metals are a well-known cause of environmental
pollution and of serious
hazard to human health. The effects of their actions are
not immediate, but show up after many years or decades. Due to their wide usage
in many industrial branches they are present everywhere in the air, water
and soil. Food contaminant by heavy elements is hard to avoid and it is a
result of environmental contamination by dusts, industrial gases, sewage,
waste and coal burning processes. The content of heavy metals in the
environment is quite diverse and their harmful action depends on the type
of element, the chemical form of their occurrence and the state of
organism's nutrition. One of the very toxic and also very frequently used
heavy metal is mercury. Exposure to mercury can cause
neurological, motor and behavioral dysfunctions.
Fish consumption is a main source of mercury intake by Americans. Mercury finds itself into waterways, mostly through the burning of fossil fuels like coal, where bacteria convert it to toxic methyl mercury. Small fish eat or absorb methyl mercury, which becomes more concentrated as it moves up the food chain into large predatory fish. Mercury binds to the meat and cannot be removed from fish by cooking or removing the fat.
Environ Sci Technol. 2012. Organic selenium supplementation increases mercury excretion and decreases oxidative damage in long-term mercury-exposed residents from Wanshan, China. Due to a long history of extensive mercury mining and smelting activities, local residents in Wanshan, China, are suffering from elevated mercury exposure. The objective of the present study was to study the effects of oral supplementation with selenium-enriched yeast in these long-term mercury-exposed populations. One hundred and three volunteers from Wanshan area were recruited and 53 of them were supplemented with 100 μg of organic selenium daily as selenium-enriched yeast while 50 of them were supplemented with the nonselenium-enriched yeast for 3 months. The effects of selenium supplementation on urinary mercury, selenium, and oxidative stress-related biomarkers including malondialdehyde and 8-hydroxy-2-deoxyguanosine were assessed. This 3-month selenium supplementation trial indicated that organic selenium mineral supplementation could increase mercury excretion and decrease urinary malondialdehyde and 8-hydroxy-2-deoxyguanosine levels in local residents.
Sushi, how safe is it?
Eating sushi may expose us to a higher level of mercury than we may realize. In 2006, Eli Saddler of gotmercury dot org, a campaign of California-based Sea Turtle Restoration Project, went to six top sushi restaurants in Los Angeles to test the mercury levels in the fish they serve. The tuna samples from the six popular sushi restaurants in Los Angeles were taken to a Southern California lab for testing. The samples had an average mercury level of 0.721 parts per million, about 88 percent higher than the Food and Drug Administration maximum level of 0.383 ppm for fresh and frozen tuna. Big-eyed tuna and blue and yellow-finned tuna are the most popular varieties used in sushi restaurants. Older and bigger fish are considered best suited for sushi but Saddler said it was not widely known that fish with longer lives carry more mercury than others. Studies show seafood like shrimp and salmon with short life spans pose almost no risk of carrying mercury. Long-living, large predatory fish like tuna are the most likely to have mercury contamination.
Dr. Sahelian comments: Unless you are eating a large amount of sushi on a regular basis, I don't think you need to be concerned. Just eat less tuna sushi and have a variety of different fish.
Tuna and fish content, pregnancy
Despite concerns over mercury exposure, pregnant women who eat lots of fish may not harm their unborn children. The omega 3 fatty acids found in fish oil may protect the brain from the potential toxic effects of mercury; Jan. 21, 2015, American Journal of Clinical Nutrition.
Levels of mercury in Pacific Ocean fish are likely to rise over coming decades. Up to 80 percent of the toxic form of mercury (methylmercury) found in deep-feeding North Pacific fish is produced in the ocean's depths, probably by bacteria that cling to sinking bits of organic matter. This metal found in fish near Hawaii likely traveled through the air for thousands of miles before being deposited in the ocean by rainfall. North Pacific fisheries are downwind from rapidly industrializing nations such as China and India. These nations increasingly rely on coal-burning power plants, which are a major source of this metal's pollution.
In 2006, San Francisco Superior Court Judge Robert Dondero ruled that
tuna companies do not have to put labels on their cans warning the fish contains
mercury. The lawsuit was brought by California's attorney general Bill Lockyer,
who in 2004 sought to ban the sale of canned tuna without mercury warnings.
