What Is Autophagy?

Autophagy is a natural process by which a cell breaks down old, damaged, unnecessary, or dysfunctional components within a cell and then repurposes those components for fuel and to build or maintain cells.

Autophagy is important as these "junk" components take up a lot of room in a cell and can prevent it from working properly. Autophagy also destroys disease-causing pathogens, like bacteria and viruses, that can harm cells.

This article describes how autophagy works, what triggers the process, and the medical significance of autophagy in diseases like Parkinson's disease and Crohn's disease.

How Autophagy Works

Autophagy takes place within the gelatinous fluid inside of a cell called cytoplasm. It is a process in which a cell recycles unneeded or damaged parts of itself to create new parts and to provide energy for cell survival.

Autophagy occurs when cells are either damaged or deprived of the nutrients that they need to survive. When this happens, complex chemical reactions are triggered within the cytoplasm to turn "junk" into fuel and functional cell components.

The process involves four steps:

1. Sequestration: This occurs when a dysfunctional component of a cell is surrounded by a double-membrane structure called a phagophore. The encased component is called an autophagosome.
2. Transfer: This takes place when the autophagosome is fused to a specialized structure in the cytoplasm, called a lysosome. Lysosomes contain enzymes that degrade dysfunctional components.
3. Degradation: This happens when a lysosome releases enzymes called hydrolases that break down the dysfunctional component into amino acids (the building block of proteins).
4. Utilization: During this phase, amino acids are repurposed as a fuel source for cells, called adenosine triphosphate (ATP), and synthesized into new proteins to maintain cells, rebuild cells, or create new cells.

With autophagy, a cell effectively breaks itself down and rebuilds itself in order to survive. By doing so, a cell becomes more efficient.

Benefits of Autophagy

Autophagy has important effects that occur both within and outside of a cell.

Within the cell, autophagy can help:

• Decrease oxidative stress (damage to cells caused by unstable molecules known as free radicals)
• Keep DNA and genes stable
• Avoid the premature deterioration and aging of cells
• Improve conversion of nutrients into energy
• Improve the elimination of waste
• Eliminate pathogens and other foreign materials within cells

Outside of the cell, autophagy can help:

• Decrease inflammation
• Improve the transmission of nerve signals in the brain
• Keep the immune system functioning normally
• Support detection of cancer and other foreign agents by the immune system
  

Can You Trigger Autophagy?

Autophagy is typically triggered when a cell is starved of nutrition and goes into survival mode. This can happen with:

• Fasting: Depriving the body of nutrition forces cells to repurpose cell components into ATP for fuel.
• Exercise: Exercise quickly burns glucose (the body's main source of energy), triggering autophagy to keep cells functioning.
• Restricting calories: Autophagy compensates for the loss of nutrients due to consuming too few calories.
• Switching to a keto diet: Embarking on a high-fat, low-carb triggers autophagy when your body burns fat instead of glucose.

This doesn't mean that you should try to induce autophagy to keep yourself healthier. The aim of autophagy ultimately is to keep the body in homeostasis.

Making sudden, severe changes to your diet or exercise routine can cause more harm than good. This is especially true if you are pregnant, breastfeeding, or managing a chronic condition like diabetes, heart disease, or high blood pressure.

Significance in Medicine

Autophagy declines with age, contributing to the aging process. Oxidative stress, DNA damage, ultraviolet radiation, and a person's genetics can also disrupt autophagy, contributing to the development of certain chronic illnesses.

Studies have shown that autophagy dysfunction is associated with diseases like:

• Amyotrophic lateral sclerosis (ALS)
• Alzheimer's disease
• Autoimmune diseases
• Cancer
• Chronic kidney disease
• Crohn’s disease
• Diabetes
• Heart disease
• Huntington's disease
  
• Liver disease
• Parkinson's disease

Even so, the relationship between autophagy and diseases like these isn't clear-cut. While scientists are hoping to find ways to induce certain facets of autophagy to treat neurodegenerative diseases like Parkinson's or even cancer, the research remains in its infancy.

There is currently no evidence that you can alter or prevent disease by inducing autophagy. or that triggering autophagy is a reasonable health and wellness strategy.

Summary

Autophagy is a process that keeps your body's cells in proper balance by taking old or damaged components in a cell and recycling them. The recycled parts are turned into amino acids that can be used for fuel or to form new proteins.

Autophagy is triggered when the body is starved of energy, such as can occur with exercise, calorie restriction, fasting, or a keto diet.

Certain chronic diseases are linked to problems with autophagy. Even so, there is no evidence that triggering autophagy with diet or exercise can prevent or treat illnesses. Exercise and diet may be of benefit to you, but not for the purpose of inducing autophagy.