The cancellation of Andrew Huberman, science-lifestyle podcaster

 

To me this is an interesting story.  A well-regarded, well-credentialed, science-oriented life advice podcaster--Andrew Huberman--rises to new heights of fame and following, and is later "cancelled" for personal reasons, basically for having 5 or more exclusive relationship girlfriends at the same time.  

Should that get him cancelled?  What does it really mean in relation to that life advice?  To me those aren't even the most interesting angles.  The better questions that arise relate to why so many people accepted his ideas so completely, and why opinions are divided between seeing his personal life choices as not relevant and this calling into question his general credibility.

It all originated from this New York magazine story, Andrew Huberman’s Mechanisms of Control :The private and public seductions of the world’s biggest pop neuroscientist.  I just noticed that they put "Joe Rogan" in the web page name, even though he played essentially no part in any of this, beyond helping Huberman rise to fame.  That's SEO I guess.

Let's work backwards, and start with what he did, and then who he is, on to how to take this.  He was in a relationship that was framed as monogamous with one woman, over a period of years, extending that as far as attempting to have children at one point (allegedly; it's hard to know how much of any one-source account is accurate).  Then it turned out that he was in serious relationships with at least 4 other women at the same time, and maybe more.  The coordination is admirable, on one level.

So what?  The problem was that he communicated the relationships were exclusive to each, per the story, not only adjusting his partners' expectations but influencing their decision to have unprotected sex, which is lower risk in an exclusive relationship.  Per the story spreading STDs did come up, which have been rebranded as STIs in recent times, broadened to include other conditions.  It's all not such unusual behavior, but it is immoral.

I've seen Huberman on some podcasts but I wasn't really a follower.  The ideas seemed fine, including some that I already subscribed to.  He recommended that people shouldn't even consume moderate amounts of alcohol, not for moral reasons, but because it causes more health impact than is generally accepted.  I essentially quit drinking alcohol some years ago, maybe 5 or 6, and drank very little for a decade before that, and it does seem like life might balance a little better without that input.  He recommended getting sun early in the day, and moderating or adjusting the form of caffeine intake, and any number of other things (including ice baths, maybe?).  Most of it is probably pretty good, well-grounded advice.

It's odd that all this isn't really directly derived from his scientific researcher background, or so it seems.  Per that article he researched optical conditions and regeneration capabilities in mice, pretty far from the scope of all this life advice.  He could sort through scientific materials in a different way than others, based on the general background, and what he pursued of his own interests might be directly relevant, based on sound research, and worthy of sharing.

Let's clear up a bit of extra context and tangents and then move on to the main themes, how this cancellation worked out, and what seems interesting about it to me.  To frame where I stand on the general research based advice theme, I've been following another "science-guy" Youtube channel that perhaps overlaps in scope, Physionic, described as follows:

Detailed multi-study analyses, clear explanations of mechanisms underlying the results, and a sprinkling of cheeky humor. Learn your body, from the macro to the micro - welcome to Physionic.

So I can relate to the instinctive desire to learn from someone who is drawing on and summarizing research materials that it would be hard to interpret, related to diet, exercise, supplement use, new atypical practice topics like ice baths, and so on.  I get how credentials, charisma, and well-grounded information could be more compelling in combination.  The Leo and Longevity Youtube channel had been a similar resource, focused more on longevity and experimental drug use, or steroids and such, but Leo died under mysterious circumstances last year, leading to me searching out a replacement, Physionic.

I've recently ran across a Reddit Huberman sub (group), which is the main prompt to write this post.  They're rejecting him there now; it's one sided, and even a bit ugly.  The comments on that original article, describing his relationship issues, are divided; half say that his personal relationships aren't relevant to his role as a "pop neuroscientist," with the other half calling into question his personal credibility.  The reason that resource made the subject more interesting is that I find the reactions interesting.

One odd input condition stands out in that article, tied to the latter theme:  Huberman is endorsed by Athletic Greens.  Per my understanding that product theme works off the older spirulina miracle food status by mixing lots of other natural inputs or supplements with that.  Then that can be regarded as controversial, because they combine 75 ingredients into a supplement marketed as a way to replace vegetable input in the diet.  This quote sums that up, from their website:

that's Huberman saying that

Could you get a basis of important vitamins, minerals, and probiotics from a scoop or two of that per day?  Maybe, but it seems doubtful.  If it was designed to be more like Soylent, a balanced input supplement designed to replace a meal then that kind of large-scope claim seems more likely, not as a green foods variation of a protein shake.

