Nutrition Diet: Can Your Body Get Rid of Mercury From Fish?

October 17, 2025 •

4 min read

Methylmercury can accumulate in the bloodstream, taking over a year for levels to drop significantly after regular consumption of high-mercury fish. This raises a critical question for many health-conscious individuals: can your body get rid of mercury from fish, and if so, how effectively?

Quick Summary

The human body possesses a natural, albeit slow, detoxification system for eliminating mercury through the liver, kidneys, and waste products. The elimination rate depends on exposure and an individual's health. Dietary choices, especially consuming low-mercury fish and high-selenium foods, are essential for managing intake and supporting this process.

Key Points

Natural Elimination is Slow: The body naturally removes mercury through the liver and kidneys, but the process for methylmercury from fish can take over a year.
Know Your Fish Choices: Limit or avoid high-mercury fish like swordfish and shark, and prioritize low-mercury options such as salmon and sardines.
Selenium Offers Protection: The mineral selenium binds with mercury, forming an inert compound that reduces its toxicity and prevents harm to the body.
Diet and Hydration Help: A diet rich in antioxidants and fiber supports detoxification, while drinking plenty of water assists the kidneys in flushing toxins.
Sweat Out Toxins: Practices like exercise and using an infrared sauna can promote the elimination of heavy metals, including mercury, through sweat.
Chelation for Severe Cases: For actual mercury poisoning, medical treatment with chelating agents is necessary to remove high levels of the metal from the body.

The Science Behind Mercury in Fish

Mercury is a naturally occurring element that enters the environment through volcanic activity and human industrial processes. Once in the water, it is transformed by bacteria into methylmercury, a highly toxic form that accumulates in fish and shellfish. This process is known as biomagnification, where larger, predatory fish at the top of the food chain—like sharks and swordfish—have higher concentrations of methylmercury. As a result, when you eat fish containing methylmercury, you also ingest the mercury, which can build up in your bloodstream over time.

Your Body's Natural Detoxification System

Your body has a natural filtration system designed to process and remove toxic substances, primarily involving the liver and kidneys. After ingesting methylmercury, it is slowly processed and eventually eliminated from the body through urine, stool, and breast milk.

However, this is not a rapid process. For methylmercury, the elimination can be very slow, and it may take a year or more for blood levels to decrease significantly, even after exposure has ceased. The effectiveness of this natural process depends on several factors, including the level of exposure, the duration of that exposure, and the overall health of your liver and kidneys. For most people with average fish consumption, the body's natural system is sufficient. However, high exposure levels, especially for vulnerable populations like pregnant women and children, can overwhelm the system and pose health risks.

The Mercury and Selenium Connection

Interestingly, the story of mercury in fish is not just about a toxic metal; it also involves the crucial mineral selenium. Selenium has a strong binding affinity for mercury and can play a protective role in the body. This interaction works by:

Forming Inert Complexes: Selenium binds to mercury, forming a stable, non-toxic compound that the body cannot easily absorb. This process effectively neutralizes the mercury, preventing it from damaging tissues.
Protecting Selenoenzymes: Mercury exerts its toxic effects by inhibiting selenium-dependent enzymes, which are vital for antioxidant function. By sequestering mercury, selenium helps preserve the activity of these crucial enzymes.
Influencing Fish Toxicity: The levels of both mercury and selenium in fish are important. Some fish naturally contain high levels of selenium, which may mitigate the toxic effects of their mercury content.

High-Mercury vs. Low-Mercury Fish: A Comparison

Making informed choices at the seafood counter is one of the most effective ways to manage your mercury intake. The following table compares fish species based on their typical mercury levels, helping you choose safer options.


