- There it is.
This is iron, and iron is what's called a heavy metal.
And it's added to cereal on purpose, which people were freaking out
about on TikTok a few months back. And I kind of get why.
I mean, heavy metals have a reputation for being dangerous or unhealthy.
- Some popular fruit juices may contain heavy metal.
- Many baby foods have dangerous levels of toxic heavy metals.
- And if this were a heavy metal like lead or mercury, it would be a huge problem.
So why is it that some heavy metals make you sick or even kill you,
but others, you can just eat?
♫ Chime Sound Effect ♫
Alright, let's get into this.
First off, heavy metals are heavy because they have a high atomic mass and density.
And despite their reputation, they're not all bad.
You can put them on a "necessary to keep you alive", to "will kill" you spectrum
which total disclaimer is not exact.
There's a lot of variability here, depending on
how much of a heavy metal we're talking about,
what other elements it might be combined with.
You get it.
But let's start in the middle with gold.
Elemental gold, what's in gold leaf, is inert.
Meaning it's generally not going to react with other stuff like oxygen in the air or
acid in your stomach. That's why a lot of jewelry is made out of gold. It won't get discolored or
rusty like a bunch of other metals do. The fact that it's inert is also why you can eat it.
[ inaudible ]
I probably should have done this shot last.
Your body can't digest it, so it'll just
pass right on through.
But keep in mind that the gold leaf I ate was 24-karats.
Karats is the measurement of the proportion of gold out of 24 parts total.
So what I ate was pure gold.
18 karat gold is only 18 out of 24 parts gold. So six of the 24 parts are other
metals like nickel or copper, which do react with stuff. And that could be a problem.
So that's the heavy metal gold. Heavy metals like mercury and lead are a totally different story.
In the case of lead, our brains will mistake it for calcium, and that's bad. Your brain needs
calcium to send messages between neurons. So lead competing with calcium can mean two major things.
The calcium that should be getting into your neurons and triggering that message isn't,
or neurons that aren't supposed to be active start randomly sending messages. Too much or
too little signaling in your brain can make it harder for you to process information and cause
a bunch of behavioral changes.
By the way, there's some speculation that those behavioral changes
are part of what brought down the Roman Empire. But that's another video altogether.
Now, as for mercury, it comes in a few different forms, and organic mercury, when it's combined
with carbon, is the most toxic. In part because it can soak right through your skin.
You've probably eaten organic mercury before in seafood, in the form of methylmercury.
But in that case, it's in such small amounts that you don't really need to worry about it,
at least not in the short term.
But when you're exposed to organic mercury in larger amounts, all at once,
it can be really, really bad. And there's a story about just that that has always stuck with me.
In August 1996, a chemistry professor at Dartmouth named Karen Wetterhahn was in
the lab doing research, and she spilled a few drops of dimethylmercury onto her latex glove.
A glove similar to this one.
She wasn't worried because she was taking what were at the time,
considered the right safety precautions.
What people didn't realize was that dimethylmercury can soak
through latex gloves — to your skin — in something like 15 seconds.
Fast forward, a few months later, and Dr. Wetterhahn is really sick. She's experiencing
a bunch of different neurological symptoms, like losing her balance and slurring her
words. And not long after, she falls into a coma. Dr. Wetterhahn died in June 1997,
less than a year after first spilling dimethylmercury on her glove.
Those neurological symptoms she was experiencing make sense because mercury accumulates in your
central nervous system, including your brain. The only way to remove mercury is through something
called chelation therapy, where you're given a drug that can bind to metals in your blood.
Even though Dr. Wetterhahn was given chelation therapy, it was a few months after her exposure.
And so, her health continued to rapidly deteriorate. Today, people working with
organic mercury are told to wear multiple pairs of gloves that it can't soak through.
Now let's go back to the beginning and talk about a heavy metal that you need, iron.
Iron is a heavy metal but also an essential nutrient. It's so essential that
we need it to breathe. So in your red blood cells, you have a protein called hemoglobin
that carries oxygen throughout your body. In hemoglobin, there are molecules called heme
that use iron to bind oxygen molecules. No iron means no oxygen flowing throughout your body.
In 1941, companies started adding elemental iron and some other essential nutrients to
cereals and other grain products. That's what the word fortified refers to. And obviously,
they're still fortifying grain products today. I mean, I just pulled iron out of my cereal.
But what's interesting is that elemental iron powder has a low bioavailability,
meaning your body can't actually absorb and use most of it. There are chemists working on
changing that, but TBD on when and if that change might happen. So heavy metals can be good for you,
but also deadly, but also somewhere in between.
So I have some news to share. This is actually my last video for Reactions.
The past two and a half years of writing and hosting this show have been
a ton of fun and also sometimes challenging, especially when a pandemic hit, and we needed
to adapt almost instantly. I'm going to miss this amazing team of producers that I've worked with
and who have become my friends. And I'll miss all of you giving us really awesome,
sometimes unique feedback that's truly helpful and also makes us laugh sometimes.
But I'm excited to be starting something new, a podcast from the American Chemical Society called
Tiny Matters. It's about things that are small in size but big in impact. And I think you're
going to like it. We just released our trailer, and I've left a link to it in the description.
If you can subscribe, rate, and review, that's how it'll get on the charts and that people
will be able to learn about it. I would be incredibly grateful to get your support.
And although I won't be a part of it, the Reactions team still has a whole lot more
in store for you. And I know I can't wait to see the new videos they put out.
Thanks, everyone.