Lockyer sued Del Monte Foods, maker of StarKist tuna; Bumble Bee Seafoods, a
unit of Connors Brothers Income Fund of Canada, maker of Bumble Bee tuna; and
Tri-Union Seafoods, maker of Chicken of the Sea tuna. The complaint alleged the
firms violated state Proposition 65, an initiative approved by voters in 1986 to
require firms to issue warnings before exposing people to "known carcinogens or
reproductive toxins." Although most fish contain trace amounts of mercury,
some species, such as tuna and swordfish, can have higher levels.
Tilapia and trout have low mercury levels, as do shrimp, crab and scallops. Both farmed and wild salmon are low in mercury and high in essential omega-3 fats. As well, fish oil supplements are a safe way to get omega-3 fatty acids because they are generally made from smaller fish like sardines and anchovies.
Asian J Androl. 2013. Environmental mercury exposure, semen quality and reproductive hormones in Greenlandic Inuit and European men: a cross-sectional study. No significant association was found between blood concentrations of mercury and any of the other measured semen characteristics (semen volume, total sperm count, sperm concentration, morphology and motility) and reproductive hormones (free androgen index (FAI), follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone and LH ◊ testosterone) in any region. In conclusion, the findings do not provide evidence that environmental mercury exposure in Greenlandic and European men with median whole blood concentration up to 10 ng ml(-1) has adverse effects on biomarkers of male reproductive health.
Q. Should women avoid eating canned tuna? According to
Consumer Reports, this is what they say, "Pregnant women should not eat canned
tuna because it may contain harmful levels of mercury."
A. Government tests found instances where canned light tuna had as much mercury, a potentially harmful heavy metal, as white tuna, also known as albacore. High levels of mercury in the bloodstream may harm developing nervous systems, according to the Food and Drug Administration. Fish and shellfish are the main sources of mercury exposure for humans. However, I don't think one needs to completely avoid canned tuna. One or two cans a month should be perfectly okay.
Mercury Dental Filings and toxicity, results have not
Neuro Endocrinol Lett. 2014. Evidence supporting a link between dental amalgams and chronic illness, fatigue, depression, anxiety, and suicide. The purpose of this review is to examine the evidence for a relationship between mercury (Hg) exposure from dental amalgams and certain idiopathic chronic illnesses--chronic fatigue syndrome (CFS), fibromyalgia (FM), depression, anxiety, and suicide. Dental amalgam is a commonly used dental restorative material that contains approximately 50% elemental mercury (Hg0) by weight and releases Hg0 vapor. Studies have shown that chronic Hg exposure from various sources including dental amalgams is associated with numerous health complaints, including fatigue, anxiety, and depression--and these are among the main symptoms that are associated with CFS and FM. In addition, several studies have shown that the removal of amalgams is associated with improvement in these symptoms. Although the issue of amalgam safety is still under debate, the preponderance of evidence suggests that Hg exposure from dental amalgams may cause or contribute to many chronic conditions. Thus, consideration of Hg toxicity may be central to the effective clinical investigation of many chronic illnesses, particularly those involving fatigue and depression.
2006 - Two long-awaited, government-funded studies found no evidence that dental fillings containing mercury can cause IQ-lowering brain damage or other neurological problems in children. Children with such fillings were no more likely than other youngsters to suffer such problems. The studies are unlikely to end the fierce debate over the long-term effects of what are known as amalgam fillings. Amalgam fillings, also called silver fillings, are made of mercury and other metals and have been used by dentists for more than a century. But their use has dropped in recent years as more and more doctors switch to resin composite fillings, which are considered more appealing because they are white.
2006 - Government health advisers rejected a federal report that concluded the mercury-laden amalgam that dentists use to fill cavities was safe, saying further study was needed. A panel of Food and Drug Administration advisers did not declare silver fillings were unsafe. But in a 13-7 vote Thursday, the advisers said a federal report didnít objectively and clearly present the current state of knowledge about the fillings. In a second 13-7 vote, the panelists said the reportís conclusions about safety werenít reasonable.
