The effect of caloric restriction (CR) on the immune system in laboratory animals is a topic that has sparked numerous studies and debates. Laboratory animals are kept in a specific pathogen-free environment, so they are not exposed to all the challenges humans face. Thus, one question is whether animals on CR are immunocompromised. The data in this regard is mixed, but some studies have shown that CR animals respond better to pathogen challenges than ad libitum-fed control animals. However, CR animals may experience immune deficits for certain types of challenges. For instance, sepsis experiments have shown that CR animals die much more quickly than controls when inducing sepsis in them. This suggests that CR could impair human immune function and lead to a higher risk of infectious diseases.
Another complication when discussing CR is the question of optimal CR with optimal nutrition. In laboratory settings, researchers can control all aspects of nutrition to ensure that animals on CR have all the necessary nutrients and vitamins. However, in real-world settings, it is challenging to do this, and individuals who practice CR may not get all the necessary nutrients to maintain a functioning immune system. This becomes even more concerning if CR is recommended to the general public based on mouse studies alone. The environmental complexity that humans live in and genetic complexity make it challenging to extrapolate to humans.
Studies have also shown that most functional measures of aging, such as Frailty and sarcopenia, seem to be preserved in calorically restricted animals. However, the issue of body composition becomes particularly complex in the case of CR. For instance, studies may normalize muscle function to body weight, which means that calorically restricted mice have maintained muscle function proportionate to their body weight. However, this raises the question of whether it’s a good or bad thing if someone loses 30% of their body weight and 30% of their strength. While it may be better than the starting point, it’s not optimal. Optimal weight loss may be when an individual loses 30% of their body weight but disproportionately loses adipose tissue and only a tiny percentage of their strength.
When it comes to humans, a study has shown that the difference in bone mineral density in people who undergo equal amounts of weight loss, one driven by CR and the other by exercise, is that the exercise-driven weight loss group did not experience a reduction in bone mineral density, but the CR group did. This suggests that other factors may be at play and that CR may not be the right tool for longevity once optimal weight is achieved.
In conclusion, while CR may positively affect the immune system, it’s a complex topic, and the data is mixed. Additionally, the issue of optimal CR with optimal nutrition becomes particularly challenging in the real world, where individuals may not get all the necessary nutrients. It’s important to consider all these factors and not recommend CR based on mouse studies alone. Instead, optimal weight loss should be the goal, and other strategies, such as exercise, should be considered.
*****
*****
Summary of Transcript:
The effect of calorie restriction (CR) on the immune system in laboratory animals is complicated because animals in the lab are in a low-pathogen environment. Studies have shown that CR animals respond better to pathogen challenges but are deficient in specific challenges like sepsis. CR with optimal nutrition does not compromise immune function, but CR without optimal nutrition may lead to immune deficits due to a lack of micronutrients. Functional measures of aging, like Frailty and sarcopenia, are preserved in calorically restricted animals. Still, it’s important to note that muscle function is normalized to weight, and calorically restricted mice weigh substantially less than ad libitum-fed mice. The CR group experienced a reduction in bone mineral density, whereas the exercise-driven weight loss group did not. It is unclear if CR is the right tool for longevity once optimal weight is achieved.
*****
Summary of Description:
This clip is from episode #222 of The Drive featuring Dr. Matt Kaeberlein, a globally recognized expert on the biology of aging. The discussion revolves around the effect of caloric restriction on the immune system, strength, muscle mass, and Frailty in laboratory animals and whether additional caloric restriction benefits longevity once optimal weight is achieved. The Peter Attia Drive is a podcast focused on maximizing longevity, covering exercise, nutritional biochemistry, cardiovascular disease, Alzheimer’s disease, cancer, mental health, and more. The podcast is hosted by Peter Attia, founder of Early Medical, a medical practice applying the principles of Medicine 3.0 to lengthen lifespan while improving healthspan.
*****
Source Description
Get the 5 Tactics in My Longevity Toolkit and my weekly newsletter here (free): https://bit.ly/42sUBWq.
Become a member to receive exclusive content: https://bit.ly/3O0pEnY
Watch the full episode: https://youtu.be/4sqyGwqyAao
This clip is from episode #222 of The Drive – How nutrition impacts longevity | Matt Kaeberlein, Ph.D.
In this episode, Peter is joined by Dr. Matt Kaeberlein, a globally recognized expert on the biology of aging and recurring on The Drive.
In this clip, we discuss the following:
– What do we know about the effect of caloric restriction on the immune system of laboratory animals?
– How does caloric restriction affect strength and muscle mass?
– How does an animal’s frailty (sarcopenia) change in a caloric-restriction environment?
– Once you achieve optimal weight, is additional caloric restriction beneficial for longevity?
——–
About:
The Peter Attia Drive is a deep-dive podcast focusing on maximizing longevity and all that goes into that, from physical to cognitive to emotional health. With over 60 million episodes downloaded, it features topics including exercise, nutritional biochemistry, cardiovascular disease, Alzheimer’s disease, cancer, mental health, and more.
Peter Attia is the founder of Early Medical. This medical practice applies the principles of Medicine 3.0 to patients to lengthen their lifespan and simultaneously improve their healthspan.
Learn more: https://peterattiamd.com.
Connect with Peter on:
Facebook: http://bit.ly/PeterAttiaMDFB
Twitter: http://bit.ly/PeterAttiaMDTW
Instagram: http://bit.ly/PeterAttiaMDIG
Subscribe to The Drive:
Apple Podcast: http://bit.ly/TheDriveApplePodcasts
Overcast: http://bit.ly/TheDriveOvercast
Spotify: http://bit.ly/TheDriveSpotify
Google Podcasts: http://bit.ly/TheDriveGoogle
Disclaimer: This podcast is for general informational purposes only and does not constitute the practice of medicine, nursing, or other professional healthcare services, including the giving of medical advice. No doctor-patient relationship is formed. Using this information and the materials linked to this podcast is at the user’s risk. The content on this podcast is not intended to substitute for professional medical advice, diagnosis, or treatment. Users should not disregard or delay in obtaining medical advice for any medical condition they have, and they should seek the assistance of their healthcare professionals for any such conditions. I take conflicts of interest very seriously. For all of my disclosures and the companies I invest in or advise, please visit my website, where I keep an up-to-date and active list of such companies. For a complete list of our registered and unregistered trademarks, trade names, and service marks, please review our Terms of Use: https://peterattiamd.com/terms-of-use/
