"If mercury in fillings is stable and does not influence human health, why do autopsy studies show the level of mercury in tissues (especially the brain) directly correlates to the number of fillings in the mouth? And why are dental fillings considered toxic waste when removed from your body." - Dr Mark Hyman, founder and medical director of The UltraWellness Center and author of The UltraMind Solution.

Have you ever wondered if the fish on your plate or that old silver filling in your mouth could be quietly affecting your memory or focus? Mercury is not something most of us think about on a daily basis, yet it’s one of the most potent neurotoxins we’re exposed to in modern life. It can accumulate silently in the body over time, and for those of us who want to keep our minds sharp and resilient well into later years, understanding where mercury comes from and how to limit it is an important step in protecting our brain health.

What Is Mercury And Where Does It Come From?

Mercury is a naturally occurring heavy metal, but human activity has significantly increased its presence in our environment. Coal burning, mining, and manufacturing processes have released mercury into the air, water, and soil, making it almost impossible to avoid entirely. Mercury exists in several forms. Elemental mercury is the shiny silver liquid you may remember from old thermometers or dental amalgam fillings. Methylmercury is a highly toxic compound formed when mercury from the environment is absorbed by microorganisms and builds up in the food chain, especially in fish and seafood. Inorganic mercury compounds, once used in batteries, some cosmetics, and certain industrial products, can also contribute to exposure.

Because mercury is persistent in the environment, it accumulates in our bodies over time. While a small amount may not seem like much, regular exposure - even in low doses - can have a cumulative effect on brain health.

How Mercury Affects The Brain

One of the reasons mercury is so dangerous is that it can cross the blood-brain barrier, a protective shield that normally keeps harmful substances out of your brain. Once inside, mercury binds to brain tissue and disrupts critical neurological processes. It damages neurons, alters neurotransmitter activity, and triggers inflammation, all of which can interfere with memory, focus, and mood.

Research has linked high mercury exposure to neurological symptoms such as tremors, brain fog, depression, and slower cognitive processing. Long-term exposure may even increase the risk of neurodegenerative diseases like dementia and Parkinson’s. While most adults aren’t at risk of severe mercury poisoning, ongoing low-level exposure can still contribute to the subtle decline in mental sharpness many people experience as they age. Mercury is especially harmful during pregnancy and early childhood because developing brains are far more vulnerable, making this an important topic for parents and grandparents alike.

Common Sources Of Mercury In Daily Life

Mercury exposure can come from a surprising range of sources. One of the most significant is seafood, particularly large predatory fish like tuna, swordfish, shark, and king mackerel, which accumulate mercury as they feed on smaller fish. Dental amalgam fillings, sometimes called “silver fillings,” are another common source. While they are considered safe by many regulatory bodies, they do release small amounts of mercury vapor, especially when chewing or grinding teeth.

Compact fluorescent light bulbs (CFLs), older thermometers, and certain batteries also contain mercury. While these are safe to use if handled properly, breaking them can release toxic vapors. Some imported skin-lightening creams, herbal remedies, or cosmetics may contain mercury as well, particularly those not regulated in Western countries. Even the air we breathe can contain trace amounts of mercury due to industrial emissions.

How To Reduce Your Exposure

The good news is that there are plenty of simple ways to limit mercury exposure without feeling overwhelmed or making extreme changes. Start by choosing your seafood wisely. Fish is an excellent source of omega-3 fatty acids, which are vital for brain health, so avoiding it altogether isn’t the answer. Instead, opt for varieties naturally low in mercury, such as salmon, sardines, anchovies, and trout. If you’re a regular fish eater, it’s worth checking the Environmental Working Group or EPA guidelines to make informed choices about which types and how much to consume.

If you have old amalgam fillings, talk with your dentist about your options. Replacing them isn’t always necessary, but if you’re considering removal, ensure it’s done safely by a dentist trained in mercury-safe techniques.

Around your home, switching from CFLs to LED bulbs is a simple step that eliminates one potential mercury source. Be mindful when disposing of old thermometers, electronics, and batteries, and take advantage of local recycling schemes to prevent mercury from leaching into the environment. Avoiding unregulated skin products or herbal remedies from unknown sources is also wise, as these may contain undisclosed heavy metals.

Finally, it’s helpful to support your body’s natural detoxification systems. Eating a nutrient-dense diet rich in antioxidants, selenium, and fiber helps your body process and excrete toxins more effectively. Regular exercise, good hydration, and even gentle practices like sauna use can all support your body’s ability to eliminate heavy metals over time.

When To Seek Help

If you suspect significant mercury exposure - perhaps you have many old fillings, eat a lot of high-mercury fish, or experience unexplained neurological symptoms - testing can help bring clarity. Hair, blood, and urine tests can measure mercury levels, and a functional medicine practitioner or integrative doctor can guide you through safe detox strategies if needed.

Protecting Your Brain For The Long Term

Mercury exposure is a hidden but real threat to brain health, and it’s one of those areas where a little awareness goes a long way. By making a few small changes - choosing safer seafood, being mindful about dental care, and creating a toxin-conscious home - you can reduce your body’s mercury burden and protect your brain for the future.

The health of your brain isn’t just about adding the right foods or supplements; it’s also about limiting substances that quietly chip away at your cognitive function over time. This week, why not take a moment to reflect on where mercury may be showing up in your life and choose one simple action to reduce your exposure? Your future self - and your brain - will thank you.