What Do We Know About Lead

This keeps coming up, unfortunately, so I want to write down all I can so I can contextualize the next Thing about lead I see.

How much is ok

If you sent me an article about a new contaminant, the first few things I’d ask would be: 1. Are we sure it’s bad for you? 2. In what ways is it bad for you, and do I care? 3. Is there any threshold below which it doesn’t matter? (e.g. your body flushes out N mg/day)

Because we might be able to avoid worrying about the whole thing! Unfortunately, with lead, it’s definitely bad for you in a zillion ways, and there is No Safe Level Of Lead.

aside: the “no safe level” slogan kinda sucks

It’s great that Needleman and them did all this research, and at the time, “no safe level” pointed people in the right direction. We were not worried enough about lead, so an absolutist scary phrase was valuable. However, as with (almost?) all absolutist scary phrases, it’s not really true. For example: one picogram per liter is fine! You won’t even notice it. And those who are paying attention to lead nowadays are the ones who least need to hear about it, so an absolutist scary phrase is no longer the right messaging. So it goes.

Anyway, since we can’t get away easy, let’s learn what levels matter. Some important numbers:

No, you know what, screw this, and screw Consumer Reports

I was going to write a comprehensive “everything I know about lead”, but 1. no time, 2. let me be honest about why I want to write this. The most recent Thing about Lead was this post, “Protein Powders and Shakes contain High Levels of Lead”, and I am now pivoting this blog post to tear into CR instead.

I read CR’s post and thought, oh gosh, all the protein powders unsafe! Orgain (not one of the worst offenders) is 143% of “CR’s Level of Concern”! Optimum Gold Standard is 56%! Am I going to give myself lead poisoning if I drink two of these a day? Or will the net benefit from extra protein give me extra muscles and protect me in my old age? AND, if I have to worry about brands, how do I fit this dimension in with all the other dimensions (taste, saturated fat, animal welfare, etc) while trying to make decisions here?

No, look, it’s fine, CR is just another part of the ragefear machine that is the internet today. Here are CR’s sins in this article:

The MADL of 0.5 ug/day

Knowing there is “no safe level” of lead, and yet we have to proceed and live our lives, how does one contextualize any amount of lead? How do we choose “how much is enough”?

This level is based on the California Prop 65 maximum allowable dose level (MADL) for lead—0.5 micrograms per day—which has a wide safety margin built in. “We use this value because it is the most protective lead standard available,” says Sana Mujahid, PhD, who oversees food safety research and testing at CR.

They are literally are using 0.5 ug because it’s the lowest number they can find! It gives them the most eye-catching headlines! To take Naked Nutrition Mass Gainer as an example: 7.7ug of lead is not great, but “Naked Nutrition has 1572% of CR’s level of concern for lead” sounds a lot worse than “Naked Nutrition has 87% of the FDA reference level”.

(I guess as a former Californian, the mere mention of Prop 65 should have set off my alarm bells. Or rather, it should have silenced my overactive alarm bells.)

The serving sizes

Naked Nutrition Mass Gainer is the big outlier here because it’s 10 times as big as the others! The serving size is 321g/1250 calories! Again, 7ug is still bad, but put these things in context; nobody’s switching from 30g of Optimum Gold Standard Whey to 321g of Naked Nutrition Mass Gainer. Good grief.

Carelessness or malpractice

Remember this from above: “1.7-5.3 ug/day: estimated mean daily exposure to lead for adults by a 2019 study”

The dingdongs at Consumer Reports reported this 1.7-5.3 ug as “5.3 ug.” Until I found this source study, I was reading their post with an open mind, but once I realized they are committing this kind of carelessness or statistical malpractice in one place, I have no idea how much they are in other places.

What should this story say?

EDIT: I am even more confused

All of these tested products are in the 0.25-7 ug range. (and the worst offenders, Naked and Huel have conflicting test reports, so who knows, maybe they’re not that bad.)

But the background intake matters so much! Let’s say the “good” powders have 0.25ug lead and the “bad” ones have, idk, 3ug. I now don’t know how bad 3ug is! If our background level is 20-80ug, it’s no big deal; if it’s 1-5ug, that is a big deal!

I will say: Huel only citing 20-80ug feels disingenuous. But Consumer Reports citing 1.7-5.3ug as 5.3, and then writing their whole article comparing to 0.5, which is fantasy la-la land (aka CA Prop 65), is even worse.

EDIT EDIT: I keep getting sucked into this thing. And, screw Huel too

Ok, after a day I think I am more convinced that most people eat <10ug lead in a day, that Huel is cherry-picking data, but the CR article still sucks.

Huel claim 1

Huel claims that a normal meal of “sausages, potatoes, and vegetables” has 5ug lead, pointing to this source.

I tried to make a meal that added up to 5ug lead, and it was kind of hard, unless I included cabbage. Cabbage is listed there as 37ug/kg lead, so we could imagine a meal of:

total: 4.9ug. It’s pretty hard otherwise. All foods higher than 1ug/100g:

That’s it. Everything else is less than 1ug/100g. So it’s not impossible to make a meal of 5ug lead, but it’s certainly not “the typical meal.”

Huel claim 2

Huel claims “most adults naturally consume 20 to 80 µg per day through everyday foods”. They link to this study (Europe, 2010), which does suggest adults consume 20-80ug per day.

But there’s also this study (US, 2019, from 2014-16 data), which says adults consume 1.7-5.3ug.

Earlier I said “I don’t know, could be either!” but now, after looking at Huel Claim 1 and the UK Total Diet Study, I think it’s really hard to claim adults eat 20-80 ug/day. Most foods were in the 2-6 ug/kg range (table 5) so, imagining eating about 2kg of food in a day, that’s 4-12ug lead. If you eat some cabbage, maybe 7-15. 20 is possible, “20-80” isn’t.

It may also be that the US has less lead than Europe or that the 5+ years between these studies made a difference. At any rate, uncritically reporting 20-80ug feels cherry-picked.

Measurement error too

Ben Shindel, who did lead testing himself for years, wrote about more problems with the CR article, and it’s worth pointing out: these measurements are quite variable; finding 6ug in one batch of Huel and 0.5ug in Optimum Nutrition might very well be the luck based on the batches you happened to test. (We don’t even know how many!)

This also explains why Huel and Naked’s internal testing show <2ug while CR’s shows them at 6 and 7; variance happens.

(This also means the big UK Total Diet Study must be riddled with measurement error too! It doesn’t change the conclusion I drew from it (that it’s hard to get 5ug per meal), though, unless the errors are correlated, and I don’t yet see any reason to believe that)

So now what

Here’s what I think now:

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