Why his relationship status doesn't matter, the argument

Seems obvious enough, but let's go there.  It's Huberman's business who he dates, and if he misrepresents his relationship status with women that's a bit sketchy but it's still up to him.  The life advice / pop neuroscientist theme is relatively completely separate.

This response and perspective is a critique of cancel culture, of the pattern of blaming individuals and and striking them down from public acceptance for personal shortcomings, even when these aren't even close to illegal activity, or even vaguely related to why they are popular, or tied to what they communicate.  This resonates with me; I think if Huberman is giving useful, science-based life advice then how he manages dating and relationships isn't relevant to that theme.

Why connecting relationship issues and giving practical life advice makes sense

There is something to this theme of critiquing general reliability and authenticity.  Within the scope of longevity study, for example, research into extending human life-span, cases of researchers recommending supplements that they have a commercial interest in comes up.  It seems possible that the science based, practical guidance could be adjusted when it relates to the person offering it making money off it.

This isn't that case though.  It moves the concern all the way back to far more general reliability; is this a trustworthy individual?  I don't have a great read on Huberman, for not having seen much of his content, but my initial impression was positive.  Just not positive enough to seek out more content, I guess, but then I'm pretty inconsistent about what I watch on Youtube.  It ends up being filtered more for varying and random subject interest than practical impact, so that I might be watching content on cave diving one week and about streamed content reviews for shows that I don't watch the next.

To me the Athletic Greens / AG1 sponsorship really is a bit more troubling.  That's fine for content producers like Joe Rogan; if any viewers are making life choices or supplement purchases based on his input that's up to them, and they have to already know that it's not grounded by the latest scientific research.  Huberman should be more careful.  Is it that Athletic Greens might really be a fantastic product?  Instead of being unconvinced I'm more actively skeptical, and doubt it, but in fairness I don't know.

Just because Huberman continually lied to some of the people he was closest to in personal life that doesn't mean that he would be dishonest about findings he communicates in his podcast.  If the right conditions came up he probably would, but it's not clear that they ever do, beyond that one sponsor endorsement issue.

Extremist reactions from Huberman followers

This might be the most interesting part.  People in that Reddit sub are already talking about cancelling Athletic Greens subscriptions, and potentially disregarding the other life advice that they had accepted.  I'm not really going to address that here, that some people are taking this so seriously, as if it changes everything.  Maybe it should, but not everyone would follow that logic.

It's interesting to me that people were seeking out this kind of reference and personal authority to follow to begin with.  As a personable, interesting, and potentially valuable information source why not; Huberman's podcast was probably novel and helpful.  Positioning him as a thought leader or life coach I don't get.

And this is also why people feel so personally betrayed, related to him not being the person they thought he was.  But then they had no idea how he managed his personal life, so all that was projection from an online persona image anyway.  

If he was just sharing some ideas, drawing on research and his own developed perspective, then none of that matters.  If he had been taken up and placed in a role model / life coach role it all shifts.

Then source-image branding factors in.  He was built up as the next great resource, as I took the framing.  That guy that creates Physionic content isn't like that; he frames himself as an advanced grad student researcher sorting out some modern themes, like whether turmeric works or not, or whether doing more or less reps when weightlifting is better (just more on the drug / supplement theme side).  

Leo of Leo and Longevity was always framed as kind of an unconventional, strange guy; he started his Youtube career as a penis extension specialist, then moved on to longevity and biohacking themes, talking a lot about steroids.  He openly said that others shouldn't experiment as much and as freely as he did, with lots of things.  Part of his personal exploration involved taking significant risks, not following well-established and grounded practices.  Huberman framed it all as solid life-practice advice, both explicitly and implicitly.  

When it came up that Leo had abusive tendencies in his marriage relationship--as I remember those circumstances--his popularity dipped, and he became inactive for a time, but there wasn't an established idealistic image that he wasn't living up to.  He was always out there.  Huberman was supposed to be some sort of ultra-modern, research oriented, renaissance man.

Maybe he still is that; he was never supposed to be perfect.  Maybe this will be the rare case where all of this blows over.  More likely the drop in popularity that was going to cycle through eventually will be triggered now, and he will retain influence and popularity with some proportion of his earlier audience.  A podcaster like Joe Rogan might have him on again just to talk through cancel culture experience, to highlight how he and his platform are immune to the whims of people who want to initiate that pattern.  It will be interesting to see, but I won't be following it closely, since I never really was a fan anyway.  I'm more a student of these kinds of patterns; to me they are interesting.

