Adult Exposure to Lead

“Children in approximately 4 million households in the United States are being exposed to high levels of lead.” As I discuss in my video The Effects of Low-Level Lead Exposure in Adults, “Despite the dramatic decline in children’s blood-lead concentrations over the decades, lead toxicity remains a major public health problem”—and not just for children. Yes, lead is “a devastating neurotoxin,” with learning disabilities and attention deficits in children beginning around blood lead levels of 10 mg/dL, which is when you start seeing high blood pressure and nerve damage in adults, as you can see at 0:41 in my video. But, the blood levels in American adults these days are down around 1 mg/dL, not 10 mg/dL, unless you work or play in an indoor firing range, where the lead levels in the air are so high that more than half of recreational target shooters have levels over 10 mg/dL or even 25 mg/dL.

In fact, even open-air outdoor ranges can be a problem. Spending just two days a month at such a range may quadruple blood lead levels and push them up into the danger zone. What if you don’t use firearms yourself but live in a house with someone who does? The lead levels can be so high that the Centers for Disease Control and Prevention advises those who go to shooting ranges to take “measures to prevent take-home exposure including showering and changing into clean clothes after shooting…, storing clean clothes in a separate bin from contaminated clothing, laundering of non disposable outer protective clothing…and leaving at the range shoes worn inside the firing range,” among other actions. Even if none of that applies and your blood levels are under 10 mg/dL, there is still some evidence of increased risk of hand tremors, high blood pressure, kidney damage, and other issues, as you can see at 1:44 in my video. But what if you’re down around a blood lead level of 1 mg/dL, like most people?

“Blood lead levels in the range currently considered acceptable are associated with increased prevalence of gout,” a painful arthritis. In fact, researchers found that blood levels as low as approximately 1.2 mg/dL, which is close to the current American average, can be associated with increased prevalence of gout. So, this means that “very low levels of lead may still be associated with health risks,” suggesting “there is no such thing as a ‘safe’ level of exposure to lead.”

Where is the lead even coming from? Lead only circulates in the body for about a month, so if you have lead in your bloodstream, it’s from some ongoing exposure. Most adults don’t eat peeling paint chips, though, and autos aren’t fueled by leaded gas anymore. There are specific foods, supplements, and cosmetics that are contaminated with lead (and I have videos on all those topics), but for most adults, the source of ongoing lead exposure is from our own skeleton. I just mentioned that lead only circulates in the body for about a month. Well, where does it go after that? It can get deposited in our bones. “More than 90% of the total body lead content resides in the bone, where the half-life is decades long,” not just a month. So, half or more of the lead in our blood represents lead from past exposures just now leaching out of our bones back into our bloodstream, and this “gradual release of lead from the bone serves as a persistent source of toxicity long after cessation of external exposure,” that is, long after leaded gasoline was removed from the pumps for those of us that who were around back before the 1980s.

So, the answer to where the lead comes from is like Pogo’s We’ve met the enemy and he is us or that classic horror movie scene where the call is coming from inside the house.

The amount of lead in our bones can actually be measured, and research shows higher levels are associated with some of our leading causes of death and disability, from tooth decay and miscarriages to cognitive decline and cataracts. “Much of the lead found in adults today was deposited decades ago. Thus, regulations enacted in the 1970s were too late” for many of us, but at least things are going in the right direction now. The “dramatic societal decreases” in blood lead in the United States since the 1970s have been associated with a four- to five-point increase in the average IQs of American adults. Given that, a “particularly provocative question is whether the whole country suffered brain damage prior to the 1980 decreases in blood lead. Was ‘the best generation’ really the brain damaged generation?”

I’m such a sucker for science documentaries, and my favorite episode of Cosmos: A Spacetime Odyssey was The Clean Room, which dealt with this very issue. Trivia: Carl Sagan was my next-door neighbor when I was at Cornell!

If you want to find out How the Leaded Gas Industry Got Away with It, check out that video. How the Lead Paint Industry Got Away with It is similarly scandalous. Lead in Drinking Water offers the modern-day tale of what happened in Flint, Michigan, and “Normal” Blood Lead Levels Can Be Toxic explores the impacts on childhood development.


I close out this extended video series on lead with information on what we can do about it:

Interested in learning more about lead being absorbed and released in our bones, and how calcium supplements may affect that process? See The Rise in Blood Lead Levels at Pregnancy and Menopause and Should Pregnant Women Take Calcium Supplements to Lower Lead Levels?.

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

 

Why You Don’t Want “Normal” Blood Lead Levels

“By the 1950s, lead—a dangerous neurotoxin that was once buried deep in the ground, far away from humans—had polluted the entire planet.” We have leaded gasoline to thank for this. It’s hard to imagine “a better strategy for maximizing population exposure to a poison than to have it emitted by a ubiquitous mobile source and to line the surfaces of dwellings” and our neighborhoods with it.

“Overall, about 5 million metric tons of lead was deposited in the environment as a result of the combustion of leaded gasoline” by our automobiles before it was regulated. A single busy street could receive more than a metric ton a year, and the lead just built up, decade after decade. Finally, thanks to regulations starting in the 1970s, we stopped spewing so much into the air. As you can see at 0:57 in my video “Normal” Blood Lead Levels Can Be Toxic, as lead use dropped, so did the levels of lead in our blood, resulting in a 98 percent reduction in the percentage of young children with elevated blood lead levels. Of course, the term “elevated” is relative.

“Prior to 1970, lead poisoning was defined by a blood lead concentration of 60 mg/dL or higher” but “since then, the blood lead concentration for defining lead toxicity gradually has been reduced” to 40 mg/dL, then 30 mg/dL, then 25 mg/dL, and then further down to 10mg/dL, as lead levels “previously thought to be safe or inconsequential for children have consistently been shown to be risk factors” for cognitive and behavioral problems.

Currently, an elevated blood lead level is considered to be more than 5 mg/dL. So, under 5 mg/dL, your lead level is considered to be non-elevated or normal. But what does having a “normal” lead level mean?

“Virtually all residents of industrialized countries have bone lead stores that are several orders of magnitude greater than those of our preindustrial ancestors.” If you go to a museum and test the lead levels of ancient skeletons buried a millennium ago, they are a thousand times lower compared to people today, “which indicates the probable existence within most Americans of dysfunctions caused by poisoning from chronic, excessive overexposures to industrial Pb lead.”

You can see a graphical representation of “body burdens of lead” in a preindustrial ancestor, a typical American citizen, and a person with overtly symptomatic lead poisoning, where he might be doubled over in pain, at 2:30 in my video. What the medical and research communities had failed to understand is that they had only concerned themselves with people with actual lead poisoning and those at “typical” lead levels, but “the new value for natural lead levels in [preindustrial] humans shows that typical levels of lead in humans are quite definitely not properly described by the term ‘very low levels’ at all, but instead constitute grossly excessive, 1000-fold over-exposure levels.”

 The bottom line? “No level of lead exposure appears to be ‘safe’ and even the current ‘low’ levels of exposure in children are associated with neurodevelopmental deficits,” including reduced IQ. It could have been a lot worse if we hadn’t started restricting leaded gas. Thanks to falling blood lead levels starting in the 1970s, preschoolers born in the 1990s were two to five IQ points higher than kids like me born before 1976. So, when we see our kids and grandkids being such wizzes at technology that it’s hard to keep up with them, a small part of that may be them not suffering as much lead-induced brain damage as we did. And, what that means for the country is potentially hundreds of billions of dollars of improved productivity because our children are less brain-damaged.

If that seems like a lot for just a few IQ points, as you can see at 4:26 in my video, what you have to realize is that even a small shift in average IQ could result in a 50 percent increase in the number of the “mentally retarded,” millions more in need of special education and services.

So, “removal of lead from gasoline in the United States has been described as one of the great public health achievements of the 20th century, but it almost did not happen.” Indeed, “tremendous pressure by the lead industry itself was brought to bear to quiet, even intimidate, researchers and clinicians who reported on or identified lead as a hazard.” Decent “scientists and health officials faced enormous opposition but never lost sight of the mandate to protect public health.”

