"Can Vitamin C Help with Lead Poisoning?"
“Even if a nutritional manipulation is proven effective
in reducing blood lead levels, a reliance on such an intervention
places most of the burden for prevention
on those most affected and least responsible
for the underlying environmental causes….
Nutritional interventions, therefore, must never substitute for efforts
to reduce lead exposure to safer levels.
On the other hand, when used as an adjunct…,
some nutritional changes may prove to have benefits beyond…lead toxicity.”
For example, vitamin C rich foods may help
with a bunch of things in addition to perhaps influencing lead toxicity
through an effect on absorption of lead, elimination of lead,
transport within the body, tissue binding,
or just helping ameliorate some of the damage.
But based on what?
Well, in 1939, a remarkable study was published,
entitled "Vitamin C Treatment in Lead Poisoning",
in which 17 lead workers were given 100mg of vitamin C a day,
the amount found in 1 or 2 oranges,
and “with practically all of them, there was a marked gain in vigor,
color of skin, cheerfulness,their blood, appetite, and ability to sleep….”
They were chosen because they seemed in pretty bad shape,
maybe even had scurvy;
so, no wonder a little vitamin C helped.
But vitamin C is an antioxidant, and oxidation is
“an important mechanism underlying lead toxicity”;
so, it’s conceivable that it may have mediated some of the harm,
but the vitamin C didn’t appear to just reduce the damage from the lead,
but reduced the lead itself.
This is the amount of lead a painter was peeing out
over a month after starting 200mg of vitamin C a day,
a five-fold drop, suggesting he was absorbing less
of the lead into his body,
and he was one of three painters they tried it on,
and evidently all their levels dropped.
The researchers concluded that those exposed to lead should be advised
to include in their diet plenty of vitamin C rich foods,
such as tomatoes, citrus, spinach, turnips, bell peppers, cantaloupe, etc.
Now, this was just 3 painters, and they didn’t have a control group
of painters that didn’t take vitamin C.
So, maybe everyone’s lead levels would have dropped regardless,
for some reason, or it was just a coincidence.
You don’t know until you put it to the test.
That original data was so compelling that it inspired others
to try to replicate them.
I mean, if it actually worked, they could start handing out
grapefruits at the factory door.
The earlier study didn’t have a good control group,
but they weren’t going to make that same mistake this time.
Half the group got 100mg of vitamin C a day,
not just for a month but for a year,
the other group got nothing,
and careful study of the group failed to reveal
any effect of vitamin C on the lead concentration
in their blood or urine.
No difference in their physical condition,
no changes in their blood work;
and so, no reason for recommending the use of vitamin C
to minimize effects of lead absorption.
Bummer.
Oh, it looked so promising.
Whenever I study a topic, I try to read the research chronologically,
so as to experience the discoveries as they happened throughout history,
but I was so tempted at this point to just jump
to a recent review to see what had happened
in the intervening 74 years since this was published,
but I didn’t want to spoiler alert myself.
There were in vitro studies where they dripped antioxidants
on lead exposed cells, and it seemed to help.
So, they jumped on the cantaloupe bandwagon too,
but these were test tube studies.
The first population study was published in 1999,
and they did find that those with high vitamin C levels
in their blood tended to have lower lead levels.
Youths with the highest vitamin C levels had a nearly 90% lower
prevalence of having elevated blood lead levels
compared to those with the lowest C.
Now, this was a cross-sectional study, just a snapshot in time;
so, we don’t know if the vitamin C caused a drop in lead –
maybe the lead caused a drop in vitamin C.
Lead is a pro-oxidant;
so, maybe it just ate up the vitamin C.
And hey, who has higher vitamin C levels?
Those who can afford to have higher vitamin C levels,
those who eat lots of fruits and vegetables.
Maybe the lower vitamin C levels was just a proxy for being poor,
and that’s the real reason for their higher lead levels.
There's lots of good reasons to be eating more fruits and vegetables,
and we should be eating more spinach regardless,
but it would be nice to know if it actually helps with lead poisoning or not.
To know that, we need to put it to the test.
Unfortunately, most of the published interventions are like this:
What are the effects of dietary vitamin C supplementation
on lead-treated sea cucumbers?
Well, that’s not very helpful.
And, there’s a surprising number of articles
on the effects of C supplementation on mouse testicles,
but that’s because lead may impair male fertility.
Lead workers appear to have a reduced likelihood of fathering children.
This may in part be due to oxidative stress;
so, how about giving an antioxidant, like vitamin C,
and putting it to the testes?
No, not rat testes.
No, not frog testes.
No, not crab testes.
(I didn’t even know crabs had testicles).
Here we go, the clinical relevance of vitamin C
among lead-exposed infertile men—human men,
which I’ll cover, next.