Welcome back to our regular feature where we sift through thousands of new, health-related papers, and pick a few to summarize in a practical and not anxiety-inducing way.
Our main questions on each paper:
- In simple language, what does it say?
- Does it have good evidence?
- Should what it says matter to normal people?
- What simple thing, if anything, could a normal person do to take advantage of this finding?
Okay, away we go. And, as always, we rate each paper for practicality and level of interest.
This edition's articles and papers:
- 8-hour time-restricted eating linked to a 91% higher risk of cardiovascular death, American Heart Association, 2024
- Tokizane, K., Brace, C. S., & Imai, S. (2024). DMHPpp1r17 neurons regulate aging and lifespan in mice through hypothalamic-adipose inter-tissue communication. Cell Metabolism, 36(2), 377-392.e11. https://doi.org/10.1016/j.cmet.2023.12.011
- Garza, M. C., Antonia, M., & Jarauta, E. (2024). Effect of Aromatic Herbs and Spices Present in the Mediterranean Diet on the Glycemic Profile in Type 2 Diabetes Subjects: A Systematic Review and Meta-Analysis. Nutrients, 16(6), 756. https://doi.org/10.3390/nu16060756
- Baker, L. M., Yawar, A., Lieberman, D. E., & Walsh, C. J. (2024). Predicting overstriding with wearable IMUs during treadmill and overground running. Scientific Reports, 14(1), 1-10. https://doi.org/10.1038/s41598-024-56888-4
Now, here are our quick takes on the papers:
Paper: 8-hour time-restricted eating linked to a 91% higher risk of cardiovascular death
We'll summarize the paper first in the usual way, and then critique it in more detail afterward.
Practicality (5/5): 🏃♂️🏃♂️🏃♂️🏃♂️🏃♂️
Interest (4/5): 🏃♂️🏃♂️🏃♂️🏃♂️🏃♂️
Summary
A large study indicated that adults who ate all their food within an 8-hour period each day had a significantly higher risk of dying from heart disease compared to those who spread their eating over 12 to 16 hours. This is called 16:8 intermittent fasting, and the findings suggest people should be cautious when considering time-restricted eating as a dietary choice.
What is the paper's main claim?
- The central claim of the study is that consuming food within a restricted 8-hour window may heighten the risk of cardiovascular mortality, challenging popular intermittent fasting.
Are the methods and/or data it uses appropriate and convincing?
- The study analyzed dietary patterns from substantial survey data (over 20,000 adults) against death records, making the findings relevant for a large population,
- Relied on self-reported data.
- Effect size is noteworthy (91% increase in risk), but the study does not establish causation
- Other health variables not included in the analysis may confound the findings.
What do we know now that we didn't know before, if anything?
- There is now evidence to suggest potential long-term cardiovascular risks associated with time-restricted eating, which was previously promoted for its benefits on metabolic health.
What simple and practical thing could a normal person do knowing this?
- In theory you could avoid intermittent fasting and eat more regularly, but that is also associated with a higher risk of cardiovascular diseases, so that doesn't leave much.
Detailed Critique
Critically evaluating the study, there are various potential confounds and limitations:
- Self-Reported Data: The study relies on self-reported dietary information. This is a huge problem, given that people are terrible at remembering what they ate, or when.
- Short Dietary Assessment Window: Slotting people into different time-restricted eating windows was based on just two days of dietary intake, which is not a representative sample of dietary intake.
- Lack of Control for Confounding Variables: The analysis did not account for other factors that may affect health outcomes, such as physical activity levels, sleep patterns, and socioeconomic status. Were some of these people dramatically more sedentary? We don't know. Were there results skewed by over-indexing on people who were only fasting because they lacked access to adequate food? We don't know.
- Nutrient Quality Not Assessed: The study did not provide information on the nutrient quality of the participants' diets. What people eats matters more than when they eat.
- Causality versus Association: The study identified an association between an 8-hour eating window and increased cardiovascular mortality, but this does not establish a causal relationship.
- Study Design: There was no information provided on the study design. We don't know if it was prospective, retrospective, or something else. Without knowing that the strength of the evidence cannot be assessed.
- Single-study Problem: This is a single study, a flawed one, and one without good data on methods or design. A single study does not invalidate the preponderance of evidence showing that restricted eating has broad positive health effects.