One last take

This was an interesting summary, a post in that Huberman Reddit sub titled I'm disgusted by how much I relish this:

On the whole, I enjoyed Huberman's podcast. Setting aside the exhausting tedium and BS ads for supplements and salt, I took away a lot of useful information. In the wake of the NY Mag article, though, I'm getting a kind of sick enjoyment from watching the dumpster fire.

Maybe it's alleviating an insecurity in me, seeing someone I subconsciously compared myself to get exposed as being so egregiously flawed. Maybe it's satisfying to watch deplorable behavior being met with justice. Maybe it's cathartic to imagine a vaguely smug demeanor getting wiped off someone's face.

Whatever the case, in the last couple days, I've been on this subreddit more than in all the time leading up, and I get the sense that it's not very healthy or productive for me to keep indulging in someone else's demise, at least not at this rate. Just thought I'd put that out there in case it resonates with anyone.

It might not be that people are so upset over their hero being torn down, or that people who were always skeptical are happy to be validated.  It may just be that people love to watch things burn.

Greengold Georgian black teas comparison, Taiguli and Kolkhida

 

I'm back to reviewing, trying out two Greengold Georgian black teas, Taiguli and Kolkhida versions.  Those names don't mean anything to me, so I'll cite their website descriptions following:

TAIGULI, in English meaning “Bouquet”, is made from freshly harvested finest tea leaves. Full of tips and plucked by the hands of the local villagers. Made according to the traditional Georgian Black Tea technology, with some corrections of the modern one, that gives an unique taste.

An ideal fine tea to drink until mid-afternoon. The light amber color indicates that it is a black tea. It is a clean tea since it does not present any glaze or deposits. Bright and alive tea. The aromatic intensity is moderate.

The liquor has a predominant malt aroma. The wood is sharp and you could almost tell it is unique. The taste of the tea is sweet at first but is slightly bitter and light-bodied when swallowed.

KOLKHIDA  TEA is made on Black seaside historical region “Kolkheti Lowland”, where high mountain fresh air meets the sea breeze. This special place has it’s unique climate which has an effect on the leaves. Unique KOLKHIDA taste, which you can find only in Georgia, comes from the Kolkhida tea leaves, which is massively used in this tea.

A fine tea, clean and bright, apparently dense, that can accompany you throughout the day. The liqueur displays malty, spicy and cooked lemon aromas. Sweet tea with a smooth body. The malt flavour remains for a long time. You can also appreciate a camphor flavour that gives a burning sensation.

I might also mention that the last set of teas I tried from them, also sent by Nika of Greengold for review, was fantastic, much better than I could have expected they would be.  I suppose that set a high level of expectations for these, and although they were pretty good it was a lot to live up to.

We had talked to Nika in a meetup back in 2021, which includes more of his story, about renewing production at an older tea plantation in Georgia.  That's covered in very limited detail here, in a post with more about two of the earlier black teas.

Nika, and tea plants

I've just moved back to Honolulu, here for 3 months to rejoin the kids, who are finishing up their second school year over that time, who I've been separated from for almost all of the past 7 months.  It's great, being in Hawaii.  I should write a post about what it's like here, since adding a couple of pictures and a couple of sentences wouldn't do it justice.  

Probably being at the tail end of jet lag and busy with kids' spring break activities didn't help with this review.  It was rushed, as they tend to be, but I had less initial focus to work with.  Brewed tea color is all over the place, surely related to shifting infusion timing.  Part of that relates to zeroing in on an optimum, and checking results at different infusion intensities, and it's also partly about that lack of focus.  It's not quiet where I live now.

Review:

Taiguli:  a little light; I used the standard approach of getting a first impression from a light round before a true review test.  This is interesting; moderate oxidation level input maybe?  Flavors are warm and pleasant, along the line of soft and warm malt.  It has some oolong character for lacking much astringency edge, and being soft and full.

Kolkhida:  this tastes like a familiar flavor set from teas sold as Golden Monkey in China.  Those teas always have a Chinese name too, and a typical origin area background, but that's the kind of thing I explored more in my first years trying and writing about teas, that particular type range.  Later I stayed more focused on Dian Hong, with Fujian, Chaozhou area, and Taiwanese blacks mixed in.  A different but related malt range stands out.  This extends more into rye bread scope as well.  A stronger infusion will help with adding more flavor and character breakdown.

To clarify I don't think this is a complete match for that style; I'm adding these comparisons as a reference point.  The teas definitely weren't made to copy any Chinese versions; they're presented as local products that represent modern, updated interpretations of traditional local tea styles.