2006 - Food and Drug Administration reviewed 34 studies and found "no significant new information" that would change its determination that mercury -based fillings don't harm patients, except in rare cases where they have allergic reactions. Consumer groups opposed to the use of mercury for dental filings disputed the FDA's conclusions. The groups plan to petition the agency for an immediate ban on use of mercury dental filings in pregnant women. Amalgam fillings, also called silver fillings, by weight are about 50 percent mercury, joined with silver, copper and tin. Dentists have used amalgam to fill cavities since the 1800s. Today, tens of millions of Americans receive mercury fillings each year. Amalgam use has begun to decline, however, with many doctors switching to resin composite fillings, considered more appealing since they blend better with the natural coloring of teeth. With amalgam fillings, mercury vapor is released through tooth-brushing and chewing. In general, significant levels of mercury exposure can permanently damage the brain and kidneys. Fetuses and children are especially sensitive to its harmful effects. Scientists have found that mercury levels in the blood, urine and body tissues rise the more mercury fillings a person has. "If substantial scientific evidence showed that dental amalgam posed a threat to the health of dental patients, we would advise dentists to stop using it. But the best and latest available scientific evidence indicates that dental amalgam is safe," said Dr. Ronald Zentz, senior director of the American Dental Association's council on scientific affairs. Rep. Diane Watson, D-California., who has introduced legislation that would effectively ban the use of mercury in dental fillings by 2008. Watson will press the FDA for a ban and call on the agency to study the environmental impact of dental mercury. Also on the legislative front, Sen. Mike Enzi, R-Wyoming., and other Senate colleagues have asked President Bush's nominee to head the FDA about the safety of mercury fillings.
2008 - Mercury fillings may cause health problems in pregnant women, children and fetuses, the Food and Drug Administration has admitted. Millions of Americans have the fillings, or amalgams, to patch cavities in their teeth. "Dental amalgams contain mercury, which may have neurotoxic effects on the nervous systems of developing children and fetuses," the FDA said on its Web site. "Pregnant women and persons who may have a health condition that makes them more sensitive to mercury exposure, including individuals with existing high levels of mercury, should not avoid seeking dental care, but should discuss options with their health practitioner," the agency said. Mercury has been linked to brain and kidney damage at certain levels. Amalgams contain half mercury and half a combination of other metals. Only 30 percent of fillings given to patients were mercury-filled ones as of 2003, according to the American Dental Association (ADA). Other options include glass cement and porcelain as well as other metals such as gold, but they cost more and are less durable.
Q. Could you shed some light on mercury toxicity? I had
an amalgam removed a few months ago and the oxygen mask was not working, I think
I inhaled, what are the symptoms of inhaled mercury?
A. I have not studied the toxicity of inhaled mercury.
Do you have an opinion about the possible dangers of mercury amalgam dental fillings, or the best way to remove / replace them? I am 51 and have 19 amalgam surfaces in my teeth, and my late father had Parkinsonism. I'm considering having my amalgams removed using an IAOMT protocol designed to minimize patient exposure to mercury during the removal process. I would likely replace these fillings with either composite resin or gold inlays. I'm also considering using some kind of chelator--perhaps DMSA--during or after the removal.
Is excessive mercury ingestion a cause of autism? I found a study that evaluated the role of mercury in autism.
Low-level chronic mercury exposure in children and
Pediatr Int. 2007. Department of Paediatrics, Kwong Wah Hospital, Kowloon, Hong Kong.
Mercury is a well-known neurotoxin. There are three kinds of mercury exposure: elemental mercury poisoning, inorganic mercury poisoning and organomercury poisoning. Organomercury is the most toxic. Twenty-four hour urine for mercury and blood mercury are the gold standards for diagnosis of mercury poisoning, including low-level chronic mercury exposure. Other tests for mercury level are discussed. The purpose of the present paper was to review recent data on the nature, pathophysiology, pharmacokinetics, diagnostic methods, treatment and the linkage to neurodevelopmental disabilities of mercury exposure in children. A literature search was undertaken of MEDLINE (1980-2003), and American Academy of Pediatrics, American Medical Association, American Dental Association, World Health Organization and Center for Disease Control websites. The search string 'mercury' was used in MEDLINE and articles were selected as appropriate by two independent reviewers. All relevant information was reviewed and data were extracted by two independent reviewers. Based on the meta-analysis of the accuracy of hair mercury, hair mercury levels correlated with mercury level in blood, with 24 h urine and with cord blood. However, the correlation for hair mercury level with 24 h urine level and blood level was not high enough to replace them in clinical decision-making of individual patient. Epidemiological evidence has shown that low-level mercury poisoning is not a cause of autism. The risk of neurodevelopmental disabilities from low-level exposure to methylmercury from the regular consumption of fish is still controversial even after combining results from different epidemiological studies worldwide. There is a lack of data in the literature about the effect of chelation therapy in children with neurodevelopmental disabilities. Mercury poisoning should be diagnosed only with validated methods. There is no evidence to support the association between mercury poisoning and autism.
