Can Mercury Cause Tinnitus?

Mercury is a toxic metal found in the environment, in some fish, and in older "silver" dental fillings. High levels of mercury can harm the nervous system, including the parts of the body involved in hearing. So can mercury cause tinnitus? In cases of real mercury poisoning, it can. For most people, though, everyday exposure is not a likely cause.

How mercury affects the body

Mercury comes in different forms. Methylmercury, the type that builds up in fish, is the main concern for most people. It can cross into the brain and, at high doses, damage nerve cells. Symptoms of mercury poisoning can include:

• Tingling or numbness in the hands, feet, or around the mouth
• Problems with coordination and balance
• Vision changes
• Hearing loss and ringing in the ears
• Memory problems, irritability, or mood changes

The Minamata lesson

The clearest evidence comes from Minamata, Japan, where a factory released methylmercury into the bay in the 1950s. People who ate the local fish developed what became known as Minamata disease, which included hearing impairment along with problems with movement, speech, and vision. This was a case of extreme, long-term exposure, far higher than most people ever encounter.

What about fish?

Fish is a healthy food, and most people do not need to avoid it. To keep mercury exposure low, the FDA and EPA suggest choosing lower-mercury fish like salmon, sardines, shrimp, and canned light tuna, and limiting high-mercury fish like king mackerel, swordfish, shark, and bigeye tuna. This matters most for pregnant women, people who may become pregnant, and young children.

What about dental fillings?

Amalgam fillings contain mercury and release tiny amounts of vapor, especially when chewing. There is no good evidence that amalgam fillings cause tinnitus.

In 2020 the FDA recommended that certain higher-risk groups avoid getting new amalgam fillings when a good alternative is available. That includes pregnant and nursing women, children under six, and people with kidney problems, certain neurological conditions, or a known mercury allergy. The FDA does not recommend removing existing fillings that are in good condition. Drilling them out can actually release more mercury vapor for a short time.

Testing and treatment

If you think you have had significant mercury exposure, ask your doctor about blood or urine testing. Treatment for confirmed poisoning, such as chelation therapy, should only be done under medical supervision. The FDA has warned against over-the-counter chelation products, which are not approved and can be dangerous.

The bottom line

Mercury poisoning can affect hearing, but it is an uncommon cause of tinnitus. If you have new ringing in your ears, start with a hearing test and a checkup. Noise exposure, hearing loss, earwax, and medications are far more common causes.