In short, how seriously should you take this claim? Not very seriously. It is preliminary, flawed, and would require much more careful work and more confirmatory studies.
Paper: Brain Neurons Control Aging
Practicality (5/5): 🏃♂️
Interest (4/5): 🏃♂️🏃♂️🏃♂️🏃♂️
Summary
Researchers discovered a group of brain cells in mice that help slow down the aging process by communicating with fat tissue. These cells, found in a brain region called the dorsomedial hypothalamus, stay active when things are working well. But as mice get older, these cells become less active. By keeping these cells working, aging symptoms in mice, like decrease in physical activity and less efficient fat metabolism, were reduced and their lifespans were extended.
What is the paper's main claim?
- Key brain cells in the dorsomedial hypothalamus influence aging by managing fat tissue functions and preventing age-related decline.
Are the methods and/or data it uses appropriate and convincing?
- The experiments used a variety of methods, including genetic techniques, to show how these brain cells affect aging in mice.
What do we know now that we didn't know before, if anything?
- Specific neurons in the hypothalamus play a critical role in the aging process and longevity by managing key pieces of the body's metabolic machinery.
What simple and practical thing could a normal person do knowing this?
- Nothing, but it does show the increasing progress being made in understanding the manipulable mechanics of human aging
Paper: Spices Impact on Diabetic Health
Practicality (5/5): 🏃♂️🏃♂️🏃♂️🏃♂️🏃♂️
Interest (4/5): 🏃♂️🏃♂️🏃♂️🏃♂️
Summary
This study examined how certain spices and herbs commonly found in the Mediterranean diet affect blood sugar levels in people with Type 2 Diabetes. It analyzed a number of studies and found that cinnamon, turmeric, ginger, black cumin, and saffron can significantly lower fasting glucose levels. Specifically, ginger and black cumin also helped improve long-term blood sugar control, while cinnamon and ginger reduced insulin levels.
What is the paper's main claim?
- Substances like cinnamon, turmeric, ginger, black cumin, and saffron may help manage blood sugar in Type 2 Diabetes patients.
- Ginger stands out for its broad impact on fasting glucose, long-term blood sugar control, and insulin levels.
Are the methods and/or data it uses appropriate and convincing?
- Studies reviewed varied widely in design, sample size, and duration, which influences the reliability of their conclusions.
- The effect size is notable, especially for black cumin in fasting glucose reduction, but differences in research methodologies call for cautious interpretation of the results.
What do we know now that we didn't know before, if anything?
- There is substantial evidence supporting the use of specific spices and herbs in managing blood sugar levels in diabetic individuals.
- The novelty lies in the detailed synthesis of existing research and highlights ginger as particularly effective.
What simple and practical thing could a normal person do knowing this?
- Consider incorporating ginger and black cumin into your diet, especially if you are pre-diabetic or managing Type 2 Diabetes.
Paper: Running Injuries and Over-Striding
Practicality (5/5): 🏃♂️🏃♂️🏃♂️
Interest (4/5): 🏃♂️🏃♂️🏃♂️
Summary
Overstriding—when the foot lands too far in front of the center of mass—is a common cause of running injuries. The researchers found that IMUs can reasonably assess the angle of runners' limbs and, consequently, the degree of overstriding, potentially offering a practical tool for injury prevention and performance improvement, one usable outside of labs.
What is the paper's main claim?
- The research validates the use of wearable devices for measuring overstriding—the distance the foot lands in front of the runner's center-of-mass—outside of laboratory conditions.
- It argues that their method can predict overstriding, which is a known factor in running-related injuries.
Are the methods and/or data it uses appropriate and convincing?
- The study includes ten runners, a reasonable sample size for initial validation, but larger studies are necessary to generalize findings.
- The effect size seems large enough to demonstrate the practical use of IMUs for predicting overstriding, making the study's findings useful for practical applications.
What do we know now that we didn't know before, if anything?
- We now know that wearable devices can be used outside of a lab setting to predict overstriding, providing an accessible tool for runners and professionals to monitor and potentially prevent injuries.
What simple and practical thing could a normal person do knowing this?
- Runners could use wearable sensors to monitor their running form in real time, adjusting their stride to prevent overstriding and reduce the risk of injury.
Back next week with quick and thoughtful takes on papers getting attention. And if you see anything you want us to look at, let us know.
