What are the health consequences of even “low” levels of lead exposure?
“Normal” Blood Lead Levels Can Be Toxic
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
“By the 1950s, lead—a dangerous neurotoxin that was once buried deep in the ground, far [far] away…—had polluted the entire planet,” thanks to leaded gasoline. I mean it’s hard to imagine “a better [way] for maximizing population exposure to a poison than to have it emitted by a ubiquitous mobile source…to line the surfaces of our [neighborhoods] with it.”
“Overall, about 5 million metric tons of lead was deposited….” A single busy street could receive more than a ton a year, and the lead just built up decade after decade, but at least—thanks to regulations starting in the 70s—we stopped spewing so much into the air, and as lead use dropped, so did the levels of lead in our blood, resulting in a 98% reduction in the percentage of young children with elevated blood lead levels. Of course, the term “elevated” is relative.
Prior to 1970, lead toxicity was defined as 60 (μg/dL) or higher, but then, they dropped the definition to 40, then 30, then 25, then 10, as lead levels “previously thought to be safe or inconsequential for children [were] consistently shown to be risk factors” for cognitive and behavioral problems.
Currently, elevated is considered more than 5. But under 5, your lead level is considered non-elevated, normal. But, what does having a “normal” lead level mean?
“[V]irtually all residents of industrialized countries have bone lead stores that are several orders of magnitude greater than those of our pre-industrial ancestors.” If you go to a museum and test the lead levels of ancient skeletons buried a millennium ago, they have a thousand times lower lead level compared to people today, “which indicates the probable existence within most Americans of dysfunctions caused by poisoning from chronic, excessive overexposure[s] to industrial [lead].”
This is a graphical representation, where each dot represents 40 micrograms of lead. The amount of lead in the right figure represents overtly symptomatic lead poisoning, where you might be doubled over in pain, whereas the middle figure is the lead in a typical American citizen, and the left figure is how much they found in pre-industrial bodies. See, what the medical and research community [has] failed to understand is they’d just been looking at these two figures—people with lead poisoning and those of us down at normal levels, so-called “very low levels.” But what these new data, on what’s natural for our species, shows is that typical levels of lead in humans are quite definitely not very low at all, “but instead constitute grossly excessive 1000-fold over-exposure levels.”
The bottom line is that “[n]o 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. But hey, it could have been a lot worse if we hadn’t started restricting leaded gas. Thanks to falling blood lead levels starting in the 70s, preschoolers born in the 90s were like two to five IQ points smarter than kids, like me, born before 1976. So, when we see our kids and grandkids being such whizzes 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 kids are less brain-damaged.
If that seems like a lot for just a few IQ points, what you have to realize is that even a small shift in average IQ could result in a 50% increase in the number of the so-called “mentally retarded,” millions more in need of special education and services.
So, the “[r]emoval of lead from gasoline in the United States may be…one of the great public health achievements of the 20th century, but it almost did not happen.”
“Tremendous pressure by the lead industry…was brought to bear to quiet, even intimidate, researchers and clinicians who [dared report on or identify] lead as a hazard.” Decent “scientists and health officials faced enormous opposition but never lost sight of the mandate to protect public health.”
In this personal perspective, two of the “idealistic” young employees at the newly-formed EPA, who played key roles in the fight, recount how “naive [they were] to the ways of Washington.”
“Our youth was…used against us,” they recall. “[Their] inexperience was cited as a reason for rejecting [their] proposals. In retrospect, however, their “youth and inexperience” may have helped them “to succeed” in taking on a billion-dollar industry. “We were too young to know that regulating lead in gasoline was impossible.”
Please consider volunteering to help out on the site.
- Bridbord K, Hanson D. A personal perspective on the initial federal health-based regulation to remove lead from gasoline. Environ Health Perspect. 2009 Aug;117(8):1195-201.
- Lamphear BP. Childhood lead poisoning prevention: too little, too late. JAMA. 2005 May 11;293(18):2274-6.
- Leech TG, Adams EA, Weathers TD, Staten LK, Filippelli GM. Inequitable Chronic Lead Exposure: A Dual Legacy of Social and Environmental Injustice. Fam Community Health. 2016 Jul-Sep;39(3):151-9.
