Targeted
Lead Detox with Thiamine, Zinc, and Selenomethionine
Dennis
N. Crouse 11/18/19
“Lead
has inflicted more deficits to human intelligence than any other pollutant.” P. Grandjean1
Lead is an element found in
the earth’s crust. Because of its ductility and low cost it has been mined and
processed into a variety of useful chemicals and products. More lead than ever
before makes its way into our bodies primarily from our drinking water and the
air we breathe. Since the amount of lead ingested and inhaled has increased, the
amount of lead in our bones has also increased more than 10 fold1. Major
sources of lead include:
·
Lead in drinking water – A
2016 American Water Works Association Study estimated that more than 6.1
million homes in the U.S. get drinking water through lead pipes called “service
lines”2. Because of lead corrosion in these pipes, levels of lead
exceeding the EPA’s action level (15mcg/L) persist in some cities. Recent
examples include Flint, MI where 9,000 children were exposed to lead levels as
high as 1500mcg/L and Newark, NJ where 10% of drinking water samples exceeded
66.9mcg/L.
·
Tetraethyl lead (TEL) as a gasoline additive – TEL was phased out as a road vehicle fuel additive in the U.S.
by early 2000’s. However, TEL is still used in aviation gasoline (a.k.a. avgas)
for planes with internal combustion engines and in gasoline for road vehicles of
some developing countries3.
·
Lead from coal-fired power plants - In
2008 103 facilities in the U.S. were identified as emitting more than 1,000 pounds
of lead per year into the atmosphere4.
·
Lead from paint - Lead paint is a major
source of lead exposure in children5. It is estimated there were 38
million housing units in the U.S. that had lead paint in 20006. Even a small paint chip can contain 10 to100
milligrams of lead7.
On
October 10, 2019 the U.S. Environmental Protection Agency (EPA) announced a
proposal to create a trigger level
of 10mcg/L of lead in drinking water tested at water taps inside homes8.
This proposal does not change the EPA’s current action level of 15mcg/L of lead in drinking water. The EPA’s trigger
and action levels for lead in drinking water are not a threshold for public
health so a lead reading below that level doesn’t mean the drinking water is
safe9.
On November 12, 2008 the U.S.
EPA substantially strengthened the national ambient air quality standard for
lead (73 FR 66964). The EPA revised the
level of the primary (health-based) standard from 1.5mcg of lead per cubic
meter to 0.15mcg of lead per cubic meter of air4.
Safe levels for lead exposure in air and drinking water have not
been defined as health risks associated
with lead have been shown at very low doses.
For example, over 99% of the lead present in blood accumulates in
erythrocytes and of this over 80% is bound to an enzyme ALAD
(delta-aminolevulinic acid dehydrogenase)10. A blood level of only
15mcg/L results in 50% inhibition of (ALAD) resulting the accumulation of
aminolevulinc acid (ALA) that has neurotoxic activity contributing to
lead-induced toxicity of the brain11,12.
Individuals with certain
genetic characteristics may not be protected by current regulatory standards
for lead. For example, the ALAD gene contains two co-dominate alleles that
depending upon which allele is expressed by an individual person results in
higher or lower amount of neurotoxic ALA in response to lead10-12.
In addition, people with a recessive genetic disorder called ALAD porphyria
have an almost complete lack of ALAD and for this reason have increased
sensitivity to lead exposure13.
Lead Exposure Causes IQ Loss in Children
Lead in the bodies of children
causes developmental delays in their brains resulting in lower IQ1.
Because of this children are more vulnerable to lead toxicity than are adults.
In 1986 the World Health Organization (WHO) set a special lead exposure limit for children at 50% of the adult
exposure limit. In 2008 the World governmental Committee on Toxicology (COT)
estimated that infants and young children exposed to WHO’s special lead
exposure limit would have approximately a 36 mcg/L increase in blood lead
level. This increase in blood lead level would in turn cause a 0.36 – 1.8 point
decline in children’s IQ1.
In 1991 the CDC lowered the
definition of lead toxicity from blood lead levels of 600mcg/L to 100mcg/L14. Currently the CDC recommends public health
intervention when a child’s blood lead level is more than 50mcg/L15.
