for the cell to repair itself. The functioning of autophagy has implications for cancer, neurodegeneration, immune response, development and aging.  

Can fasting cause autophagy?

Autophagy typically happens during quality sleep (assuming we don’t have a big meal before bed). It is a normal cell maintenance function that seeks to rid the body of autophagosomes, materials slated for removal by autophagy, accumulated during the wakefulness of the day. 

Fasting can also initiate autophagy. A 2014 study first demonstrated that fasting triggered a natural, stem-cell based regeneration in which cells transitioned from a dormant state to one of self-renewal. By fasting, you deprive your body of nutrients for a period, forcing your cells to repurpose cell components to function.

How long do you need to fast to initiate autophagy?

Fasting-induced autophagy could have a significant impact. In a 2017 study, fasting in mice and humans over the course of four days provoked major changes in the plasma metabolome that make up a cell. 

While there haven’t been many studies on fasting and autophagy in humans, a 2019 study on time-restricted feeding, a form of intermittent fasting, suggests that autophagy begins at 18-hours of fasting.  

Calorie restriction to modulate autophagy in combination with other anticancer therapies may be a promising protocol for cancer therapy in the future. 

Can autophagy firm loose skin?

Autophagy can promote firmer skin. Cells in our connective tissue make collagen, or the protein molecules that provide structural support for skin, tendons, bones, and ligaments. 

As we age, waste builds up in cells, sometimes preventing the production of collagen and leading to wrinkles and loose skin. (Loose skin can also be the result of losing extra weight.)

In a 2017 study, when treated with an inhibitor of autophagic flux, collagen deposition increased. Because autophagy cleans up the cellular waste, thereby increasing collagen production, it can naturally firm up the skin.