Taiguli, #2:  I might have went a little strong, compensating for the slow start, brewing these for about 20 seconds.  This definitely has some edge now.  The flavor set is interesting and unusual.  It includes herb notes, along the line of fennel seed.  Sweetness is pleasant.  There are fruit tones that are hard to break down to a list; maybe along the line of dried elderberry.  The feel has an unusual dryness to it.  In the end the effect is interesting but not overly well balanced.  Drinking this brewed a little lighter will probably help it balance.  

Going back and drinking this after the other tea there is a vegetal range aspect that stands out, which is hard to describe.  It tastes a bit like when you bite into a grape seed, extended on to leaf character, so maybe like tasting a grape plant leaf or stem.

Kolkhida:  interesting!  For favoring Dian Hong most, Yunnan black tea, it's still pleasant, but not the optimum range and balance, per my preferences.  It has nice depth, and it seems to balance better, for the different layers or inputs to support each other better.  

One part is that malt tone, no longer as dominant as a singular main flavor, which again extends to bread range, or even fennel seed.  Another aspect is a savory but sweet quality, along the line of sun-dried tomato.  Mineral range is pronounced, with one part of that range coming across almost like salt; that's unusual.  I just drank a Thai version of pressed shai hong yesterday that this overlaps a good bit with, with a touch of tartness, as occurs in that tea as well.  To me it hangs together well enough.  It might evolve in character and balance even better during a third lighter infusion.

Taiguli, #3:  I'm not reaching the optimum infusion strength balance here; this is too light again.  It works like this but it's no good for ideal experience and review.  Vegetal tone eases up and warmth stands out more; it's nice.  It's not my favorite black tea range for the set of aspects but it's fine.

Kolkhida:  a wine-like character picks up, entering in where sundried tomato and some berry left off earlier.  This also isn't my absolute favorite black tea range, but it's closer.  I like these teas but it's odd not absolutely loving them.  All of the Greengold teas were so good the last round that I couldn't critique them much in terms of style, quality, or aspects range, and for these two how much someone likes either would depend on preference.  It's as if these are more experimental versions, working with different styles to make different forms of tea.  It seems like the first, the Taiguli version, is backed off in terms of oxidation level.

Taiguli, #4:  the best this has been; that's a good sign, that it evolves positively, even though it's also about just getting an infusion strength balance right.  Warm and sweet tones stand out the most so far, with pleasant spice-like undertone.  There's a little tartness and vegetal range too.  The next infusion, #5, is even better, but these notes leave off here.

Kolkhida:  this balances better than ever too.  A higher level of sweetness is pleasant, and the mix of aspects balances better.  That sun-dried tomato savory tone really complements the rest.

One thing I'm not commenting on here is a range of weaknesses or flaws that aren't present.  If teas are truly badly made then more sourness would occur (although I suppose either of these could be interpreted as slightly sour, I just don't see it that way), or flavors could be murky, less clear.  Sweetness could be lacking, throwing off balance, or vegetal tones could be even stronger, although there is some of that in both these, just more in the Taiguli version.

Conclusion:

Good teas, interesting and pleasant, even though these aren't a direct match to my favorite black tea aspect and character preference.  I've been spoiled for drinking some amazing teas over the years, and tend to focus in on range I really love, the warm and sweet, balanced, cacao, roasted sweet potato and yam, Chinese date towards dark cherry fruit in Dian Hong and related style versions.  Vegetal range and tartness doesn't come up much, in what I tend to drink.  Neither version of these was tart but one included some vegetal range.

I don't see any of the aspects in these as any sort of flaw, just normal style variations.  The quality level was quite good.  The form of malt in these varied from Chinese tea versions and Assam, for example, closer to one Chinese tea version in one case but still a little different.  I think I might have really loved their oolongs better earlier on, and for being surprised at how good all the teas were I might have built up an unreasonable expectation from memory, expecting all of them to match the best of any teas made anywhere.  These were good, pleasant and distinctive, but they don't change everything for me related to tea experience.

It's an interesting start, and there are many more samples to get to, again shared by Nika of Greengold.  I expect that character of most others will be as good or better, and that many will match my main aspect preferences even better.

on a ridgeline hike, again

Hanauma Bay, a wonderful nature preserve and snorkeling area

sunset at the beach; in Waikiki, near our small apartment

Four-day fasting update; cooking while fasting, home-made Gatorade

I posted about a recent planned 5 day fast in a Reddit fasting sub, cut short to 4 days, which I'll also share here as an update.  The part about making a variation of Gatorade to make the electrolytes more pleasant (sodium and potassium salts) was interesting to me.