But now there are three studies that show that lead can cause IQ deficits in
children at levels well below 100mcg/L16-18. There is a greater
change in IQ with respect to lead concentrations from 10 to 100mcg/L than the
change in IQ from 100 to 200mcg/L of lead in blood17,18. This surprising result indicates that most of
the brain damage occurs at the lowest doses of lead14.
This loss of IQ due to lead
is an example of what is called “chemical brain drain”. There
is no safe level of lead that avoids “chemical brain drain” in infants and
children’s brains. Targeted detox aimed at removing lead from the body is
the only way to prevent “chemical brain drain” due to lead.
In addition to IQ loss, other
symptoms of lead at blood lead levels less than 100mcg/L in children include19:
·
Altered mood and behaviors
that may contribute to learning deficits, including attention deficits,
hyperactivity, autistic behaviors, conduct disorders, and delinquency.
·
Altered neuromotor and
neurosensory function, including gross and fine motor skills, visual-motor
integration, and hearing threshold.
Lead Exposure Causes Mild Cognitive Impairment (MCI) in Adults
Impairments in cognitive
function, typically memory loss at a greater rate than seen in normal aging, is
called mild cognitive impairment (MCI). MCI is a transitional state between the
cognition seen in normal aging and dementia20. If the primary
symptom is memory impairment, this state is called amnestic MCI. Amnestic MCI may
not only be the first observable stage in Alzheimer’s disease but MCI is also a
deficit in its own right that can be prevented and treated by modifying risk factors21.
Chronic accumulation of lead in the body is an example of a risk factor for MCI
that can be modified by targeted lead detox.
The U.S. National Institute
for Occupational Safety and Health (NIOSH) in 2015 indicated 50mcg/L as a
reference blood lead level for adults.
In spite of this the U.S. Occupational Safety and Health Administration
(OSHA) recommends removing workers from lead exposure if their blood lead level
is above 600mcg/L, and readmit them to work when it is below 400mcg/L. The
American Conference of Governmental Industrial Hygienists (ACGIH) has set a
biological exposure index of 300mcg/L for workers22.
In an ideal world in order to
test for lead causing MCI in adults would require two groups of people: one with
and one without lead in their blood. However, in our lead-polluted world it is
impossible to find an adult population that does not have some lead in their
blood. In 2016 40 non-lead exposed
adults as a control group were age-matched to 45 lead-exposed workers and both
their blood lead levels and cognition were tested. The non-lead exposed group had a mean blood
lead level of 154mcg/L and the lead exposed group has a mean blood lead level
of 564mcg/L22.
Even with the control group
not being lead-free, neuropsychological testing revealed a significant difference
between the exposed and control groups in the areas of executive functions,
short term memory, and psycho-emotional variables: tension, anxiety, and
depression22. The conclusion is that greater lead exposure in adults
does cause greater MCI.
Since there is no such thing
as a “non-exposed” adult, even non-occupationally exposed adults have some MCI
due to lead accumulation. This was tested in a cohort totaling 1089
community-dwelling elderly retired men with a mean age of 68.7 + 7.4
years. Blood and bone lead concentrations were measured along with cognitive
assessment during the period 1991 to 1999. Performance on all cognitive tests
worsened over time as function of increasing bone-lead level. The largest effects
due to lead were observed to be on performance and reaction time scores in the
visuospatial/visuomotor domain. It was concluded that non-occupational lead
accumulation in adults does result in MCI23.
In addition to MCI, other
symptoms of lead at blood lead levels less than 100mcg/L in adults include19:
·
Altered mood and behaviors
including risk of various psychiatric symptoms including anxiety, depression,
and schizophrenia.
·
Altered neuromotor and
neurosensory function including decreased reaction time and walking speed,
tremor, and increased risk of amyotrophic lateral sclerosis (ALS).
Thiamine (Vitamin B1) for Targeted Lead Detox
Thiamine (a.k.a. vitamin B1) facilitates
the elimination of lead in the bile and urine and lowers both tissue and blood
lead levels. When the diet of sheep was
supplemented with thiamine (75mg/kg of body weight) there was a 72% increase in
biliary and urinary excretion of lead24. Calves treated for 20 days with both lead
(5mg/day/kg) and thiamine (100mg/day) have 2 to 10 times less lead in their
tissues as compared with calves treated with only lead25. Just two
doses of thiamine (25mg/dose/kg of body weight) in the same day lowered the
blood lead level 53% from 518mcg/L to 243 mcg/L in sheep treated with lead acetate
(25mg/kg) for five days. In addition there was a significant reduction in serum
zinc concentration in thiamine-treated animals26.