Two of the “young, idealistic employees” at the newly formed Environmental Protection Agency, who played key roles in the fight, recount how “naïve [they were] to the ways of Washington”:

“Our youth was also used against us. Our inexperience was cited as a reason for rejecting the lead regulatory proposals….Finally, in retrospect, our youth and inexperience also helped us to succeed in taking on a billion dollar industry. We were too young to know, that regulating lead in gasoline was impossible.”


What about lead exposure after childhood? That’s the topic of my video The Effects of Low-Level Lead Exposure in Adults.

What can we do about lead exposure? See:

If you missed the first three videos in this series, check out:

For the effects of mercury, another heavy metal, see:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

How the Lead Paint and Gas Industries Got Away with It

We have known for thousands of years that lead can be toxic and for more than a century that children could be poisoned by lead paint. Since those first cases, the “lead industry has mobilized against the advances of science,” as I discuss in my video How the Lead Paint Industry Got Away with It.

By 1926, lead poisoning was already “of relatively frequent occurrence in children,” yet “the United States continued to allow the use of lead-based paint until 1978.” In contrast, in Europe, many countries said, Hmm, poisoning children? No, thanks. and “banned the use of lead-based paint as early as 1909.” 

“The delay in banning lead-based paint in the United States was due largely to the marketing and lobbying efforts of the lead industry,” profiting from the poison. It knew it couldn’t hold off forever, but the industry boasted that its “victories have been in the deferral of implementation of…regulations.”

And now, “peeling paint turns into poisonous dust,” and guess where it ends up? As a Mount Sinai dean and a Harvard neurology professor put it: “Lead is a devastating poison. It damages children’s brains, erodes intelligence, diminishes creativity…” and judgment and language. Yet, despite the accumulating evidence, the lead industry didn’t just fail to warn people—“it engaged in an energetic promotion of lead paint.” After all, a can of pure white lead paint had huge amounts of lead, which meant huge profits for the industry.

But, as you can see in an old advertisement featured at 1:55 in my video, “[t]here is no cause for worry” if your toddler rubs up against lead paint, because those “fingerprint smudges or dirt spots” can be removed “easily without harming the paint.” Wouldn’t want to harm the paint. After all, “painted walls are sanitary…”

The director of the Lead Industry Association blamed the victims: “Childhood lead poisoning is essentially a problem of slum dwellings and relatively ignorant parents.”

“It seems that no amount of evidence, no health statistics, no public outrage could get industry to care that their lead paint was killing and poisoning children,” but how much public outrage was there really?

“It goes without saying that lead is a devastating, debilitating poison” and that “literally millions of children have been diagnosed with varying degrees of elevated blood lead levels…” Compare that to polio, for example. “In the 1950s, for example, fewer than sixty thousand new cases of polio per year created a near-panic among American parents and a national mobilization that led to vaccination campaigns that virtually wiped out the disease within a decade.” In contrast, despite “many millions of children [who have] had their lives altered for the worse by exposure to lead…[a]t no point in the past hundred years has there been a similar national mobilization over lead.” Today, after literally a century, the Centers for Disease Control and Prevention estimates over five hundred thousand children still suffer from “elevated blood-lead levels.”

The good news is that blood lead levels are in decline, which is celebrated as one of our great public health achievements. But, given what we knew, and for how long we knew, “it is presumptuous to declare the decline in childhood lead poisoning a public health victory.” Indeed, “even if we were victorious…it would be a victory diminished by our failure to learn from the epidemic and take steps to dramatically reduce exposures to other confirmed and suspected environmental toxicants as well as chemicals of uncertain toxicity.”

That’s one of the reasons I wanted to do this series on lead. We need to learn from our history so the next time some industry wants to sell something to our kids, we’ll stick to the science. And, of course, lead levels aren’t declining for everyone.

As the whistle-blowing pediatrician who helped expose the Flint drinking water crisis explained, “The people in Flint have a 20-year lower life expectancy than people in a neighboring suburb. We were already struggling with every barrier to our children’s success. Then we gave them lead.”