It's not a new theme, trying out tisane blends during fasting, but this worked better than earlier attempts. I used lime from the garden, about a quarter of a normal size lime worth, since they were tiny, and stevia for sweetness, along with a bit of jasmine green tea. Then I mixed some of the nasty salt water I've been drinking with that, and it was fine, actually delicious. I drank most of that salt water the normal way though, just working through it.

they're an unusual variation of a lime, maybe even a small type of orange

The first and second days were easier than ever, with less experience of hunger than before. Really that was true of the 3rd through 5th fasts, just in a different sense. Energy level and productivity at work didn't seem disrupted at all (I started on a Thursday, so the crux would be over the weekend). On-site office work ran late on Friday, and I didn't get out until 7, and it was fine.

There isn't much for approach or hacks to pass on. I drank electrolytes without monitoring amounts over the first two days, which is not ideal, just mixing some Less Salt and salt into water a few times a day, and taking magnesium capsules. It's better to figure out how much sodium, potassium, and magnesium intake works for you and mix up a daily drink mix, it's just easier to carry a bit of salt to work than the liquid. I had a calf cramp in the night after the second day; I was probably a little low on potassium, so I went back to a measured approach the next morning.

For me the middle range of electrolytes seems to work out, based on the sodium and potassium recommendations in that Reddit fasting sub reference, just over 2 grams each, with sodium slightly higher. For magnesium taking a supplement pill in the morning and evening seems to work well, adding up to more than they recommend there, but not a crazy amount.

I only drank that one tisane the whole time, that one I thought of as a variation of Gatorade, but perhaps it wasn't that close.  Some people would avoid anything but water and the salts, to really lean into the detox theme, but to me drinking some tisane / herb tea is fine, surely not all that impactful or toxic.  It's a helpful way to be able to experience "eating" something, to settle your stomach, and it helps with reminding you to stay hydrated, versus drinking liters of plain water a day.

For tea I drank shou pu'er in the morning on the first three days, a bit of green tea and tisanes at work the second day, and aged white tea, shou mei, on the last day.  Not lots of any of those teas either; one Western brewing round's worth of shou I split over two days of brewing.

I can do light exercise while fasting, and walked about 3km / 1 1/2 miles as part of a commute on the second day.  In general I limit jogging to 2 miles, nowhere near a routine run, but I was so busy with other things that I didn't run.

I cooked during the fast; that was odd.  On two different days too, making up food to bring to a set of cousins who are in poor health.  I made chicken and dumpling soup, home-made meatballs and spaghetti, and lots of steamed vegetables.  

I ended up going to a grocery store two days in a row, and a bakery on one of them; it's as well to not be around food that much, if it works out not to.  I cooked so much that my mother-in-law and I can eat that for a few days too.  Of course it increased my hunger level some, and I think my stomach producing more digestive fluids came with another odd side effect the next day, as something to expel.  Fasting can be strange like that though, the odd extra body function here or there.

It went great.  The main story line, to me, was being able to stay ridiculously busy and productive while not eating for four days, and feeling mostly normal while doing it.

Why even fast?  I've covered all that in a half dozen earlier update posts.  It's not to lose weight; I didn't weigh myself, and we don't have a scale at our house.  There are lots of likely health benefits, especially related to reducing diabetes risk, eliminating fat content in internal organs, and between them, and offsetting cancer and other risks, through the process of autophagy, your body recycling and using inactive cells for an energy source.  I'm not absolutely convinced it works as promoted, because accounts of all that seem to stop short of research findings about that process, but it probably is quite healthy for you.

It also works as a diet reset.  My diet is pretty good, so there's only so much change to be made, but I think that's probably the main potential benefit for most people.  You can easily recognize when eating habits only relate to triggers, or habitual patterns, and it stands out when genuine hunger cues drive the process instead.  

You are hungry the whole time during a multi-day fast, to an extent, but it's a different form of hunger, more just feeling empty, and I'm talking more about relationship with foods and eating than just that one part.  Fasting helps you reset approach to diet, and eating habits, in ways that are hard to describe.  Or you can go right back to eating junk all the time, but it gives you that short window of opportunity to make a limited amount of changes.