In human studies with 13 men between
22-44 years of age who were being chronically and occupationally exposed to lead
fumes for 10-15 years prior to and during the study period. Their blood lead level at the start of the
study averaged 441mcg/L and ranged from 319 to 501mcg/L. They took orally twice
a day 50mg tablets of thiamine during the first 3 months and then took 100mg tablets
twice a day for 30 days. Blood tests for lead revealed 14% lower blood lead
levels after 4 months of treatment with 50-100mg of thiamine twice a day27.
This is impressive in light of their past and continued occupational exposure
to lead fumes.
Note that retention of oral
thiamine in the human body is not more than 15mg even with mega doses of
thiamine from 50 to 200mg27. After oral administration to humans
thiamine’s elimination half-life is 154 minutes with only 2.5% recovered in the
urine28.
Spectroscopic studies have
revealed that lead interacts with the aminopyrimidine ring of thiamine leading
to lead solubilization at physiological pH29. Lead also interacts
with the sulfur atom in the thiazolium ring of thiamine. When this sulfur is
blocked by acylation, such as in Benfotiamine, the modified thiamine can’t provide
protection from lead30. Thiamine reduces lead levels in the blood,
kidney, and bone during both simultaneous and post-exposure lead treatment29.
The likely mechanism for targeted lead detox by thiamine involves facilitating both
biliary and urinary excretion of lead when complexed with
thiamine29,31.
Thiamine (Vitamin B1) Supplements
Thiamine (a.k.a. vitamin B1,
B-1) can be taken as a supplement in pure form or in a B vitamin complex. For instance a B50 complex tablet contains
50mg of thiamine and a B100 complex tablet contains 100mg of thiamine. Time-release
B50 or B100 complexes are available from CVS and Puritan Pride. Non-time
released tablets of just B-1 are available from Now Foods Company as 100mg
tablets of B-1 (thiamine hydrochloride HCl) and Seeking Health as 50mg vegetarian
capsules of B-1 (thiamine hydrochloride HCl).
Zinc for Targeted Lead Detox
In rats fed a dietary
supplement of lead acetate (50mg/kg of body weight) for 3 months there was
higher than normal levels of lead in bone, kidney, prostate, testis, liver,
epididymis, spleen, seminal vesicles, and blood. If these rats were
co-administered a dietary supplement of zinc sulfate (1mg/kg of body weight)
there was as much as a 30% decrease in the amount of lead accumulated in these
organs32.
Zinc Supplements
The most bioavailable source
of zinc is an amino acid or acid chelate of zinc such as zinc bisglycinate of
zinc gluconate. Vendors of zinc supplements include Nature’s Way 30mg capsules
of zinc bisglycinate and Carlson Labs 15mg tablets of zinc gluconate.
Thiamine and Zinc for Targeted Lead Detox
In order to decrease the
accumulation of lead in rats ingesting lead, it was found that a combination of
thiamine and zinc as a dietary supplement is more effective than either
thiamine or zinc alone33. Simultaneous dietary supplementation
thiamine and zinc to rats that had been exposed to lead, decreased lead
accumulation in the blood, liver, and kidney to a greater extent than either thiamine
or zinc supplementation. Rats that were exposed to lead after having been given
previously simultaneous thiamine and zinc supplementation had even a larger
decrease of lead in the blood, liver, and kidneys. Therefore prevention is more
effective than post-lead supplementation for decreasing lead accumulation33.
Selenomethionine for Targeted Lead Detox
Selenium can’t be solely recommended
for lead detox. This is because, even though selenium has been shown to
detoxify lead, it has not been shown to facilitate the excretion of lead.
In children, as whole blood and
plasma selenium levels increase, serum lead levels decrease34. In adults exposed to lead the levels of lead
in the blood are 6% lower in those with higher blood selenium levels as
compared with those with lower blood selenium levels35. Therefore in
both children and adults higher blood plasma levels of selenium result in lower
blood lead levels and less loss of IQ and cognition.
