My wife and I have recently started watching the new Netflix series Down to Earth with Zac Efron after many recommendations from our friends. I have personally enjoyed learning how various cultures live and the way they utilize the resources provided to them in their environment.

While I have learned a lot, I wanted to discuss something Zac and Darin (series co-host) “learn” while visiting the Blue Zones of Sardinia. For those who are unfamiliar with a Blue Zone, the term was coined by Dan Buettner, Michel Poulain, and Gianni Pes (who appears in the Sardinia episode). These are places around the world where people have higher than average life expectancy. 

We will not discuss Blue Zones today, but instead, I wanted to look at three studies, I know, three studies seems like a lot, but I will do my best to keep it brief, as I believe this is an important topic to cover. 

In Episode 4 (Sardinia), Zac and Darin visit Valter Longo, a biogerontologist and cell biologist who specializes in longevity. Valter Longo shares on the show that the centenarians (one who is 100 years or older) of Sardinia eat a low protein diet. Longo highlights the findings from a study he participated in with Levine et al. in 2014, which showed a high-protein diet was associated with a 4-fold increase in cancer mortality. 

That sounds pretty serious, right? What they do not mention in the episode is the same study found higher protein intakes were associated with a decreased risk of cancer and overall mortality. 

How does this make sense? Well, according to the researchers, those who are between 50 to 65 years of age should consume a low-protein diet, but eat a high-protein diet once you are over 65 years of age. Again, how can this be the case? How can protein be “bad” during a specific age range, yet beneficial at another? As Dr. Paul Saladino has mentioned, this appears to be an “artifact of epidemiology.” Epidemiological studies can offer value and insight; however, they cannot prove cause and effect, but instead, just associations. As you can see, the claims Longo makes in the Sardinia Episode are incomplete, and he omits a valuable piece of the research. Let’s look at the mechanism Longo is concerned about with regards to protein. 

Their concern with protein is due to proteins signaling of mTOR (mammalian target of rapamycin) and IGF-1 (insulin-like growth factor-1). Diving into mTOR and IGF-1 would take some time, so instead, I will share what stimulates both of these compounds/molecules. 

mTOR is stimulated by IGF-1, insulin, protein (primarily through the amino acid leucine), and exercise. Insulin is released in response to consuming carbohydrates and protein; however, carbohydrate intake results in a more pronounced insulin response. IGF-1 is produced as a result of growth hormone secretion, which occurs with eating, sleep, and exercise. 

I mention all of this to point out that limiting protein is just one component that stimulates this growth response via mTOR. 

The last two studies I want to mention make a case against the recommendations made by Levine et al., the paper that Longo references in the episode. Both studies, published in 2018, highlight the importance of dietary protein in preventing sarcopenia (muscle wasting). Sarcopenia, which I have discussed before, is associated with multiple adverse health outcomes, which include falls and fractures, decreased mobility, depression, poor quality of life, hospitalization, and mortality.

I know this information may be confusing, and I plan on dedicating more time to unpacking it, but what I want you to walk away with is: Protein is not bad. I do believe we do not want to over-stimulate mTOR, but, as we discussed, our protein intake is just one of the ways it is triggered. Protein is essential for preserving and building muscle mass, which is associated with improved longevity and health. What is the point of living a long time if you cannot move and do the things you enjoy?

I hope you found this information interesting. If you have questions or suggestions for topics you would like me to cover please do not hesitate to reach out!

That’s all for now!