In this article, researchers discuss the possible connections between the pathways associated with intermittent fasting, autophagy, and SARS-CoV-2 infection.  

Published in July 2020 in the journal Immunological Letters. The full article is freely-available online here:

REVIEW: Intermittent fasting, a possible priming tool for host defense against SARS-CoV-2 infection: Crosstalk among calorie restriction, autophagy and immune response

By Abdul Hannan, Ataur Rahman, Saidur Rahman, Abdullah Al Mamun Sohag, Raju Dash, Khandkar Shaharina Hossain, Mithila Farjana, and Jamal Uddin

Background Information:

• Vulnerability to COVID-19 is enhanced by pre-existing conditions and compromised immune systems 
• Deregulated immune responses result in immunopathology (immune response caused by a disease)
• Autophagy is a cellular response system that plays a key role in the regulation of innate and adaptive immunity
  • Innate immunity: nonspecific defense system you’re born with, protects your body against all antigens
  • Adaptive immunity: acquired and developed immunity conferred by antibodies and specialized cells. Induced by by exposure to pathogens.
• Fasting is connected to an increase in immune system function and activation of autophagy 

SARS-CoV-2 Immune Response:

• COVID-19 infection triggers a local immune response that causes macrophages and monocytes (white blood cells central to the immune system) to respond to the infection
• In the majority of cases, the immune response quickly subsides, and patients are able to recover
• But, in severe cases, a dysfunctional immune response leads to an immunopathological condition called a “cytokine storm”
  • Occurs when the immune system floods your bloodstream with inflammatory proteins known as cytokines
  • Consequences of a cytokine storm: fluid buildup in the lungs, respiratory distress and dysfunction, multi-organ failure.

Autophagy and Your Immune System:

• Autophagy is a specialized process that occurs inside cells to help balance and regulate cellular activities and components to ensure proper functioning
• Breakdown and recycling of dysfunctional, lethal, and mutant biomolecules, organelles, and pathogens
• Associated with cell survival, cell death, aging, and immunity
• Involved in the activation of the immune system in response to pathogens or infection.
• Within the innate immune system, autophagy functions to regulate activation, cell survival, cell division, and immune cell renewal.
• Encourages the release of antibodies and regulates the release of cytokines

Fasting and Autophagy:

• Autophagy triggered by periods of stress and starvation 
• mTOR is a cellular component that integrates information about nutrient levels, cellular environment, messages from other cells, and energy levels.
• During periods of fasting, mTOR acts as a positive regulator of autophagy 
• Fasting-induced autophagy can help by
  • Priming host immune system
  • Improving cellular resistance to stress

Fasting and Immune Responses:

• Intermittent fasting helps reduce inflammation, which can help which disease conditions that rely on inflammatory responses
  • Obesity
  • Asthma
  • Rheumatoid arthritis
• Upregulation of 
  • Metabolism
  • DNA repair
  • Immune system
• Reduction in fat mass, which can be achieved through intermittent fasting, is correlated with a decrease in cytokines

Significance:

• Without a perfect therapeutic treatment for COVID-19, it is important that we focus on preventative measures to prime our immune systems 
• Intermittent fasting can directly (by activating an immune response) or indirectly (by inducing autophagy) stimulate the body’s immune system and prime host defense systems to handle stress

Important Notes:

• This research is still extremely new, and we still need more information about it!
• The majority of the article discusses how the known pathways associated with autophagy, intermittent fasting, and SARS-CoV-2 might interact, but there has been no experimental research done to examine this relationship

Other Fasting Flamingo Autophagy Resources: 

• The Switch with James Clement- Ignite Your Metabolism with Intermittent Fasting & Keto
  • In this video, Reena Jadhav interviews author James Clement and discusses the metabolic benefits of intermittent fasting.  Specifically, they analyze some of the concepts present in Clement’s book, “The Switch,” which discusses the importance of the metabolic switch mTOR. 
• Alternate Day Fasting Improves Physiological and Molecular Markers of Aging in Healthy, Non-obese Humans
  • A comprehensive study of Alternate Day Fasting (ADF) in non-obese humans finds both promising longevity & weight loss results.
• Can autophagy (and fasting) naturally shed excess skin following weight loss? 
  • Is what you’ve heard true? Can autophagy help you naturally shed excess skin after weight loss?

Want to learn more?

• Read the original article here: https://pubmed.ncbi.nlm.nih.gov/32659267/
• Autophagy Wikipedia
  • Believe it or not, Wikipedia is a great starting place when learning about new scientific concepts! Just make sure to check the sources and follow up anything that interests you with more research.  
• Autophagy: cellular and molecular mechanisms