I think fasting helps with my mental clarity, but that part can be vague, and people might seem to experience whatever they expect to.  When people describe how pleasant fasting can be, experiencing unusual clarity and euphoria, I can't really relate to all that, but I think I am slightly clearer mentally as a result, afterwards and even during the fast.

back to my normal diet!  jk; this place is new in Bangkok.

the latest theme is travel; I'll get back to that

Lead exposure risk in tea

 

This subject came up in a couple of different forms recently, so I looked it up, how much risk there is from lead exposure in tea.  Of course I'm not representing this as developed and conclusive research; I read a half dozen references, and this passes on the most interesting content from that.

Two studies of Chinese tea (one pu'er, one general) and one of tea in Britain, which probably relates more to teas produced in India, Sri Lanka, and Kenya, were all really consistent.  Lead exposure in tea might relate to an average of 2+ mg / kg of dry leaf, across all those categories.  Is that a lot; is it safe?  I'm still not completely sure, but all three said that's fine, just normal limited food exposure.  

One study passed on findings related to what that works out to in brewed tea, just not in as complete a form as would be more informative.  That said that half the brewed samples were below the threshold range, but didn't offer an average or distribution of the rest.

I'll mention the studies and references, summarize what I took them to mean, and cite a relevant selection that covers that.  A more in-depth review would continue on to a closer read of a dozen or so good references; this type of fast review isn't very reliable.  I only wanted to get an idea of general level of likely risk, and I think this gets you that, but the confidence of complete results is not there.

Contents of fluoride, lead, copper, chromium, arsenic and cadmium in Chinese Pu-erh tea (2012)

Very interesting; this is basically what I was looking for.  I looked up when the Chinese government banned use of lead in gasoline, since that's going to be a factor, and that was in 2000.  Another reference, which I'll get to, said that beyond that (generally earlier input) use of coal also amounted to a considerable input factor, and Chinese production of electricity from coal probably increased quite a bit from 2012 to today.  

On to considering a relevant citation:

In order to assess safety for consumers and the levels of contamination in Pu-erh tea, the authors studied the contents of fluoride, lead, copper, chromium, arsenic and cadmium in 56 Chinese samples of Pu-erh tea collected from Dali City, Lincang City, Xishuangbanna City, Simao City and Dehong City in Yunnan province. 

The ranges obtained for the elements analyzed were 80.2–151.6 mg kg− 1 (fluoride), 0.66–4.66 mg kg− 1 (lead), 14.8–19.3 mg kg− 1 (copper), 1.95–4.98 mg kg− 1 (chromium), 0.07–0.25 mg kg− 1 (arsenic) and 0.023–0.130 mg kg− 1 (cadmium). The mean leached analyte concentrations in tea infusion were 523.86 μg L− 1 for fluoride, 5.70 μg L− 1 for lead, 43.18 μg L− 1 for copper, 13.67 μg L− 1 for chromium, 0.43 μg L− 1 for arsenic and 0.17 μg L− 1 for cadmium after the tea leaves were brewed twice with boil water in a ratio of 1 g/50 ml for 5 min. The mean dissolving rates of fluoride, lead, copper, chromium, arsenic, and cadmium were 45.8%, 24.6%, 26.2%, 35.2%, 30.8% and 27.4%, respectively. 

Lots more there to cover than I'll discuss.  Note the average finding range I mentioned, 2 mg lead / kg tea, is expressed here as a findings range of .66-4.66 mg / kg, not a complete match.  Their conclusion:

Based on a 70 kg individual consuming 15 g of Pu-erh tea daily or 105 g Pu-erh tea weekly, the dietary intake of the studied elements was below the safe limits recommended by various authorities. This suggested that under the current dietary intake, there are no possible health risks to Pu-erh tea drinking consumers.

Since there is no safe level of exposure to lead (per another reference I'll cite later) "no possible health risks" seems a little strong, but I get what they're saying, that limited food exposure happens, so a normal and low range is regarded as conventional and acceptable.  Is 5 μg (per liter) a really low amount?  I never really do settle that.  It's not easy to find an acceptable low limit for lead exposure since the EPA and such say people should avoid any, and then don't want to move on to state acceptable exposure levels, even though it's going to come up.

Note that I've written separately about fluoride here.  That's still being added to municipal water in a lot of places; it's only really a contaminant and a health risk within a certain dosage range, which I won't go further into here, beyond saying that scanning that post (really the other earlier one that goes into more detail) 10 mg / day comes up as an earlier recommended adult limit, later dropped to more like half that.  I think this 523 μg / liter works out to .5 mg; not much.  In that post I state that "the treatment level of fluoride (added to municipal water) is .7 to 1.2 mg / liter," of course citing references, so that brewed tea fluoride level is just below treated water level.  On the high side two liters of brewed tea from treated water might contain 3.4 mg then; not above the limit, but high enough, and getting there.

