Newsletter #138: Blueberries, Avocados, & Relaxing Piano Music
Happy holidays everyone, and welcome to the Day After Christmas edition of the humanOS newsletter!
This week, we learned that eating avocados makes your gut microbes happy, eating blueberries improves cognitive function in older adults and listening to relaxing music significantly lowers blood pressure and heart rate. Good stuff!
Scroll down to learn more 👇
This Week’s Research Highlights
🥑 Eating avocados daily may improve gut health.
Researchers recruited 163 adults and randomly assigned them to two different groups. Participants consumed isocaloric meals either with or without avocado once per day for twelve weeks. At the end of the study period, the group consuming one avocado per day showed a more diverse microbiome, as well as greater amounts of microbes that ferment fiber (makes sense, since avocados are rich in fiber). The avocado group also showed higher levels of fecal short-chain fatty acids (SCFAs), as you would expect since SCFAs are metabolites generated by fiber fermentation. SCFAs are thought to be key to gut health through multiple mechanisms, including maintenance of intestinal barrier integrity, boosted gut mucus production, and attenuated inflammation. Indeed, it has been hypothesized that a major reason why the Western diet is associated with increased risk of an array of chronic diseases is because it is relatively low in microbiota-accessible carbs such as fiber. Less fiber to feed the good gut bugs in turn leads to poor production of SCFAs. Integrating healthy whole foods that are naturally rich in fiber, like avocados, into the diet is an easy way to potentially reverse this.
🍇 Daily consumption of blueberries may boost cognitive performance in older adults.
Researchers recruited 38 healthy older adults (60-75 years) and randomly divided them into blueberry or control groups. The blueberry study group consumed 24 g per day of powdered freeze-dried blueberries (equivalent to one cup per day of fresh produce). The control group consumed an apparently identical isocaloric powder. Blood samples were collected at various points throughout the study period, and a battery of cognitive tests was also administered at those points. As one would generally expect, blood samples showed that the blueberry group experienced significant increases in circulating phenolic metabolites. Changes in levels of these plasma phenolics in turn were associated with improvements in cognitive performance. This suggests that easily achievable quantities of berries in the diet may be linked to improvements in cognition, perhaps through naturally occurring polyphenolic compounds. Some prior research suggests that these blueberry compounds may increase blood flow to certain areas of the brain. They may even get into the brain itself - when rats are fed blueberries and then dissected, anthocyanins from the fruit can actually be found distributed inside the brain!
🎶 Relaxing music lowers blood pressure and heart rate.
Thirty young adults with prehypertension (systolic blood pressure = 120‐139 mmHg and diastolic blood pressure = 80‐89 mmHg) were randomly assigned into two groups. The music group received music therapy by passive listening to music for 30 minutes/day, 5 days/week for 4 weeks. (In case you’re wondering, the music used for this study was described as “The Best Relaxing Piano and Flute Music Ever.” Might be able to find it on YouTube.) They were also instructed to limit sodium intake and adopt the DASH eating plan. The control group (N = 15) practiced only the dietary modifications and were instructed to not listen to any kind of music throughout the study period. After four weeks, the music group showed a significant reduction in systolic blood pressure (-8.73 mmHG) and in heart rate (-6.42 beats per minute).
The control group showed no such improvements. This finding reminds me of another recent study that found that looking at cute animals significantly lowered both blood pressure and heart rate.
Question of the Week
🤔 Which type of Christmas tree is likely to be better for the environment: real or fake?
Podcasts We Loved This Week
- Benjamin Thompson, Noah Baker & Traci Watson: The big COVID research papers of 2020. Via Nature Podcast.
- Anthony Fauci: When life will return to normal. Via Podcast-19 (FiveThirtyEight).
Products We Are Enjoying
Wild Blueberry Juice Concentrate
It can be hard to find quality fresh berries this time of year, so something like this can be a useful alternative. And a little bit goes a long way - just one tablespoon is equivalent to one cup of wild blueberry fruit juice.
humanOS Catalog Feature of the Week
How-to Guide - Smart Daily Light
This week, we’d like to highlight our How-to Guide for Smart Daily Light. We evolved in the presence of natural daily cycles of light and darkness. But obviously, the invention of artificial lighting means that we can now fully control when and how much light we’re exposed to, which has altered this relationship. Today, most of us spend the majority of the day indoors, under comparatively dim artificial lights. Then, after sundown, we are exposed to more bright light, and importantly more blue light due to our digital devices. Consequently, we are getting less bright light during the day and less darkness at night.
This is important because light sends crucial signals to the body, and the intensity and timing of this light matters for your health as well as your performance. But fortunately, there is a lot you can do about it. In this guide, we discuss how you can achieve a pattern of natural light and darkness in the modern world by adjusting behavior, modifying your indoor spaces, configuring your devices, and more.