Fish Species	Mercury Level	Recommendation (FDA)	Key Considerations
High-Mercury Fish	High	Avoid or limit	Generally larger, longer-living, and predatory fish.
Swordfish	0.995 ppm	Avoid	Large predator, accumulates high levels of methylmercury.
Shark	0.979 ppm	Avoid	Top predator, significant accumulation.
King Mackerel	0.730 ppm	Avoid	Large size and predatory nature contribute to high levels.
Tilefish (Gulf of Mexico)	1.123 ppm	Avoid	Known for having some of the highest mercury content.
Bigeye Tuna	0.689 ppm	Limit	Higher mercury than other tuna types; limit consumption.
Low-Mercury Fish	Low	Best Choice	Generally smaller, shorter-lived fish lower on the food chain.
Salmon	0.012 ppm	Best Choice	A low-mercury option rich in Omega-3 fatty acids.
Sardines	Low	Best Choice	Small, short-lived fish with minimal mercury accumulation.
Hake	Low	Best Choice	Lower mercury content than other marine fish.
Pollock	Low	Best Choice	Widely consumed, with low mercury levels.
Trout	Low	Best Choice	Low mercury, especially freshwater varieties.

Dietary and Lifestyle Strategies to Support Detoxification

Beyond simply choosing lower-mercury fish, you can support your body's natural detoxification processes through a nutrient-rich diet and healthy lifestyle habits:

Dietary Support:

Increase Antioxidant-Rich Foods: Mercury can cause oxidative stress, so consuming foods rich in antioxidants, like leafy greens, berries, and cruciferous vegetables, can help combat cellular damage.
Boost Fiber Intake: Fiber binds to toxins in the digestive tract, aiding in their removal. Flaxseeds, chia seeds, and other high-fiber foods are excellent for this purpose.
Include Selenium-Rich Foods: In addition to selecting fish with favorable mercury-to-selenium ratios, you can increase your selenium intake from sources like Brazil nuts, eggs, and fortified grains.
Stay Hydrated: Drinking plenty of water is crucial for proper kidney function, which is a key pathway for eliminating toxins, including mercury.

Lifestyle Adjustments:

Consider Sweating Therapies: Regular exercise and infrared saunas can help eliminate heavy metals, including mercury, through sweat. Infrared saunas, in particular, may promote deeper tissue penetration and enhanced toxin release.
Support Gut Health: A healthy gut microbiome plays a role in detoxification. Consuming probiotics can help maintain a balanced gut, which may aid in reducing mercury absorption.

When to Seek Medical Advice

While natural methods can support your body's normal processes, they are not a substitute for professional medical treatment in cases of actual mercury poisoning. If you suspect you have high mercury levels or are experiencing symptoms of toxicity, consult a healthcare provider. Medical treatment for serious mercury poisoning often involves chelation therapy, where medications known as chelators bind to heavy metals and help remove them from the body.

Conclusion

So, can your body get rid of mercury from fish? Yes, it can, but it is a slow process that is most effective when mercury exposure is limited. By choosing low-mercury fish, supporting your body's natural detoxification pathways through a nutrient-rich diet, and staying hydrated, you can enjoy the many benefits of fish without undue concern over mercury accumulation. Pregnant women, breastfeeding mothers, and young children should be particularly mindful of their choices, following guidelines from health organizations like the FDA to ensure the safest consumption. Informed choices, combined with a healthy lifestyle, are the best defense against mercury buildup.

Here is some helpful advice from the FDA on making smart seafood choices.

Frequently Asked Questions

The body can take over a year to significantly lower its levels of methylmercury, even after exposure has been stopped. The process is slow and depends on the amount of mercury accumulated.

Safest options include smaller fish like salmon, sardines, pollock, and trout. These fish are lower on the food chain and accumulate less methylmercury.

While some studies suggest these may have binding properties, robust clinical evidence is lacking for their ability to reliably and significantly lower mercury levels in humans. They may, however, offer some protective effects.

Chelation therapy is a medical procedure used for serious mercury poisoning. It involves medication and is only administered under a doctor's supervision due to potential side effects.

Some studies suggest that infrared saunas, through promoting sweat, can help eliminate heavy metals like mercury from the body. However, it is not a cure for poisoning.

High levels of mercury can harm the developing brain and nervous system in fetuses and young children. Health authorities recommend that these groups be especially careful about consuming high-mercury fish.

No, mercury is tightly bound to the proteins in fish tissue. Cooking methods do not effectively reduce the mercury content of fish.