Newsletter #211 - Impressive Health Effects of Herbal Tea 🌺
Welcome to the Memorial Day weekend edition of the humanOS newsletter (for those of us in the US). Today, I thought I’d take a look at some of the most promising research examining the effects of herbal tea.
I think we’ve reviewed the benefits of “true” tea several times here before (by that, I am referring to tea made from Camellia sinensis, like green tea and black tea), which is great.
But I think infusions from other plants are sorely underappreciated. They are often very high in bioactive compounds like polyphenols, and most of them are caffeine-free so you can drink them all day and all night. They’re also an easy source of phytochemicals for people who eat lower carb (and thus lower plant) diets, since they’re generally very low in sugars. Finally, they tend to be pretty tasty, so drinking them can help ensure that you’re well hydrated, which is always a good thing, right?
I chose to highlight hibiscus, rooibos, and chamomile, but there are dozens of other varieties out there that are also super healthy. I’d recommend buying some sampler packs and trying a bunch of different types to see what agrees with you.
This Week's Research Highlights
🫖 Hibiscus tea lowers blood pressure.
Researchers recruited 65 volunteers with elevated blood pressure, and randomly assigned them to two groups. One group was instructed to drink three cups of hibiscus tea daily, and the others drank an identical volume of that placebo beverage made from an artificial hibiscus flavor concentrate. After six weeks of the regimen, the participants who had consumed the hibiscus tea experienced a 7.2 mm Hg decrease in their systolic blood pressure. Individuals who entered the study with higher blood pressure showed a more dramatic response: they showed a 13.2 point drop in systolic blood pressure, a 6.4 point drop in diastolic blood pressure, and a decrease in mean arterial pressure of 8.7 points. This is supported by a previous trial which found that supplementation with hibiscus resulted in blood pressure reductions similar to that of an ACE inhibitor.
🩸 Rooibos tea improves blood lipids and redox status.
Researchers in South Africa recruited forty volunteers at high cardiovascular risk and had them drink six cups of traditional (fermented) rooibos tea daily for six weeks. Then, after a two week washout, the participants were followed for a six week control period. Rooibos consumption resulted in a significant decrease in plasma markers of lipid peroxidation. They also showed significantly higher levels of reduced glutathione (GSH), and the ratio of reduced glutathione to oxidized glutathione (GSSG) was also higher compared to control (76 ± 17 vs. 41 ± 14). The reason why that matters is the ratio of reduced glutathione and oxidized glutathione is often used as a measure of oxidative stress and the health of cells, and tends to decline with age. In other words, you generally want to see more GSH and less GSSG. Finally, their lipid profile also substantially improved: Compared to control, drinking rooibos tea resulted in lower LDL cholesterol (151 ± 27 mg/dL vs. 178 ± 50 mg/dL), lower triglycerides (106 ± 62 mg/dL vs 151 ± 71 mg/dL), and higher HDL (46 ± 8 mg/dL vs. 35 ± 4 mg/dL ).
☕️ Drinking chamomile tea is associated with lower all-cause mortality.
Researchers at the University of Texas Medical Branch at Galveston analyzed data from 1677 Mexican-Americans aged 65 and older, who were followed for seven years. After adjusting for health behaviors, chronic conditions, and sociodemographic variables, the researchers found that women who drank chamomile tea regularly had a 28% lower risk of all-cause mortality. Underlying mechanisms are unclear. However, chamomile is one of the richest natural sources of apigenin, a flavanone which has shown some promise in preclinical models of cancer and other diseases, so perhaps that compound is playing a role.
Random Trivia & Weird News
🫖 Men in the nineteenth century used special mustache cups to keep their whiskers dry while drinking tea.
The mid- to late-1800s was a sort of golden age for mustaches (a google image search will reveal some particularly impressive examples). But these styles often demanded the use of waxes and other products to maintain their distinctive shapes, which obviously becomes a bit of a problem when your mouth is brought in close proximity to steaming hot liquids.
That led to the development of special mugs with little butterfly-shaped guards, which apparently were massively popular back in the day. They don’t seem to be as much of a thing now, despite the contemporary resurgence of statement facial hair, although I did find one example on Amazon.
Podcasts We Loved This Week
- Jed Fahey: The power of phytochemicals. Via The Proof Podcast.
- Fiona McNeill: Could lead makeup really kill you? A scientist recreated centuries-old skin whitening recipes to find out. Via The Conversation.
Products We Are Enjoying
Celestial Seasonings Lemon Zinger tea
I've always been a fan of the various “Zinger” teas, but the reason why I am mentioning it today is because the first ingredient in this tea is not lemon peel, or any kind of citrus for that matter - it’s actually hibiscus (hence the slightly sour taste).
Hibiscus has been found to lower blood pressure, perhaps by increasing nitric oxide production. And the researchers for the study described above actually acquired the hibiscus flowers that they used from Celestial Seasonings, and got those impressive results, so it is ostensibly a pretty legit source. Lemon Zinger is also very tasty as iced tea (arguably better than hot), so it’s very amenable to oppressive summertime heat.
humanOS Catalog Feature of the Week
How-to Guide - Overcoming Jetlag
As we progress into summertime and appear to be emerging from the worst of the pandemic (knock on wood), it seems like more and more people are getting out and traveling again. Consequently, a lot of us are probably going to be battling jet lag, perhaps for the first time in a while. Jet lag simply refers to a misalignment between the timing of your body clock and the timing of your environment. And until your body becomes re-synchronized to your new time zone, your physical and mental performance is apt to suffer. Is it possible to accelerate this adaptation?
Yes! That’s why we developed this guide, based on state-of-the-art research on circadian alignment. In this doc, we tell you how you can adjust to a new time zone faster, and even give you instructions on how to put together a simple DIY device to shift your body clock really fast (we call it Time Warp). You can also refer to our past interview with Stanford professor Jamie Zeitzer, an expert on jetlag who has done a ton of research on novel ways to adjust to transmeridian travel.
Thanks for reading, enjoy the weekend, and we'll see y'all next week!