L-Theanine: What’s The Tea?

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L-Theanine: What’s The Tea?

We’ve touched previously on l-theanine, when this newsletter was new, and we had only a few hundred subscribers and the carefully organized format wasn’t yet what it is today.

So now it’s time to give this potent dietary compound / nutritional supplement the “Monday Research Review” treatment…

What is it?

L-theanine is an amino acid found in tea. The human body can’t produce it, and/but it’s not essential for humans. It does have a lot of benefits, though. See for example:

L-Theanine as a Functional Food Additive: Its Role in Disease Prevention and Health Promotion

How does it work?

L-theanine works by moderating and modulating the brain’s neurotransmitters.

This sounds fancy, but basically it means: it doesn’t actually add anything in the manner of a drug, but it changes how we use what we have naturally.

What does it do? Read on…

It increases mental focus

It has been believed that l-theanine requires the presence of caffeine to achieve this (i.e., it’s a combination-only effect). For example:

The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness

But as it turns out, when a group of researchers actually checked… This isn’t true, as Foxe et al. write:

❝We asked whether either compound alone, or both in combination, would affect performance of the task in terms of reduced error rates over time, and whether changes in alpha-band activity would show a relationship to such changes in performance. When treated with placebo, participants showed a rise in error rates, a pattern that is commonly observed with increasing time-on-task, whereas after caffeine and theanine ingestion, error rates were significantly reduced. The combined treatment did not confer any additional benefits over either compound alone, suggesting that the individual compounds may confer maximal benefits at the dosages employed❞

See: Assessing the effects of caffeine and theanine on the maintenance of vigilance during a sustained attention task

It promotes a calmly wakeful feeling of serenity

Those are not words typically found in biopharmaceutical literature, but they’re useful here to convey:

  • L-theanine promotes relaxation without causing drowsiness
  • L-theanine promotes mental alertness without being a stimulant

Here is where l-theanine really stands out from caffeine. If both substances promote mental focus, but one of them does it by making us “wired” and the other does it while simultaneously promoting calm, it makes the choice between them clearer!

Read more: L-theanine, a natural constituent in tea, and its effect on mental state

It relieves stress and anxiety

Building on from the above, but there’s more: l-theanine relieves stress and anxiety in people experiencing stressful situations, without any known harmful side effects… This is something that sets it apart from a lot of anxiolytic (antianxiety) drugs!

Here’s what a big systematic review of clinical trials had to say:

Theanine consumption, stress and anxiety in human clinical trials: A systematic review

L-theanine has other benefits too

We’ve talked about some of the most popular benefits of l-theanine, and we can’t make this newsletter too long, but research also suggests that it…

If you’re interested in this topic, we recommend also reading our previous article on l-theanine—pardon that we hadn’t really nailed down our style yet—but there’s a bunch of useful information about how l-theanine makes caffeine “better” in terms of benefits. We also talk dosage, and reference some other studies we didn’t have room to include today!

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  • The Yoga of Breath – by Richard Rosen

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    You probably know to breathe through your nose, and to breathe with your diaphragm. But did you know you’re usually only breathing through one nostril at a time, and alternate between nostrils every few hours? And did you know how to breathe through both nostrils equally instead, and the benefits that can bring?

    The above is one example of many, of things that make this book stand out from the crowd when it comes to breathing exercises. Author Richard Rosen has a deep expertise in this topic, and explains everything clearly and comprehensively, without leaving room for ambiguity.

    While most of the book focuses on the mechanics and physical techniques of breathing, he does also cover some more mindstate-related things too—without which, it wouldn’t be yoga.

    If the book has a downside, it’s that its comprehensive nature could be off-putting to readers new to breathing work in general. However, since he does explain everything from the ground up, that’s no reason to be put off this book, iff you’re serious about learning.

    Bottom line: if you’d like a deeper understanding of breathwork than “breathe slowly through your nose, using your diaphragm”, this book will teach you depths of breathing you probably didn’t know were possible.

    Click here to check out The Yoga of Breath, and catch yours!

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  • Mythbusting Moldy Food

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    Most Food Should Not Be Fuzzy

    In yesterday’s newsletter, we asked you for your policy when it comes to mold on food (aside from intentional mold, e.g. blue cheese etc), and the responses were interesting:

    • About 49% said “throw the whole thing away no matter what it is; it is dangerous
    • About 24% said “cut the mold off and eat the rest of whatever it is
    • The remainder were divided equally between “eat it all; keep the immune system on its toes” and “cut the mold off bread, but moldy animal products are dangerous

    So what does the science say?

    Some molds are safe to eat: True or False?

    True! We don’t think this is contentious so we’ll not spend much time on it, but just for the sake of being methodical: foods that are supposed to have mold on, including many kinds of cheese and even some kinds of cured meat (salami is an example; that powdery coating is mold).

