Newsletter #115: How Nature and Green Tea Might Improve the Gut Microbiome 🍵
Hello Friends!
Welcome to the latest edition of the humanOS newsletter! Below, as usual, is a roundup of the various studies and other media that we came across. 🤓
This week, we learned that exposure to nature (and animals) can help promote healthy gut microbiomes in babies; that green tea may boost a health-promoting species of intestinal bacteria; and we got a little bit more insight into the vascular benefits of passive heat therapy (also refer to this podcast to learn more about sauna use and health outcomes 👀)
Check it out, and please stay safe everyone. 👇
This Week’s Research Highlights
🧖♂️ Sauna bathing has acute vascular benefits in older adults with cardiovascular disease.
Twenty-two adults (67 ± 10 years) with stable coronary artery disease underwent two periods of 10 minutes in a Finnish sauna, separated by 10 minutes of thermoneutral rest. About an hour after, researchers found that the sauna sessions had elevated heart rate (+27 bpm), lowered systolic (-19 mmHg) and diastolic (-6 mmHg) blood pressure, and had increased brachial artery flow-mediated dilation (+1.21%). This finding lines up with previous observational studies showing that regular sauna use is associated with significantly lower risk of cardiovascular disease, as well as 61% reduced risk of suffering a stroke.
🌳 Living close to green space and with animals may help promote healthy gut microbiomes in formula-fed infants.
Researchers examined fecal samples from 355 four-month-old infants enrolled in the CHILD Cohort Study. The babies' postal codes were then cross-referenced with the City of Edmonton's urban Primary Land and Vegetation Inventory (uPLVI), which maps natural green spaces in the city. They found that infants who lived within 500 meters of a natural environment were less likely to exhibit high microbial diversity, which is actually a good thing (formula feeding tending to increase the number of species, with higher representation of harmful ones, compared to breastfeeding, which selects for persistence of beneficial bacteria). The strongest association was for formula fed infants who shared a home with a pet. A notable compositional change was enrichment of Proteobacteria, a phylum of bacteria that is ubiquitous in soil and vegetation, and which has been linked to exposure to nature.
🍵 Green tea boosts growth of beneficial bacteria in the gut.
Researchers randomly divided mice into four groups based on diet: normal diet + green tea, high-fat diet + green tea, and normal diet and high-fat diet without green tea. After 12 weeks, the researchers found that supplementation with green tea blunted the gain in fat mass and hyperlipidemia associated with the high-fat diet, and also improved glucose tolerance, as expected.
Interestingly, they also observed that green tea encouraged the growth of Akkermansia muciniphila, a mucin-degrading bacterium that appears to help maintain barrier function in the gut, reduces inflammation, and protects against metabolic disorders. The researchers further determined that epigallocatechin 3-gallate (EGCG) was the component of green tea that was responsible for driving Akkermansia growth.
Podcasts We Loved This Week
- Anthony Fauci: SARS-CoV-2 transmission, testing, immunity, pathogenesis, vaccines, and preparedness. Via This Week in Virology.
- Brian Hare: Survival of the Friendliest - Understanding Our Origins and Rediscovering Our Common Humanity. Via Nourish Balance Thrive Podcast.
- Nsikan Akpan: Can COVID-19 Spread Through the Air? Via Science Friday.
Products We Are Enjoying
MRM Superfoods Matcha
Matcha is a powder made from finely grinding green tea leaves. Because you are consuming the whole plant, as opposed to an infusion like when you use tea bags, you wind up getting more of the bioactive catechins, like EGCG (refer to the study above for why that would be a good thing). So why this brand in particular? Well, the friendly folks at Consumer Lab (a service that I highly recommend) tested a bunch of different green tea products and identified this as one of a few that was rich in beneficial compounds.