To protect children from mercury exposure
Eat a healthy, balanced diet, but limit fish that may be high in mercury, such as shark, swordfish, king mackerel and tilefish.
Throw away old thermometers that contain mercury and replace with digital thermometers.
Symptoms of chronic mercury poisoning or toxicity
Severe cases can lead to tremors and certain neurologic and psychiatric conditions such as anxiety, depression, memory loss and irritability. Some may have a rash, fever, enlarged spleen, and muscle weakness.
Testing for levels
A blood test can show levels. A normal mercury level is less than 10 micrograms/liter and less than 20Ķg/L in urine. It is best to do this testing after stopping fish consumption for a week.
Q. Are there any herbs or antioxidants such as lipoic acid, acetylcarnitine, or dmae that can neutralize mercury toxicity?
A. I have not come such research at this time. It's possible many do, I just have not seen specific research.
Q. I have not allowed any new mercury fillings to be placed in
my mouth for over 20 years now. But I do have a few small ones left that I do
not want to remove for various reasons. As they need to be removed or repaired,
they are of course, repaired without mercury. I am telling you the age of the
fillings because I have read that the mercury/vapors have a life that diminishes
over time. Therefore, it is my understanding that my mercury fillings would not
be as problematic as new ones. In the past, I have read protocols for removing
mercury and other toxic metals from the body. They say that Alpha Lipoic Acid is
very effective, but that if mercury is present, it has the ability to remove it,
but then redeposits it in the brain. I am hoping that in my case, you would
believe that I have nothing to worry about, if I want to take a reasonable daily
amount of ALA in my daily regimen. I believe I read those protocols on a website
that was treating autism. I would love to reap all of the many benefits of
taking Alpha Lipoic Acid without having to worry needlessly about damaging my
brain. Please give me your opinion on this subject.
A. I have not come across any studies regarding the role of alpha lipoic acid and mercury fillings.
Q. I am interested in lowering my body burden of mercury
and arsenic. Some of what I have read about chelation makes me doubtful of its
safety, so I am looking for other means to reduce levels of the two
aforementioned heavy metals.
A. We have not explored this topic in any great detailed knowledge yet. Many people who think their symptoms are due to arsenic or mercury poisoning may just be guessing. It is important to have two different labs confirm that a person does how toxic levels of mercury or arsenic before attributing symptoms to this toxicity.
Q. I like your website otherwise, but you should take
into account the amalgam disease, that is mercury intoxication
and the associated systemic candida - it's really widespread, but mainstream
medicine does still NOT recognize it.
For example, alpha lipoic acid is now more commonly used as a mercury chelator,
because of its disulfide group that
attaches readily to mercury atoms. Its unique ability to cross brain blood
barrier (BBB) makes it a must for mercury chelation. It is the only better known
substance to chelate mercury from brains. The synthetic chelators DMSA or DPMS
also binds to mercury, but they are not able cross BBB, and so cannot chelate
mercury out from brains or organs. The side effects for a person taking alpha
lipoic acid is what you'd expect from mobilizing mercury around in the body, as
many mercury intoxicated people can tell you, ranging from heart palpitations to
insomnia and feelings of tiredness, panic attacks, anxiety, serious depression,
and spaciness. It can also flare up candida symptoms as the
immune system gets compromised with the mercury moving around in bloodstream.
Alpha lipoic acid is potentially dangerous for people taking it in larger doses
when heavy metal poisoned, as it can redistribute metals into brain, instead of
taking them out as desired. I am also a victim of mercury poisoning, and I can
tell you that B12, at least the cyanocobalamin form is by far the most potent of
all common vitamins to cause serious side-effects (when e.g. mercury poisoned),
even potentially very dangerous ones, if taken at large doses (1 mg). My
symptoms were heart palpitations, severe chest pain, and a very high
bloodpressure (180/110), possibly even much higher initially. I do not have
heart problems (now), and im not allergic to or deficient in B12, and I do not
get adverse side-effects from it any longer, now 1 year after post-amalgam
removal. Many other substances than those mentioned here are likely to cause
mobilization of heavy metals/flare up candida, so you should keep this in mind,
when people report side-effects from vitamins etc. If people take vitamins for
their depression and find that it works, they are likely not deficient in them
to the point that it would cause depression, but rather because it helps against
metal toxicity - B12 is also a potent anti-depressant when mercury poisoned I
A. We seriously doubt that the alpha lipoic acid and B12 side effects you report are due to mercury poisoning. Most people have similar alpha lipoic acid side effects when they take high dosages and we don't think it is related to mercury poisoning.
Q. I am a medical doctor in New Zealand and have read
your article on depression including the comments from a British MD who
benefited from tryptophan supplement. However, I did not see any mention of
dental amalgam although mercury from this source has been proven to be causal
for depression, short-term memory loss and numerous other problems.
Unfortunately, it seems as if demarcation is not restricted to building sites as
MDs are not allowed to consider the teeth when making diagnoses of instigating
therapies. Our latest paper in Neuroendocrine Letters 2006 describes the
benefits of appropriate treatment namely amalgam removal with detoxification in
patients with depression, chronic fatigue and memory loss. I think it could be
important to include this factor.
A. The issue of mercury dental fillings and their health effects is a topic that I still don't have a full understanding as of December 2008.
Q. I am interested in trying glucosamine for joint pain
but I am worried that it contains mercury since it is derived from shell fish
and I've heard that some of the highest levels of mercury are in shell fish.
Does it contain any?
A. The meat of a shellfish may contain mercury but the shell is not likely to contain it and that is where glucosamine comes from.
Q. Although there are benefits to eating plenty of fish,
a lot of folks are concerned about mercury levels. What are the best
omega-3-rich fish to eat that have the lowest levels of mercury?
A. Shark, Swordfish, and King Mackerel contain high levels of mercury. It is a good idea to eat a variety of fish from different oceans and lakes. This way the level of mercury or a particular toxin exposure would be minimized since different oceans and lakes have different levels of potential pollutants.
I have been experiencing vertigo and room spinning. I
was diagnosed with benign paroxysmal positional vertigo. I also have found
information that mercury exposure can cause this syndrome. I was acutely
poisoned by mercury during a dental treatment 11 years ago and was diagnosed
with MS and Myasthenia Gravis following being struck with double vision 7 days
after having an old filling drilled out and replaced. I believe that the BPPV
has been caused by the mercury toxicity, even though I had my fillings safely
removed at the time. Are you aware of the possible relationship between mercury
toxicity and BPPV?
I am not aware of such relationship at this time.
In the newsletter dated October 2009 you write: One of
the largest groups of people who live past 100 years are found in Okinawa,
Japan. The Okinawan diet is rich in grains, vegetables and fish, a lot of fish!
In particular, cold-water varieties such as tuna, mackerel and salmon are the
most common. Most studies reveal that areas in the world that have a high rate
of centenarians have a diet that has good amounts of fish, vegetables,
mushrooms, seaweed, corn, and whole grains - and little meat. My question is, if
these people are eating a lot of these kinds of fish, why are they not dying of
Not all fish contain mercury, and perhaps the overall benefits of fish consumption outweigh potential harm from mercury excess. It is also possible that the data reflect fish consumption over several decades, and mercury presence in fish was not as high decades ago as it is now. This is a good question and more data are needed in order to give a firmer answer.
I am a 22 year old male. Since 14 years old I have had
all sorts of problems, sexual dysfunction (very reduced sperm and premature
ejaculation just to name a few), eating disorders and acid reflux and lately
even lowering of cognitive abilities and inability to understand people talking
and speaking without stops. I am quite better now since I started taking some
testosterone supplements and mercury detoxification, I am going to start a
natural herbal formula to help with my sexual problems, what I would like to ask
you is whether you have a good quality product for mercury detoxification and
other heavy metals?
We don't. Eating a healthy organic diet and reducing exposure to environmental pollutants are the best options. Certain antioxidants may be helpful such as acetylcysteine, carnosine, acetyl l-carnitine, etc. but little research is available.
I'm interested in orally taking the methylcobalamin form
of b12. I've read online that methylcobalamin can convert mercury to a more
dangerous form of methyl-mercury. Do you know if this applies to the metal
fillings in your mouth? I know that fillings have a certain percentage of
mercury and it can get into your body, but I don't know if the quantities of
either substance would be sufficient to convert the mercury into its more
We have seen no such evidence that makes us concerned.