In the erythrocyte as concentration
of lead increases so does the concentration selenium36. This is
likely due to lead and selenium reacting together in the erythrocytes to form non-toxic
lead selenide complex37. Therefore, lead toxicity increases the
selenium and lead concentration in the erythrocytes while depleting selenium
from the plasma. A selenium supplement would increase the selenium
concentration in the plasma and increase the amount of lead detoxified in the erythrocytes,
while decreasing lead in the blood plasma and decreasing IQ and cognition loss.
Selenomethionine
Supplements
Supplements for human use are not regulated by the U.S. FDA.
Because of this lack of regulation some selenomethionine supplements contain no
selenomethionine or less than the amount stated on the label38-40.
Therefore products with third party certification are recommended. Certifying agencies include: Consumerlab.com,
NSF International, U.S. Pharmacopeia (USP), and UL. There are commercial test laboratories that
also perform third party testing for purity and percent of selenium as
selenomethionine.
The European Food Safety Authority (EFSA) has published a
scientific opinion on acceptable selenium-enriched yeasts produced as
selenomethionine supplements for human use. The source of selenium must be
sodium selenite and the resulting product should contain 60 to 85%
selenomethionine with less the 10% additional organic selenium and less than 1%
inorganic selenium, such as residual sodium selenite. The dried product should
contain no more than 2.5mg of selenium per gram41.
I am
aware of only one selenium-enriched yeast supplement that has been tested by
third parties. This is Bio-SelenoPrecise® tablets manufactured
in Denmark by Pharma Nord under patent no. 1 478 732 B1. This type of
L-selenomethionine supplement is 88.7% absorbed in Danish men with high
habitual selenium intake42, however only about 34% may actually be
free selenomethionine after gastrointestinal digestion43. Pharma Nord packages tablets of
Bio-SelenoPrecise® as 50, 100, and 200mcg of selenomethionine that can be cut
in half with a pill-cutter.
Pharma Nord selenomethionine has been checked by two laboratories
and it has 69-83% L-selenomethionine, 5% or less additional organic selenium,
including selenocysteine, less than 1% inorganic selenium, and less than 2.2mg
per gram of selenium. These results are summarized as product 3a, 3b, and 4 in
EFSA’s Table 1 and they meet EFSA specifications for selenium-enriched yeast41.
Some selenomethionine supplements are made with higher purity than
supplements made from selenium-enhanced yeast. However, it has been reported
that plasma selenium is significantly higher when taking Pharma Nord
Bio-SelenoPrecise® than seen in a comparable population of human subjects
taking the same dose of higher purity selenomethionine44.
Manufactures
of high purity yeast-free selenomethionine who have their product third party
certified and/or tested include Sabinsa Corporation.
Their Selenium SeLECT® product contains a minimum of 1.25% of
L-selenomethionine, measured by HPLC, and 98.75% of dicalcium phosphate,
measured by titration. Therefore it is
100% selenium as selenomethionine. Sabinsa Corp. has both UPC and NSF
International product certification. Selenium SeLECT® is packaged and sold
by Swanson (100mcg capsules) and Vitacost (200mcg capsules). Make sure the Supplement Facts on the
bottles state: “Selenium from (as) Selenium SeLECT® L-selenomethionine”.
The Food and Nutrition Board (FNB) of the U.S. Institute of
Medicine has set the tolerable upper intake levels (UL) for selenium based upon
age, including both selenium obtained from food and selenium obtained from
supplements, as indicated in Table 145.
Recommendations
for Targeted Lead Detox
Since we may be chronically exposed to lead from the
air, drinking water, and lead paint, it is recommended to make a life-style
choice of taking the following three supplements for the rest of your life:
·
Thiamine (a.k.a. vitamin B1,
thiamin) - 50mg for children and 50-100mg
for adults twice a day (morning and evening) or a time-released B50 or B100
complex once a day.
·
Zinc - 15mg for children and
30mg for adults per day (do not exceed 40mg per day)
·
Selenomethionine - The
following amounts are recommended for targeted detox of not only lead but also
mercury and arsenic:
·
Children 0 to 3 years of age: 25mcg/day
·
Children 4 to 8 years of age: 50mcg/day
·
Children 9 to 13 years of age: 100mcg/day
·
Adolescents 14 to 18 years of age and adults:
100-200mcg/day
Note that too much selenium will give you garlic-breath. So cut
back on the amount of selenium per day if you are accused of having
garlic-breath without eating garlic.
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