- Lamphear BP. The Conquest of Lead Poisoning: A Pyrrhic Victory. Environ Health Perspect. 2007 Oct;115(10):A484-5.
- Rosner D, Markowitz, G. The politics of lead toxicology and the devastating consequences for children. Am J Ind Med. 2007 Oct;50(10):740-56.
- Grosse SD, Matte TD, Schwartz J, Jackson RJ. Economic gains resulting from the reduction in children's exposure to lead in the United States. Environ Health Perspect. 2002 Jun;110(6):563-9.
- Stein J, Schettler T, Wallinga D, Valenti M. In harm's way: toxic threats to child development. J Dev Behav Pediatr. 2002 Feb;23(1 Suppl):S13-22.
- Rosner D. A Lead Poisoning Crisis Enters Its Second Century. Health Aff (Millwood). 2016 May 1;35(5):756-9.
- Bellinger DC. Lead Contamination in Flint — An Abject Failure to Protect Public Health. N Engl J Med. 2016 Mar 24;374(12):1101-3.
- Bogden JD, Oleske JM, Louria DB. Lead poisoning--one approach to a problem that won't go away. Environ Health Perspect. 1997 Dec;105(12):1284-7.
- Patterson C, Ericson J, Manea-Krichten M, Shirahata H. Natural skeletal levels of lead in Homo sapiens sapiens uncontaminated by technological lead. Sci Total Environ. 1991 Sep;107:205-36.
- CDC (Centers for Disease Control and Prevention). National Center for Environmental Health. Division of Emergency and Environmental Health Services. Blood Lead Levels in Children What Do Parents Need to Know to Protect Their Children?
Motion graphics by Avocado Video.
Image credit: Cpl. Juan D. Alfonso via US Marine Corps. Image has been modified.
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
“By the 1950s, lead—a dangerous neurotoxin that was once buried deep in the ground, far [far] away…—had polluted the entire planet,” thanks to leaded gasoline. I mean it’s hard to imagine “a better [way] for maximizing population exposure to a poison than to have it emitted by a ubiquitous mobile source…to line the surfaces of our [neighborhoods] with it.”
“Overall, about 5 million metric tons of lead was deposited….” A single busy street could receive more than a ton a year, and the lead just built up decade after decade, but at least—thanks to regulations starting in the 70s—we stopped spewing so much into the air, and as lead use dropped, so did the levels of lead in our blood, resulting in a 98% reduction in the percentage of young children with elevated blood lead levels. Of course, the term “elevated” is relative.
Prior to 1970, lead toxicity was defined as 60 (μg/dL) or higher, but then, they dropped the definition to 40, then 30, then 25, then 10, as lead levels “previously thought to be safe or inconsequential for children [were] consistently shown to be risk factors” for cognitive and behavioral problems.
Currently, elevated is considered more than 5. But under 5, your lead level is considered non-elevated, normal. But, what does having a “normal” lead level mean?
“[V]irtually all residents of industrialized countries have bone lead stores that are several orders of magnitude greater than those of our pre-industrial ancestors.” If you go to a museum and test the lead levels of ancient skeletons buried a millennium ago, they have a thousand times lower lead level compared to people today, “which indicates the probable existence within most Americans of dysfunctions caused by poisoning from chronic, excessive overexposure[s] to industrial [lead].”
This is a graphical representation, where each dot represents 40 micrograms of lead. The amount of lead in the right figure represents overtly symptomatic lead poisoning, where you might be doubled over in pain, whereas the middle figure is the lead in a typical American citizen, and the left figure is how much they found in pre-industrial bodies. See, what the medical and research community [has] failed to understand is they’d just been looking at these two figures—people with lead poisoning and those of us down at normal levels, so-called “very low levels.” But what these new data, on what’s natural for our species, shows is that typical levels of lead in humans are quite definitely not very low at all, “but instead constitute grossly excessive 1000-fold over-exposure levels.”
The bottom line is that “[n]o 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. But hey, it could have been a lot worse if we hadn’t started restricting leaded gas. Thanks to falling blood lead levels starting in the 70s, preschoolers born in the 90s were like two to five IQ points smarter than kids, like me, born before 1976. So, when we see our kids and grandkids being such whizzes 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 kids are less brain-damaged.