Back to the next reference and considering lead instead.

Accumulation of potentially toxic elements in Chinese tea (Camellia sinensis): Towards source apportionment and health risk assessment  (2022)

Tea (Camellia sinensis) is a popular beverage that is consumed globally. However, a better understanding of potentially toxic elements (PTEs) content in tea leaves and infusion is necessary to minimize risk on human health. Therefore, 249 tea samples (grown in different areas) covering six types of tea were collected in China to investigate the PTEs contents, identify their potential source and assess the health risk associated with drinking tea. 

PTE contents in tea leaves across six tea types were ND–0.900 (Cd), 0.005–2.133 (As), ND–5.679 (Pb), ND–13.86 (Cr), 1.601–22.93 (Ni), ND–2.048 (Se), 0.109–622.4 (F), 13.02–269.9 (Rb), 1.845–50.88 (Sr), and 2.796–53.23 (Ba) mg/kg. The result of tea infusion showed that 14.3 %–44.1 % (green tea), 14.5 %–46.7 % (black tea), 10.5 %–25.3 % (dark tea), 13.6 %–34.2 % (oolong tea), 16.9 %–40.7 % (yellow tea), and 19.9 %–35.1 % (white tea) of F were released. All tea types, except green tea, exhibited comparatively low leachability of Cd, As, Pb and Cr in tea infusion. 

The source apportionment revealed that PTEs in tea leaves mainly originated from soil parental materials, while industrial activities, fertilizer application, and manufacturing processes may contribute to exogenous Se, Cd, As, and Cr accumulation. Health risk assessment indicated that F in tea infusion dominated the health risk. 

It's interesting that a relatively similar finding for fluoride level, as in the earlier study, was identified as a potential health risk, while it wasn't earlier.  That earlier study identified an average of 80 to 150 mg / kg Fluoride and this a range of .1 to 644 (so four times higher on the high end, but negligible on the low side).

Here the lead range is not detectable to 5.7 mg / kg of dry leaf; a little higher top range, but similar (the other was 0.66–4.66 mg / kg (lead).  Extraction rate was 24.6% in the last study for lead (just mentioned as low here), but we're still back to considering if the earlier exposure level was ok or not (5.70 μg / liter for lead).  It sounds low, but really a second review of food exposure levels would really help place that, and I didn't get to that here.  

Google does offer this, as a starting point:

What are the maximum levels for lead in certain food categories?

Heavy metals

The maximum allowed lead content ranges from 0.01 mg/kg in some baby foods to 3 mg/kg in food supplements. Most meat products, fats, and oils should not contain more than 0.1 mg/kg of lead, while the limits for fruit, vegetables, and fungi vary between 0.1 mg/kg and 0.8 mg/kg.Jun 4, 2566 BE

.1 mg would be 100 micrograms; that's a good bit in comparison to what's turning up here.  It's necessary to note that I'm switching around between dosage level per liter and amount per kg; it takes awhile to brew up a kg of tea, and that 24% extraction rate is positive (versus that being higher).  If you eat a kg of lettuce presumably that .1 to .8 mg--100 to 800 μg--goes right into you.  That's a lot of lettuce, but nothing like brewing 1000 grams of tea 5 to 8 grams at a time.

Analyses of lead levels in tea (seemingly from a 2014 review)

This study was carried out to address the urgent need to gather more data on levels of lead (Pb) in tea, to inform current EU discussions on a proposed maximum limit of 1 mg/kg Pb in tea (‘dried leaves and stalks, fermented or otherwise of Camellia sinensis’).

Levels of Pb were quantified in 51 samples of black and green tea leaves.These samples were also analysed as tea liquid (drink), after steeping the tea leaves for both a shorter and a longer brew time, following an agreed protocol. 11 different varieties of dried tea (including a white tea) from different tea growing regions were also purchased and analysed to ensure there was good geographic and tea-type coverage.

Note that the tested range went way beyond that considered 1 mg / kg limit in those other studies, up to 4.6 and 5.7 mg / kg.

The study findings showed that the levels of lead in the 51 samples of dried tea varied significantly and ranged from 0.125 to 2.56 mg/kg.

The levels of lead found in the brewed teas were very low with half the results being less than the limit of detection 0.2µg/L (1 µg/L=0.001mg/kg).

Teas brewed for a longer period of time resulted in only a slightly higher level of lead.

The levels of lead found in the additional 11 dry teas ranged from 0.177 to 1.96 mg/kg.

Exposure to lead from the consumption of the brewed teas as tested is not considered to be of concern for consumer health compared to normal levels of exposure to lead from all dietary sources. 

They were one stat away from expressing clear findings, identifying the brewed tea lead levels and an average across the samples for that range.  It's a lot to go through just to say "it was low" at the end.  The paper itself (linked there; that's just a summary) goes further:

Two samples contained Pb levels above 1 µg/L and the highest level, 2 µg/L, was found in a sample of green tea (Chinese Sencha).

Ok then, three samples ranged at or above 1 µg/L, out of 51, which is still low, based on input from the other papers.

Presumably the conclusion here is that a 1 mg / kg dry tea lead level isn't the right threshold limit, and 2 or 2 1/2 is still no problem (relating back to considering 1 mg / kg as an import level limit).

In China, where is the lead contamination coming from?

Initially I was concerned that leaded gasoline might be an issue, but this reviewed identified that was banned in 2000 (so it's surely not being produced or sold in China now, right?).  It's an odd starting point but this is how they open that:

It is common to use effluent as a fertiliser in China. This results in accumulation over time, within fields, of heavy metals.- cadmium, chromium, copper, nickel, lead and zinc (Cd, Cr, Cu, Ni, Pb and Zn).

Interesting!  A lot of the paper is about lead contamination in water sources, presumably from a number of industrial waste sources, natural sources, or from coal use, as described further:

Lead can be emitted during the mining and smelting of mercury ores, because most such ores also contain lead. Lead is also emitted during the burning of coal. Researchers in Guizhou province, where there are 12 large mercury mining and smelting operations and heavy coal-powered industry, found that rice accounted for 94-96% of the uptake of methyl mercury (Raloff, 2010). They were not testing for lead, but it is likely that the rice was also a source of lead in the diet...

...What the evidence from water catchments in the more industrialised parts of the China shows is that there is a clear link between lead contamination of the environment and industrial activity. Coal use in China is rising steadily and it should be noted that coal naturally contains lead.

Tea gardens would surely never water plants from the Yangtze river, or other polluted sources, but I suppose airborne lead exposure is probably a concern.

WHO guidance to reduce illness due to lead exposure

I never did find much guidance on safe lead exposure limits or relative risk of exposure but this is a start:

The WHO Guideline for Clinical Management of Exposure to Lead recommends a  blood lead concentration of 5 micrograms per decilitre (μg/dL) as a trigger for a thorough review of the ways in which a person is being exposed to lead and for action to reduce or end this exposure.

With 1 in 3 children estimated to have blood lead levels in excess of the 5μg/dL threshold[1], according to the United Nations Children’s Fund (UNICEF)...

“There is no known safe level of lead in the human body. The new guideline will help the diagnosis and treatment of lead exposure for individual patients and help health workers tackle mass poisoning incidents,” said Lesley Onyon, Scientist, Chemical Safety and Health Unit.

This covers more on general effects and risk sources:

Lead in the body affects practically all organ systems, travelling to the brain, liver and kidney and accumulating in the teeth and bones, where it can last decades and move from bones back into the blood during pregnancy, exposing the developing foetus.

It is still widespread owing to current and past use of the metal and its salts, most commonly in storage batteries, ammunition, pipes (including those used for water supply) and in alloys such as solder, pigments, paints, glazes, plastics and even some traditional medicines, cosmetics and spices.

Lead was once used extensively in petrol additives, but this has recently been banned in all countries in the world. But in many popular uses, particularly lead in paint, remain although alternatives are known and available. 

Framed this way it sounds like more of a "developing world" issue than related to standard risks.  I'm still a little concerned about those food exposure levels; surely that's not a complete non-issue, even if lead pipes, paint, glazes, and cosmetics may pose more risk, when that's not carefully controlled.

Another reference says more about lead exposure risk and effects, but I won't go further with that, only mentioning it here for those still interested in going further:

Lead toxicity: a review

Tea seems to only pose a very limited lead exposure risk, in general, although I guess there could always be exceptions.  

I don't love the idea of consuming 5 µg / liter, even if I still don't feel like I can place what that means.  At least the teas tested in the British samples study identified 48 out of 51 with levels below 1 µg / liter, two samples around 1 microgram and one at 2, and half below the testing threshold of .2 µg / liter.

So we should probably "use trusted tea sources?"  That's always a little problematic, isn't it?  At least the worst case doesn't sound so bad.  It makes you wonder how bad food risk is, if this is all on the low side compared to that.