Her research showed that the switch in water supplies from the Great Lakes to the polluted Flint River “created a perfect storm” for lead contamination, doubling the percentage of kids with elevated lead levels in their blood, as you can see at 0:42 in my video How the Leaded Gas Industry Got Away with It, whereas out in the suburbs, where the water supply remained unchanged, children’s lead levels stayed about the same. That’s how she knew it was the switch in water supplies. That’s what broke the story of the Flint crisis: a doubling of elevated lead levels.

But wait a moment: Even before the switch from Lake Huron to the polluted Flint River, when everyone was getting the same water, lead levels in children in Flint were twice that of the suburbs. There was already a doubling in elevated lead levels in Flint and other poor communities around the country, but where have all the crisis headlines been? Indeed, even with all the bottled water in the world, the children in Flint will continue to live in a lead-polluted environment.

Many have pointed out the irony that the new water from the Flint River was “so corrosive” that the nearby General Motors plant switched back to a clean water source when it started noticing rust spots on its new parts, all while water quality complaints from Flint residents were being ignored. But, there is an additional irony: General Motors is a major reason why the world is so contaminated with lead in the first place, as GM invented leaded gasoline. “Shortly after manufacture began, workers…began to become floridly psychotic and die.”

“In the wake of blaring headlines” about the lead-poisoned workers, public health leaders “warned of the potential for damage to broad swaths of the population” posed by putting this “well established toxin” into gasoline, “into the daily lives of millions of people. Yet, despite these warnings, millions…were harmed…and this entirely preventable poisoning still occurs today.”

“Virtually all the lead in the environment is there as a result of human activity.” Because we put it there. It used to be locked away, deep underground or under the ocean, but that was before we drove it around the Earth. “In the early 1970s, 200,000 tons of lead was emitted from automobiles in the United States each year, mostly in urban areas.” Had lead not been added to gasoline, the industry would have had to use higher-octane gas, which is less profitable. So, the “oil and lead industries…successfully thwarted government efforts to limit lead in gasoline for 50 years.” But, how were they able to do that? “Early public health warnings were not heeded because the industry assured the scientific community and the public that there was no danger.” I could see how a gullible public might be swayed by slick PR, but how do you manipulate the scientific community? By manipulating the science.

“The lead industry was able to achieve its influence in large part by being the primary supporter of research on health effects of lead,” and it got the best science money could buy. “Long before Big Tobacco, the lead industry understood the inestimable value of purchasing ‘good science.’”

“Consequently, the vast majority of relevant studies of lead in gasoline published [for decades]…were favorable to the lead industries.” What’s more, they “even sent a delegation to try to convince the U.S. EPA administrator that the lead regulation was not necessary because they alleged lead was an essential mineral required for optimum growth and development.”

Of course, the exact opposite is true. Lead is toxic to development. There are, however, nutritional interventions that can help alleviate lead toxicity. For example, there are food components that can help decrease the absorption of lead and help flush it out of your body. I’ve produced a series of three videos on specific dietary interventions, such as particular foods to eat, but—spoiler alert—in general, “food patterns that reduce susceptibility to lead toxicity are consistent with the recommendations for a healthy diet.”

As soon as I learned about the unfolding crisis in Flint, Michigan, I knew I had to take a deep dive into the medical literature to see if there is anything these kids might be able to do diet-wise to reduce their body burden.

Most of the time when I cover a subject on NutritionFacts.org, I’ve addressed it previously, so I just have to research the new studies published in the interim. But I had never really looked deeply into lead poisoning before, so I was faced with more than a century of science to dig through. Yes, I did discover there were foods that could help, but I also learned about cautionary tales like this one about our shameful history with leaded paint. By learning this lesson, hopefully, we can put more critical thought into preventing future disasters that can arise when our society allows profits to be placed over people.


This is part of a series on lead. You can view the rest of the series here:

 You may also be interested in How to Lower Heavy Metal Levels with Diet.

If you enjoyed this article, you may also like:

What relevance does this have for us today? See, for example, my video How Smoking in 1959 Is Like Eating in 2019.

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations: