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:

 

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:

What Exercise Authorities Don’t Tell You About Optimal Duration

Physical fitness authorities seem to have fallen into the same trap as the nutrition authorities, recommending what they think may be achievable, rather than simply informing us of what the science says and letting us make up our own minds.

Researchers who accept grants from The Coca-Cola Company may call physical inactivity “the biggest public health problem of the 21st century,” but, in actually, physical inactivity ranks down at number five in terms of risk factors for death in the United States and even lower in terms of risk factors for disability, as you can see at 0:17 in my video How Much Should You Exercise? What’s more, inactivity barely makes the top ten globally. As we’ve learned, diet is our greatest killer by far, followed by smoking.

Of course, that doesn’t mean you can just sit on the couch all day. Exercise can help with mental health, cognitive health, sleep quality, cancer prevention, immune function, high blood pressure, and life span extension, topics I cover in some of my other videos. If the U.S. population collectively exercised enough to shave just 1 percent off the national body mass index, 2 million cases of diabetes, one and a half million cases of heart disease and stroke, and 100,000 cases of cancer might be prevented.

Ideally, how much should we exercise? The latest official “Physical Activity Guidelines for Americans” recommends adults get at least 150 minutes a week of moderate aerobic exercise, which comes out to be a little more than 20 minutes a day. That is actually down from previous recommendations from the Surgeon General, as well as from the Centers for Disease Control and Prevention (CDC) and the American College of Sports Medicine, which jointly recommend at least 30 minutes each day. The exercise authorities seem to have fallen into the same trap as the nutrition authorities, recommending what they think may be achievable, rather than simply informing us what the science says and letting us make up our own minds. They already emphasize that “some” physical activity “is better than none,” so why not stop patronizing the public and just tell everyone the truth?

As you can see at 2:16 in my video, walking 150 minutes a week is better than walking 60 minutes a week, and following the current recommendations for 150 minutes appears to reduce your overall mortality rate by 7 percent compared with being sedentary. Walking for just 60 minutes a week only drops your mortality rate about 3 percent, but walking 300 minutes weekly lowers overall mortality by 14 percent. So, walking twice as long—40 minutes a day compared with the recommended 20 daily minutes—yields twice the benefit. And, an hour-long walk each day may reduce mortality by 24 percent. I use walking as an example because it’s an exercise nearly everyone can do, but the same applies to other moderate-intensity activities, such as gardening or cycling.

A meta-analysis of physical activity dose and longevity found that the equivalent of about an hour a day of brisk walking at four miles per hour was good, but 90 minutes was even better. What about more than 90 minutes? Unfortunately, so few people exercise that much every day that there weren’t enough studies to compile a higher category. If we know 90 minutes of exercise a day is better than 60 minutes, which is better than 30 minutes, why is the recommendation only 20 minutes? I understand that only about half of Americans even make the recommended 20 daily minutes, so the authorities are just hoping to nudge people in the right direction. It’s like the Dietary Guidelines for Americans advising us to “eat less…candy.” If only they’d just give it to us straight. That’s what I try to do with NutritionFacts.org.

Most of the content in my book How Not to Die came from my video research, but this particular video actually sprung from the book. I wanted to include exercise in my Daily Dozen list, but needed to do this research to see what was the best “serving size.”

I wish someone would start some kind of FitnessFacts.org website to review the exercise literature. I’ve got my brain full with the nutrition stuff—though there’s so much good information I don’t have time to review that there could be ten more sites just covering nutritional science!


For more on all that exercise can do for our bodies and minds, see

Some tips for maximizing the benefits:

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: