Subscribe to the Magazine for free.
Subscribe for free to keep reading, If you are already subscribed, enter your email address to log back in.
Thanks for subscribing!
Oops! Something went wrong while submitting the form.
Are you a healthcare practitioner?
Thanks for subscribing!
Oops! Something went wrong while submitting the form.

A Root Cause Approach To Mercury Toxicity: A Comprehensive Guide

Medically reviewed by 
A Root Cause Approach To Mercury Toxicity: A Comprehensive Guide

Did you know that the food you eat, especially seafood, accounts for over 98% of mercury exposure in your body? This staggering statistic is a wake-up call for everyone who believes in the importance of a healthy diet. Mercury can affect multiple organ systems in the body. 

As pollution surges, mercury levels rise in tandem. Industrial activities discharge mercury into our water systems. This mercury is then transformed by bacteria and plankton into a form readily consumed by fish. Eventually, humans ingest this mercury when consuming fish. Larger fish like swordfish and sharks are exceptionally high in mercury. Put in perspective, one 4 oz portion of swordfish contains approximately 4.5 times the WHO limit of 45mcg/day. 

In this article, we're going to break down the basics of mercury: what it is, the effects of exposure, and the top tests to gauge its impact on the body. Plus, we'll share some dietary tips to counteract its effects and dive into supplements and other helpful therapies.


What is Mercury?

Mercury symbolized as "Hg" on the periodic table, exists in several states

Elemental Mercury 

This silver-white metal is liquid at room temperature and is found in dental fillings, older thermometers, and electrical equipment. If spilled, it can evaporate, becoming an odorless toxic vapor (5). 

Inorganic Mercury (Industry-Related)

Common in the environment, inorganic mercury can combine with various elements to form salts. These salts might be present in water, soil, and the atmosphere due to industrial activities. Historically used in medicines, their presence is still found in products like skin creams (5). 

Methylmercury (Found in Seafood)

Methylmercury is primarily formed when inorganic mercury, often released from industrial processes, enters aquatic environments like rivers and seas. In these waters, bacteria and plankton undertake a process that transforms this inorganic mercury into methylmercury. As a result, aquatic organisms, starting from the smallest microbes and reaching up to the larger predatory fish, begin to accumulate this toxin. Over time, this leads to the bioaccumulation of methylmercury in larger fish species that sit atop the aquatic food chain. When humans consume these contaminated fish, they, too, become exposed to this potent form of mercury (5). 

What is Mercury Toxicity?

Mercury toxicity describes the adverse reactions resulting from excessive mercury exposure. Mercury toxicity and mercury poisoning, though closely linked, are not identical. Mercury toxicity describes the detrimental consequences of mercury exposure, while mercury poisoning is a specialized condition resulting from an excessive amount of mercury contact.

A predominant cause of toxicity is the consumption of methylmercury, often found in seafood. The severity and type of health consequences from mercury depend on factors like the mercury form, amount of exposure, age of the individual, duration of contact, method of exposure, and one's overall health. Both elemental and methylmercury pose risks, potentially impacting the nervous, digestive, and immune systems, as well as the lungs and kidneys. In extreme situations, prolonged mercury exposure can lead to irreversible lung and potential brain harm (7). 

Mercury Toxicity Signs & Symptoms

Signs and symptoms for mercury toxicity change depending on the patient profile, the type of mercury, and the length or quantity of exposure. Some patients with chronic low-grade mercury exposure may be asymptomatic (7,9,10). 

  • Anxiety or unease
  • Mood fluctuations or irritability
  • Loss of sensation
  • Challenges with memory
  • Insomnia
  • Shaking or tremors
  • Weakness in muscles
  • Feeling sick or throwing up
  • Unsteadiness or lack of coordination
  • Numbness in areas like the hands or face
  • Alterations in sight, sound, or verbal communication
  • Challenges with respiration
  • Trouble maintaining posture or walking
  • Diminished motor function
  • Cognitive challenges or difficulty in decision-making

What Are The Possible Causes Of Mercury Toxicity?

The causes of mercury toxicity are dependent upon the exposure type. Studies have shown that the major contributor to mercury exposure in humans is the ingestion of food (usually seafood), accounting for over 98% of mercury exposure (1).


Methylmercury is most often associated with seafood. While most dietary sources contain relatively low mercury levels, seafood, particularly fish and shellfish, often have much higher concentrations. An estimated 90% of the mercury in seafood is in the form of methylmercury. Further emphasizing its potency, research suggests that when methylmercury enters the human system, as much as 95% of it can remain, showcasing its significant tendency for bioaccumulation. As a result, individuals, especially those who consume a lot of seafood, should be cautious and informed about their potential intake (6). 

Methylmercury’s absorption rates are alarmingly high: over 95% in the gastrointestinal system and around 80% through respiratory pathways. Post absorption, it spreads across all bodily tissues within a mere 30 hours. Notably, the elimination of methylmercury is primarily fecal, with roughly 90% being expelled via bile into the feces and a minor portion, less than 10%, excreted in urine. The compound's persistence is evident in its half-life, which spans between 45 to 70 days (9). 

Products and Dental Fillings

The most common exposures to elemental mercury occur when mercury is released from a broken container, product, or device, allowing it to evaporate into an invisible, toxic vapor. Potential sources include broken fever thermometers, novelty jewelry, various consumer products, dental amalgams, and certain mining practices (11). 

People sometimes worry about mercury exposure from dental fillings. Dental amalgams, used for nearly a century, release a tiny amount of mercury (2-20 mcg/day) during actions like chewing. Chewing gum can increase this release. Mouth bacteria convert some of this mercury into forms that the body absorbs. However, the mercury from fillings is below the World Health Organization's daily safety standard of 45 mcg/day. For perspective, while many foods contain minimal mercury, some game fish have levels exceeding 2.0 mcg/g, making fish a more common mercury source for many individuals (13). 

Other Exposures

Other mercury compounds, like phenylmercury acetate and ethylmercury, were previously widespread in fungicides, preservatives, and antiseptics. While many of their applications have been discontinued, some still exist. Furthermore, mercury is still present in some skin-lightening and anti-aging products manufactured abroad but sold illegally in the U.S. Overusing or misusing these products, especially older ones with higher mercury concentrations, can lead to excessive mercury exposure (11). 

Functional Medicine Labs to Test for Root Cause of Mercury Toxicity

Functional medicine labs offer a variety of tests that can help tailor treatment to patients, allowing providers to optimize management strategies.

Heavy Metal Testing

When testing for mercury exposure, it's important to remember that levels found in blood, hair, and urine mainly show recent exposure and don't truly represent the total mercury present in the entire body. Since mercury stays in the blood for only about three to five days before it's either expelled or settles in organs, levels found in testing may not truly reflect total body burden (7).

Heavy Metal Testing - Urine

Urine tests are primarily useful for those who might have been exposed to metallic or inorganic mercury compounds. The advantage of urine tests is their stability and simplicity. Inorganic mercury is predominantly reflected in urine, whereas organic forms like methylmercury are primarily excreted through feces. Persistent high concentrations in the urine can indicate long-term exposure. Concentrations beyond 100 μg/L might lead to neurological issues, and levels above 800 μg/L can be lethal (9). 

Heavy Metal Testing - Blood

When an individual is suspected of recent mercury exposure or consumes seafood regularly, blood mercury concentration testing is advisable. This is because blood levels can provide insight into both recent and chronic mercury exposure. Shortly after a brief exposure, blood mercury concentrations spike, necessitating immediate testing. For those who've experienced chronic exposure, even after ceasing contact with the source, blood mercury levels can remain elevated. Normal whole blood mercury is usually below 10 ng/mL (9,12). 

Heavy Metal Testing - Hair

Hair tests assess chronic exposure to methylmercury and are especially recommended for pregnant women, as elevated levels (above 10 ppm) can pose a neurological risk to the fetus. Mercury's presence in hair is a long-term indicator, as once mercury binds to the hair, it remains permanently. Typically, mercury concentrations in hair shouldn't surpass 10 mg/kg, but in cases of moderate to severe poisoning, these levels can range from 200 mg/kg to 2400 mg/kg respectively (9). 

Comprehensive Stool Test

Exposure to toxic metals, like mercury, can disrupt gut microbiota and target the gut as a primary tissue, leading to imbalances known as dysbiosis. A comprehensive gastrointestinal test, which measures microbiota imbalances and gut integrity markers like zonulin, is helpful for assessing the impact of mercury on gut health, as mercury exposure has also been shown to negatively impact intestinal barrier function. Utilizing such a test can help guide therapeutic interventions to restore gut balance after exposure.

Nutritional Testing

Nutritional assessment is a valuable tool for identifying potential deficiencies that may enhance susceptibility to mercury toxicity. Evaluating the levels of key nutrients like selenium and zinc can provide insights into their contribution to mercury detoxification in the body.

Organic Acid Testing

Organic acid testing can help identify imbalances in detoxification or metabolic pathways that may be contributing to mercury toxicity. This test measures the levels of organic acids in the urine, which can provide insight into how the body is metabolizing nutrients and detoxifying harmful substances.

Hs-CRP Testing

Studies have shown a correlation between elevated inflammation in the body and mercury exposure. 

Additional Lab Tests 

For a comprehensive evaluation of potential mercury intoxication, a series of clinical laboratory tests might be prescribed. While most outpatient tests offer a general mercury measure without differentiating its forms, additional assessments, including renal and hepatic function tests, ECG, and neuropsychological evaluations, can provide a broader picture. These results can be influenced by factors other than mercury, so it's essential to interpret them in conjunction with known exposure and observed symptoms (9). 


Conventional Treatment for Mercury Toxicity

When there's a suspicion of mercury toxicity in a patient, conventional treatment focuses on obtaining a comprehensive history of their exposure, identifying and eliminating any ongoing sources of mercury, and rigorously monitoring their respiratory and cardiovascular systems. For less symptomatic cases, removal of the source of mercury is advised. If there's evidence of inorganic mercury ingestion, monitoring its progression through the GI tract using X-rays is vital, and any resultant symptoms should be treated as one would for corrosive ingestion. Chelating agents, particularly DMSA, are often the first line of treatment, especially for severe methylmercury cases, due to their minimized side effects (9). 

Functional Medicine Treatment for Mercury Toxicity

In functional medicine, we prioritize a multifaceted treatment plan for mercury toxicity. This entails a combination of targeted nutrition, supplements, and complementary practices. 

Nutrition To Help Treat Mercury Toxicity

Mercury exposure, predominantly from seafood, poses a significant threat to human health due to its easy absorption in the gastrointestinal (GI) tract. With over 95% of ingested methylmercury being absorbed, there's evident damage to the gut, leading to conditions like "leaky gut" syndrome. This not only compromises the gut barrier but can cascade into a myriad of other health issues. 

Addressing mercury toxicity nutritionally encompasses two main strategies: firstly, limiting mercury intake by opting for low-mercury fish, and secondly, actively healing the gut. The role of gut bacteria is crucial in this context. A healthy gut microbiome plays a pivotal role in mitigating the adverse effects of mercury. Studies have demonstrated that the absence of beneficial gut bacteria accelerates the accumulation of mercury in critical organs such as the brain, liver, and lungs (9). 

In the face of mercury-induced gut damage, embracing a nutrient-rich diet is a critical part of fixing the gut. Anti-inflammatory diets serve as an excellent starting point, focusing on foods that combat inflammation, such as leafy greens, berries, nuts, and fatty fish. These foods not only provide essential nutrients but also aid in repairing damaged gut lining. Similarly, the Mediterranean diet, characterized by its high consumption of fruits, vegetables, whole grains, and olive oil, coupled with moderate fish and poultry intake, can be invaluable. Rich in antioxidants and omega-3 fatty acids, the Mediterranean diet promotes a balanced and diverse gut microbiome, aiding in both healing the gut and reducing the overall toxicity of mercury in the body.

Supplements & Herbs To Help Treat Mercury Toxicity

Supplements that may help with the effects of mercury toxicity include:


Mercury can disrupt gut health by inhibiting beneficial bacteria like Lactobacillus. Probiotics may counteract this effect by replenishing healthy bacteria levels in the gut.


Mercury has a notably high binding affinity to selenium, causing it to attach strongly to selenium when it enters the body. Selenium, found in various foods such as Brazil nuts, can cause a "sink" effect, redirecting mercury away from the brain, a primary target for mercury toxicity. This binding action serves as a protective mechanism, reducing mercury's harmful body effects. Notably, while high mercury exposure can hinder selenium-dependent enzyme activities in fetal brains, increased selenium in the maternal diet can counteract this. Therefore, when assessing mercury exposure risks, it's vital to factor in selenium intake and its distribution in tissues.


Zinc plays a protective role against mercury toxicity. Studies have shown that even after prolonged exposure to mercury, zinc can counteract its harmful biochemical effects. Interestingly, individuals with higher mercury levels often exhibit reduced zinc and copper levels. Both metals bind to metallothionein, but zinc's presence may prevent mercury from displacing them, further showcasing its defensive role against mercury's adverse effects.


Glutathione may offer protection against the neurological and renal damage caused by mercury. Beyond its antioxidant properties, glutathione binds to heavy metals like mercury, assisting in their detoxification. The protective and detoxifying roles of glutathione emphasize its significance in combating mercury toxicity.

Complementary and Integrative Medicine To Help Treat Mercury Toxicity

Mercury toxicity is linked to heightened inflammation in the body. Stress-reducing methods like yoga, deep breathing, and meditation can potentially counteract these effects. In addition, regular exercise can also reduce stress and inflammation levels in the body. Therefore, these techniques may indirectly diminish the inflammation associated with mercury exposure (19). 

Saunas, which have been an integral part of various cultures worldwide, promotes sweating and could be a beneficial tool for aiding mercury detoxification. A small study hints that the human body might excrete mercury through sweat, sometimes even more effectively than through urine. 



In summary, mercury exposure, predominantly from seafood, presents a significant risk to human health due to its high absorption rate and detrimental effects on various organ systems. Mercury, found in varying forms like elemental mercury, inorganic mercury, and particularly methylmercury, accumulates in seafood, making it the primary source of human exposure. Mercury toxicity encompasses the adverse outcomes from this exposure, with a distinct difference from mercury poisoning, which denotes an acute overexposure. Testing for mercury levels involves diverse techniques, from heavy metal testing to comprehensive stool and nutritional testing, highlighting its widespread effects on the body.

Conventional treatments for mercury toxicity focus on history, source removal, and essential monitoring, with chelating agents like DMSA at the forefront for severe cases. However, functional medicine brings a holistic lens, emphasizing the importance of targeted nutrition, such as anti-inflammatory and Mediterranean diets, and the pivotal role of a healthy gut microbiome. Supplements like probiotics, selenium, zinc, and glutathione offer an additional defense, addressing mercury's effects on the gut and broader systems. Complementary practices, such as stress-reducing techniques and regular exercise, further support the body's resilience against mercury's inflammatory impact.

The information provided is not intended to be a substitute for professional medical advice. Always consult with your doctor or other qualified healthcare provider before taking any dietary supplement or making any changes to your diet or exercise routine.
Learn More
No items found.

Lab Tests in This Article


  1. Ye, B. J., Kim, B. G., Jeon, M. J., Kim, S. Y., Kim, H. C., Jang, T. W., Chae, H. J., Choi, W. J., Ha, M., & Hong, Y. S. (2016, January 22). Evaluation of mercury exposure level, clinical diagnosis and treatment for mercury intoxication. Annals of Occupational and Environmental Medicine; BioMed Central.
  2. Mercury and Your Body. (n.d.).
  3. De Paula Arrifano, G., Augusto-Oliveira, M., Lopes-Araújo, A., Santos-Sacramento, L., De Matos Macchi, B., Nascimento, J. L. M. D., & Crespo-Lopez, M. E. (2023, February 27). Global Human Threat: The Potential Synergism between Mercury Intoxication and COVID-19. International Journal of Environmental Research and Public Health; Multidisciplinary Digital Publishing Institute.
  4. Mercury, Blood - Mayo Clinic Laboratories | Neurology Catalog. (n.d.).
  5. Basic Information about Mercury | US EPA. (2022, December 21). US EPA.
  6. Hong, Y. S., Kim, Y. M., & Lee, J. Y. (2012, November 29). Methylmercury Exposure and Health Effects. Journal of Preventive Medicine and Public Health; Korean Society for Preventive Medicine.
  7. Bernhoft, R. A. (2012, January 1). Mercury Toxicity and Treatment: A Review of the Literature. Journal of Environmental and Public Health; Hindawi Publishing Corporation.
  8. Health Effects of Exposures to Mercury | US EPA. (2023, March 28). US EPA.
  9. Ye, B. J., Kim, B. G., Jeon, M. J., Kim, S. Y., Kim, H. C., Jang, T. W., Chae, H. J., Choi, W. J., Ha, M., & Hong, Y. S. (2016, January 22). Evaluation of mercury exposure level, clinical diagnosis and treatment for mercury intoxication. Annals of Occupational and Environmental Medicine; BioMed Central.
  10. Mercury exposure and poisoning. (n.d.). Better Health Channel.
  11. How People are Exposed to Mercury | US EPA. (2023, March 28). US EPA.
  12. Mercury, Blood - Mayo Clinic Laboratories | Neurology Catalog. (n.d.).,up%20to%2015%20ng%2FmL.
  13. Mercury in Dental Amalgam | US EPA. (2023, February 21). US EPA.
  14. Singh, S., Sharma, P., Pal, N., Kumawat, M., Shubham, S., Sarma, D. K., Tiwari, R. R., Kumar, M., & Nagpal, R. (2022, July 19). Impact of Environmental Pollutants on Gut Microbiome and Mental Health via the Gut–Brain Axis. Microorganisms; Multidisciplinary Digital Publishing Institute.
  15. Xue, T., Lin, X., Zhao, J., Cui, L., Gao, Y., Yu, Y. L., Li, B., & Li, Y. (2023, January 1). Gut as the target tissue of mercury and the extraintestinal effects. Toxicology; Elsevier BV.
  16. DeCesaris, L. (2023, March 2). What Is Gut Dysbiosis? 7 Signs To Watch For. Rupa Health.
  17. Pinto, D., Da Silva Raposo, R., Matos, G. A., Alvarez-Leite, J. I., Malva, J. O., & Oriá, R. B. (2020, November 3). Methylmercury Interactions With Gut Microbiota and Potential Modulation of Neurogenic Niches in the Brain. Frontiers in Neuroscience; Frontiers Media.
  18. Tinggi, U., & Perkins, A. V. (2022, December 14). Selenium Status: Its Interactions with Dietary Mercury Exposure and Implications in Human Health. Nutrients; Multidisciplinary Digital Publishing Institute.
  19. Lim, S. G., Ha, M., Hong, Y. C., Leem, J. H., Sakong, J., Kim, S., Lee, C., Dh, K., Oh, S. M., & Kwon, H. J. (2008, November 1). Mercury Effect on Blood Pressure through hs-CRP in Children. Epidemiology; Lippincott Williams & Wilkins.
  20. Cloyd, J. (2023, April 28). A Functional Medicine Protocol for Leaky Gut Syndrome. Rupa Health.
  21. Seki, N., Akiyama, M., Yamakawa, H., Hase, K., Kumagai, Y., & Kim, Y. G. (2021, January 1). Adverse effects of methylmercury on gut bacteria and accelerated accumulation of mercury in organs due to disruption of gut microbiota. Journal of Toxicological Sciences; Japanese Society of Toxicological Sciences.
  22. Blake, K. (2023, June 8). Anti Inflammatory Diet 101: What to Eat and Avoid Plus Specialty Labs To Monitor Results. Rupa Health.
  23. Weinberg, J. L. (2023, March 2). What is The Mediterranean Diet? Rupa Health.,fatty%20liver%20disease%20(NAFLD).
  24. Seki, N., Akiyama, M., Yamakawa, H., Hase, K., Kumagai, Y., & Kim, Y. G. (2021, January 1). Adverse effects of methylmercury on gut bacteria and accelerated accumulation of mercury in organs due to disruption of gut microbiota. Journal of Toxicological Sciences; Japanese Society of Toxicological Sciences.
  25. Berry, M. J., & Ralston, N. V. (2008, December 1). Mercury Toxicity and the Mitigating Role of Selenium. Ecohealth; Springer Science+Business Media.
  26. Franciscato, C., Moraes-Silva, L., Duarte, F. A., Oliveira, C. S., Ineu, R. P., Flores, E. M., Dressler, V. L., Peixoto, N. C., & Pereira, M. E. (2011, March 1). Delayed biochemical changes induced by mercury intoxication are prevented by zinc pre-exposure. Ecotoxicology and Environmental Safety; Elsevier BV.
  27. Mercury toxicity and antioxidants: Part 1: role of glutathione and alpha-lipoic acid in the treatment of mercury toxicity. (2002, December 1). PubMed.
  28. Jan, A. T., Ali, A., & Haq, Q. M. R. (2011, January 1). Glutathione as an antioxidant in inorganic mercury induced nephrotoxicity. Journal of Postgraduate Medicine; Medknow.
  29. Rubino, F. M. (2015, January 26). Toxicity of Glutathione-Binding Metals: A Review of Targets and Mechanisms. Toxics; Multidisciplinary Digital Publishing Institute.
  30. Maholy, N. (2023, April 17). How to Reduce Stress Through Mind-Body Therapies. Rupa Health.
  31. Malani, S. (2023, July 5). Inflammatory Markers 101: How To Interpret. Rupa Health.!,affect%20both%20CRP%20and%20NLR.
  32. Sears, M., Kerr, K., & Bray, R. I. (2012, January 1). Arsenic, Cadmium, Lead, and Mercury in Sweat: A Systematic Review. Journal of Environmental and Public Health; Hindawi Publishing Corporation.
  33. Neibling, K. (2023, August 24). Functional Medicine Heavy Metal Detox Protocol: Testing, Diagnosing, and Treatment. Rupa Health.,such%20as%20alcohol%20or%20Tylenol.
  34. Genuis, S. J., Birkholz, D., Rodushkin, I., & Beesoon, S. (2010, November 6). Blood, Urine, and Sweat (BUS) Study: Monitoring and Elimination of Bioaccumulated Toxic Elements. Archives of Environmental Contamination and Toxicology; Springer Science+Business Media.
  35. Sweetnich, Dr. J. (2023b, March 22). Selenium 101: Testing, Top Foods, and Supplements. Rupa Health.
  36. Sweetnich, Dr. J. (2023f, April 5). Health Benefits of Zinc. Rupa Health.
  37. Deporto, T. (2023, January 31). Glutathione Health Benefits: The Master Antioxidant. Rupa Health.
Subscribe to the Magazine for free. to keep reading!
Subscribe for free to keep reading, If you are already subscribed, enter your email address to log back in.
Thanks for subscribing!
Oops! Something went wrong while submitting the form.
Are you a healthcare practitioner?
Thanks for subscribing!
Oops! Something went wrong while submitting the form.