    We could give a big list of safe and unsafe molds, but that would be a list of names and let’s face it, they don’t introduce themselves by name.

    However! The litmus test of “is it safe to eat” is:

    Did you acquire it with this mold already in place and exactly as expected and advertised?

    • If so, it is safe to eat (unless you have an allergy or such)
    • If not, it is almost certainly not safe to eat

    (more on why, later)

    The “sniff test” is a good way to tell if moldy food is bad: True or False?

    False. Very false. Because of how the sense of smell works.

    You may feel like smell is a way of knowing about something at a distance, but the only way you can smell something is if particles of it are physically connecting with your olfactory receptors inside you. Yes, that has unfortunate implications about bathroom smells, but for now, let’s keep our attention in the kitchen.

    If you sniff a moldy item of food, you will now have its mold spores inside your respiratory system. You absolutely do not want them there.

    If we cut off the mold, the rest is safe to eat: True or False?

    True or False, depending on what it is:

    • Hard vegetables (e.g carrots, cabbage), and hard cheeses (e.g. Gruyère, Gouda) – cut off with an inch margin, and it should be safe
    • Soft vegetables (e.g. tomatoes, and any vegetables that were hard but are now soft after cooking) – discard entirely; it is unsafe
    • Anything elsediscard entirely; it is unsafe

    The reason for this is because in the case of the hard products mentioned, the mycelium roots of the mold cannot penetrate far.

    In the case of the soft products mentioned, the surface mold is “the tip of the iceberg”, and the mycelium roots, which you will not usually be able to see, will penetrate the rest of it.

    Anything else” seems like quite a sweeping statement, but fruits, soft cheeses, yogurt, liquids, jams and jellies, cooked grains and pasta, meats, and yes, bread, are all things where the roots can penetrate deeply and easily. Regardless of you only being able to see a small amount, the whole thing is probably moldy.

    The USDA has a handy downloadable factsheet:

    Molds On Food: Are They Dangerous?

    Eating a little mold is good for the immune system: True or False?

    False, generally. There are of course countless types of mold, but not only are many of them pathogenic (mycotoxins), but also, a food that has mold will usually also have pathogenic bacteria along with the mold.

    See for example: Occurrence, Toxicity, and Analysis of Major Mycotoxins in Food

    Food poisoning will never make you healthier.

    But penicillin is safe to eat: True or False?

    False, and also penicillin is not the mold on your bread (or other foods).

    Penicillin, an antibiotic* molecule, is produced by some species of Penicillium sp., a mold. There are hundreds of known species of Penicillium sp., and most of them are toxic, usually in multiple ways. Take for example:

    Penicillium roqueforti PR toxin gene cluster characterization

    *it is also not healthy to consume antibiotics unless it is seriously necessary. Antibiotics will wipe out most of your gut’s “good bacteria”, leaving you vulnerable. People have died from C. diff infections for this reason. So obviously, if you really need to take antibiotics, take them as directed, but if not, don’t.

    See also: Four Ways Antibiotics Can Kill You

    One last thing…

    It may be that someone reading this is thinking “I’ve eaten plenty of mold, and I’m fine”. Or perhaps someone you tell about this will say that.

    But there are two reasons this logic is flawed:

    • Survivorship bias (like people who smoke and live to 102; we just didn’t hear from the 99.9% of people who smoke and die early)
    • Being unaware of illness is not being absent of illness. Anyone who’s had an alarming diagnosis of something that started a while ago will know this, of course. It’s also possible to be “low-level ill” often and get used to it as a baseline for health. It doesn’t mean it’s not harmful for you.

    Stay safe!

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  • Alzheimer’s Causative Factors To Avoid

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    The Best Brains Bar Nun?

    This is Dr. David Snowdon. He’s an epidemiologist, and one of the world’s foremost experts on Alzheimer’s disease. He was also, most famously, the lead researcher of what has become known as “The Nun Study”.

    We recently reviewed his book about this study:

    Aging with Grace: What the Nun Study Teaches Us About Leading Longer, Healthier, and More Meaningful Lives – by Dr. David Snowdon

    …which we definitely encourage you to check out, but we’ll do our best to summarize its key points today!

    Reassurance up-front: no, you don’t have to become a nun

    The Nun Study

    In 1991, a large number (678) of nuns were recruited for what was to be (and until now, remains) the largest study of its kind into the impact of a wide variety of factors on aging, and in particular, Alzheimer’s disease.

    Why it was so important: because the nuns were all from the same Order, had the same occupation (it’s a teaching Order), with very similar lifestyles, schedules, socioeconomic status, general background, access to healthcare, similar diets, same relationship status (celibate), same sex (female), and many other factors also similar, this meant that most of the confounding variables that confound other studies were already controlled-for here.

    Enrollment in the study also required consenting to donating one’s brain for study post-mortem—and of those who have since died, indeed 98% of them have been donated (the other 2%, we presume, may have run into technical administrative issues with the donation process, due to the circumstances of death and/or delays in processing the donation).

    How the study was undertaken

    We don’t have enough space to describe the entire methodology here, but the gist of it is:

    • Genetic testing for relevant genetic factors
    • Data gathered about lives so far, including not just medical records but also autobiographies that the nuns wrote when they took their vows (at ages 19–21)
    • Extensive ongoing personal interviews about habits, life choices, and attitudes
    • Yearly evaluations including memory tests and physical function tests
    • Brain donation upon death

    What they found

    Technically, The Nun Study is still ongoing. Of the original 678 nuns (aged 75–106), three are still alive (based on the latest report, at least).

    However, lots of results have already been gained, including…

    Genes

    A year into the study, in 1992, the “apolipoprotein E” (APOE) gene was established as a likely causative factor in Alzheimer’s disease. This is probably not new to our readers in 2024, but there are interesting things being learned even now, for example:

    The Alzheimer’s Gene That Varies By Race & Sex

    …but watch out! Because also:

    Alzheimer’s Sex Differences May Not Be What They Appear

    Words

    Based on the autobiographies written by the nuns in their youth upon taking their vows, there were two factors that were later correlated with not getting dementia:

    • Longer sentences
    • Positive outlook
    • “Idea density”

    That latter item means the relative linguistic density of ideas and complexity thereof, and the fluency and vivacity with which they were expressed (this was not a wishy-washy assessment; there was a hard-science analysis to determine numbers).

    Want to spruce up yours? You might like to check out:

    Reading, Better: Reading As A Cognitive Exercise

    …for specific, evidence-based ways to tweak your reading to fight cognitive decline.

    Food

    While the dietary habits of the nuns were fairly homogenous, those who favored eating more and cooked greens, beans, and tomatoes, lived longer and with healthier brains.

    See also: Brain Food? The Eyes Have It!

    Other aspects of brain health & mental health

    The study also found that nuns who avoided stroke and depression, were also less likely to get dementia.

    For tending to these, check out:

    Community & Faith

    Obviously, in this matter the nuns were quite a homogenous group, scoring heavily in community and faith. What’s relevant here is the difference between the nuns, and other epidemiological studies in other groups (invariably not scoring so highly).

    Community & faith are considered, separately and together, to be protective factors against dementia.

    Faith may be something that “you have it or you don’t” (we’re a health science newsletter, not a theological publication, but for the interested, philosopher John Stuart Mill’s 1859 essay “On Liberty“ makes a good argument for it not being something one can choose, prompting him to argue for religious tolerance, on the grounds that religious coercion is a futile effort precisely because a person cannot choose to dis/believe something)

    …but community can definitely be chosen, nurtured, and grown. We’ve written about this a bit before:

    You might also like to check out this great book on the topic:

    Purpose: Design A Community And Change Your Life – by Gina Bianchini

    Want more?

    We gave a ground-up primer on avoiding Alzheimer’s and other dementias; check it out:

    How To Reduce Your Alzheimer’s Risk

    Take care!

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  • Welcoming the Unwelcome – by Pema Chödrön

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    There’s a lot in life that we don’t get to choose. Some things we have zero control over, like the weather. Others, we can only influence, like our health. Still yet others might give us an illusion of control, only to snatch it away, like a financial reversal or a bereavement.

    How, then, to suffer those “slings and arrows of outrageous fortune” and come through the other side with an even mind and a whole heart?

    Author Pema Chödrön has a guidebook for us.

    Quick note: this book does not require the reader to have any particular religious faith to enjoy its benefits, but the author is a nun. As such, the way she describes things is generally within the frame of her religion. So that’s a thing to be aware of in case it might bother you. That said…

    The largest part of her approach is one that psychology might describe as rational emotive behavioral therapy.

    As such, we are encouraged to indeed “meet with triumph and disaster, and treat those two imposters just the same”, and more importantly, she lays out the tools for us to do so.

    Does this mean not caring? No! Quite the opposite. It is expected, and even encouraged, that we might care very much. But: this book looks at how to care and remain compassionate, to others and to ourselves.

    For Chödrön, welcoming the unwelcome is about de-toothing hardship by accepting it as a part of the complex tapestry of life, rather than something to be endured.

    Bottom line: this book can greatly increase the reader’s ability to “go placidly amid the noise and haste” and bring peace to an often hectic world—starting with our own.

    Click here to check out Welcoming the Unwelcome, and learn what’s practically a superpower in this sometimes crazy world.

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  • What’s the difference between physical and chemical sunscreens? And which one should you choose?

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    Sun exposure can accelerate ageing, cause skin burns, erythema (a skin reaction), skin cancer, melasmas (or sun spots) and other forms of hyperpigmentation – all triggered by solar ultraviolet radiation.

    Approximately 80% of skin cancer cases in people engaged in outdoor activities are preventable by decreasing sun exposure. This can be done in lots of ways including wearing protective clothing or sunscreens.

    But not all sunscreens work in the same way. You might have heard of “physical” and “chemical” sunscreens. What’s the difference and which one is right for you?

    How sunscreens are classified

    Sunscreens are grouped by their use of active inorganic and organic ultraviolet (UV) filters. Chemical sunscreens use organic filters such as cinnamates (chemically related to cinnamon oil) and benzophenones. Physical sunscreens (sometimes called mineral sunscreens) use inorganic filters such as titanium and zinc oxide.

    These filters prevent the effects of UV radiation on the skin.

    Organic UV filters are known as chemical filters because the molecules in them change to stop UV radiation reaching the skin. Inorganic UV filters are known as physical filters, because they work through physical means, such as blocking, scattering and reflection of UV radiation to prevent skin damage.

    Nano versus micro

    The effectiveness of the filters in physical sunscreen depends on factors including the size of the particle, how it’s mixed into the cream or lotion, the amount used and the refraction index (the speed light travels through a substance) of each filter.

    When the particle size in physical sunscreens is large, it causes the light to be scattered and reflected more. That means physical sunscreens can be more obvious on the skin, which can reduce their cosmetic appeal.

    Nanoparticulate forms of physical sunscreens (with tiny particles smaller than 100 nanometers) can improve the cosmetic appearance of creams on the skin and UV protection, because the particles in this size range absorb more radiation than they reflect. These are sometimes labelled as “invisible” zinc or mineral formulations and are considered safe.

    So how do chemical sunscreens work?

    Chemical UV filters work by absorbing high-energy UV rays. This leads to the filter molecules interacting with sunlight and changing chemically.

    When molecules return to their ground (or lower energy) state, they release energy as heat, distributed all over the skin. This may lead to uncomfortable reactions for people with skin sensitivity.

    Generally, UV filters are meant to stay on the epidermis (the first skin layer) surface to protect it from UV radiation. When they enter into the dermis (the connective tissue layer) and bloodstream, this can lead to skin sensitivity and increase the risk of toxicity. The safety profile of chemical UV filters may depend on whether their small molecular size allows them to penetrate the skin.

    Chemical sunscreens, compared to physical ones, cause more adverse reactions in the skin because of chemical changes in their molecules. In addition, some chemical filters, such as dibenzoylmethane tend to break down after UV exposure. These degraded products can no longer protect the skin against UV and, if they penetrate the skin, can cause cell damage.

    Due to their stability – that is, how well they retain product integrity and effectiveness when exposed to sunlight – physical sunscreens may be more suitable for children and people with skin allergies.

    Although sunscreen filter ingredients can rarely cause true allergic dermatitis, patients with photodermatoses (where the skin reacts to light) and eczema have higher risk and should take care and seek advice.

    What to look for

    The best way to check if you’ll have a reaction to a physical or chemical sunscreen is to patch test it on a small area of skin.

    And the best sunscreen to choose is one that provides broad-spectrum protection, is water and sweat-resistant, has a high sun protection factor (SPF), is easy to apply and has a low allergy risk.

    Health authorities recommend sunscreen to prevent sun damage and cancer. Chemical sunscreens have the potential to penetrate the skin and may cause irritation for some people. Physical sunscreens are considered safe and effective and nanoparticulate formulations can increase their appeal and ease of use.The Conversation

    Yousuf Mohammed, Dermatology researcher, The University of Queensland and Khanh Phan, Postdoctoral research associate, Frazer Institute, The University of Queensland

    This article is republished from The Conversation under a Creative Commons license. Read the original article.

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  • The End of Old Age – by Dr. Marc Agronin

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    First, what this book is not: a book about ending aging. For that, you would want to check out “Ending Aging”, by Dr. Aubrey de Grey.

    What this book actually is: a book about the purpose of aging. As in: “aging: to what end?”, and then the book answers that question.

    Rather than viewing aging as solely a source of decline, this book (while not shying away from that) resolutely examines the benefits of old age—from clinically defining wisdom, to exploring the many neurological trade-offs (e.g., “we lose this thing but we get this other thing in the process”), and the assorted ways in which changes in our brain change our role in society, without relegating us to uselessness—far from it!

    The style of the book is deep and meaningful prose throughout. Notwithstanding the author’s academic credentials and professional background in geriatric psychiatry, there’s no hard science here, just comprehensible explanations of psychiatry built into discussions that are often quite philosophical in nature (indeed, the author additionally has a degree in psychology and philosophy, and it shows).

    Bottom line: if you’d like your own aging to be something you understand better and can actively work with rather than just having it happen to you, then this is an excellent book for you.

    Click here to check out The End Of Old Age, and live it!

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