Newsletter #77: Changing Seasons and Metabolic Health 🍂🌤️
Hello Friends!
Welcome to the latest edition of the humanOS newsletter! Here is where we share our work, plus the various studies and media that caught our attention this week. 🤓
This Week’s Research Highlights
👦 Being overweight early in life increases risk of certain cancers.
Researchers pooled health data from six European cohorts (n = 221274) with at least two height and weight measurements between 1972 and 2014. Cancer cases were identified through national cancer registries. The study revealed that subjects who were overweight before the age of 40 experienced a 15% increased risk for developing any obesity-related cancers. For some cancers, the rise in risk was particularly pronounced. For those who were overweight before the age of 40, the risk of developing cancer increased 70% for endometrial cancer, 58% for male renal-cell cancer, and 29% for male colon cancer. Unsurprisingly, being obese heightened these risks even more - the odds of developing obesity-related cancers rose 64% for men and 48% for women.
⚡ Higher energy turnover may help rein in hunger by modulating appetite-regulating hormones.
In a randomized crossover trial, 16 healthy participants were subjected to four different conditions of energy balance (ad libitum energy intake, zero energy balance, −25% caloric restriction, and +25% overfeeding) while in a metabolic chamber. These conditions were experienced at three different levels of energy expenditure, which were performed by walking on a treadmill. Compared with the high energy turnover condition, subjects with low energy turnover showed decreased GLP-1 and increased ghrelin concentrations. This was accompanied by greater hunger, and eating to the point of positive energy balance when they were allowed to eat as much as they wanted (+17.5%). Refer to our past blog and recent interview with Javier Gonzalez to learn more about the effects of exercise on appetite regulation and energy intake.
💡 Exposure to very brief flashes of light during sleep can reset the body clock and help teenagers get up earlier.
Researchers recruited high schoolers who had expressed difficulty going to bed and waking up early. In phase 1 of the clinical trial, participants were randomly assigned to receive either 3 weeks of light therapy delivered from a device in the teens’ bedrooms (3-millisecond light flashes every 20 seconds during the final 3 hours of sleep), or 3 weeks of sham light therapy. This protocol did not significantly alter sleep timing. In phase 2, participants received a slightly different light therapy (3-millisecond light flash every 20 seconds during the final 2 hours of sleep), combined with four hour-long cognitive-behavioral therapy sessions to try to motivate them to go to bed earlier. This worked - light therapy plus CBT moved sleep onset 50 minutes earlier, and increased nightly sleep time by an average of 43 minutes.
New humanOS Content
🔬 In this episode of humanOS Radio, Dan speaks with Sander Kooijman, a post-doctoral researcher at Leiden University Medical Center. He and his colleagues recently published a paper examining how light exposure and environmental temperature affect measures of glucose and lipid metabolism.
🌡️ The researchers collected data from a combined cohort of more than 10,000 healthy middle-aged subjects enrolled in two population-based European cohorts. Participants in these studies have provided body composition measurements as well as bloodwork. Sander and his team very cleverly collected data on mean outdoor temperature and hours of bright sunlight from local weather stations. From this information, they were able to calculate mean outdoor temperature and bright sunlight duration before the date of blood sampling.
☀️ Sure enough, increased bright sunlight exposure was found to be associated with lower fasting insulin, lower triglyceride levels, and reduced insulin resistance.
🎧 So, why exactly does sun exposure seem to enhance cardiometabolic health? 🤔 To find out why Sander thinks it has this effect, and more about his fascinating work, check out the podcast!
Media Featuring humanOS
- Dan Pardi: On longevity, sleep, sunlight, meal timing, and much more! Via OPEX Podcast.
Podcasts We Loved This Week
- Matthias Gruber: This is Your Brain on Curiosity. Via TEDx.
- Matt Walker: Sleep is your superpower. Via TED.
- Camilla Arndal Andersen: What happens in your brain when you taste food? Via TEDx.
Products We Are Enjoying
These bars are made primarily from organic vegetables. What I like about them is they intentionally incorporate parts of the vegetable that are often discarded - stems, skins, seeds, etc. This reduces waste and also ensures that you are consuming the most nutrient-rich parts of the plant (as discussed in this course). They are surprisingly tasty and a good pre-workout snack. Here’s a link to the trial pack if you wanna try them.