If that seems like a lot for just a few IQ points, what you have to realize is that even a small shift in average IQ could result in a 50% increase in the number of the so-called “mentally retarded,” millions more in need of special education and services.
So, the “[r]emoval of lead from gasoline in the United States may be…one of the great public health achievements of the 20th century, but it almost did not happen.”
“Tremendous pressure by the lead industry…was brought to bear to quiet, even intimidate, researchers and clinicians who [dared report on or identify] lead as a hazard.” Decent “scientists and health officials faced enormous opposition but never lost sight of the mandate to protect public health.”
In this personal perspective, two of the “idealistic” young employees at the newly-formed EPA, who played key roles in the fight, recount how “naive [they were] to the ways of Washington.”
“Our youth was…used against us,” they recall. “[Their] inexperience was cited as a reason for rejecting [their] proposals. In retrospect, however, their “youth and inexperience” may have helped them “to succeed” in taking on a billion-dollar industry. “We were too young to know that regulating lead in gasoline was impossible.”
Please consider volunteering to help out on the site.
- Bridbord K, Hanson D. A personal perspective on the initial federal health-based regulation to remove lead from gasoline. Environ Health Perspect. 2009 Aug;117(8):1195-201.
- Lamphear BP. Childhood lead poisoning prevention: too little, too late. JAMA. 2005 May 11;293(18):2274-6.
- Leech TG, Adams EA, Weathers TD, Staten LK, Filippelli GM. Inequitable Chronic Lead Exposure: A Dual Legacy of Social and Environmental Injustice. Fam Community Health. 2016 Jul-Sep;39(3):151-9.
- Lamphear BP. The Conquest of Lead Poisoning: A Pyrrhic Victory. Environ Health Perspect. 2007 Oct;115(10):A484-5.
- Rosner D, Markowitz, G. The politics of lead toxicology and the devastating consequences for children. Am J Ind Med. 2007 Oct;50(10):740-56.
- Grosse SD, Matte TD, Schwartz J, Jackson RJ. Economic gains resulting from the reduction in children's exposure to lead in the United States. Environ Health Perspect. 2002 Jun;110(6):563-9.
- Stein J, Schettler T, Wallinga D, Valenti M. In harm's way: toxic threats to child development. J Dev Behav Pediatr. 2002 Feb;23(1 Suppl):S13-22.
- Rosner D. A Lead Poisoning Crisis Enters Its Second Century. Health Aff (Millwood). 2016 May 1;35(5):756-9.
- Bellinger DC. Lead Contamination in Flint — An Abject Failure to Protect Public Health. N Engl J Med. 2016 Mar 24;374(12):1101-3.
- Bogden JD, Oleske JM, Louria DB. Lead poisoning--one approach to a problem that won't go away. Environ Health Perspect. 1997 Dec;105(12):1284-7.
- Patterson C, Ericson J, Manea-Krichten M, Shirahata H. Natural skeletal levels of lead in Homo sapiens sapiens uncontaminated by technological lead. Sci Total Environ. 1991 Sep;107:205-36.
- CDC (Centers for Disease Control and Prevention). National Center for Environmental Health. Division of Emergency and Environmental Health Services. Blood Lead Levels in Children What Do Parents Need to Know to Protect Their Children?
Motion graphics by Avocado Video.
Image credit: Cpl. Juan D. Alfonso via US Marine Corps. Image has been modified.
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“Normal” Blood Lead Levels Can Be Toxic
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Content URLDoctor's Note
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:
- How to Lower Lead Levels with Diet: Thiamine, Fiber, Iron, Fat, Fasting?
- How to Lower Lead Levels with Diet: Breakfast, Whole Grains, Milk, Tofu?
- Best Foods for Lead Poisoning: Chlorella, Cilantro, Tomatoes, Moringa?
- Best Food for Lead Poisoning: Garlic
- Can Vitamin C Help with Lead Poisoning?
- Yellow Bell Peppers for Male Infertility and Lead Poisoning?
If you missed the first three videos in this series, check out:
- How the Lead Paint Industry Got Away with It
- Lead in Drinking Water
- How the Leaded Gas Industry Got Away with It
For the effects of mercury, another heavy metal, see:
- How Long to Detox from Fish Before Pregnancy?
- Mercury vs. Omega-3s for Brain Development
- Is Fish “Brain Food” for Older Adults?
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