Manganese, Hearing Loss and Tinnitus

by Neil Bauman, Ph.D.

A man wrote,

I have heard that a toxic load of certain minerals such as manganese can cause ear problems including tinnitus. This is interesting as manganese is also used for treating tinnitus.

My multivitamin contains 2 mg of manganese. Is it time to look for another vitamin supplement? There seems to be a toxic level. The Linus Pauling Site has 11 mg for an upper limit for adults. What would be considered hearing-damaging and toxic levels of manganese? There are supplements out there with more than 11 mg in them, and I obviously got caught up in taking one. I am looking for ways to get the manganese out of my body so my tinnitus will die down.

If you are only taking a 2 mg manganese supplement daily, it would be pretty hard to get an overdose of manganese. Let me explain.

Manganese is an essential trace mineral. This means it is necessary for normal growth and development. The key here is that it is a trace mineral. In other words, we need small amounts of manganese in order to function properly. However, too much of a good thing can quickly become a bad thing. Thus, the trick is to make sure you get enough manganese, but not too much.

The daily optimal intake of manganese is not known. (1) The Institute of Medicine (IOM) of the U.S. National Academy of Sciences has not set a Recommended Dietary Allowance (RDA) (or the newer Dietary Reference Intake [DRI]) for manganese.

However, the adequate intake (AI) level for manganese is listed at 2.3 mg per day for men and 1.8 mg for women. (1) Many multi-vitamin/multi-mineral supplements, such as yours, provide 2 mg of manganese in addition to what you get in the food you eat. The estimated safe and adequate daily intake of manganese is considered 2.5 mg to 5.0 mg. (2) For sources of manganese other than from natural foods, the conservative tolerable upper intake level for manganese in adults is 11 mg per day. (1) You are well inside that limit so you shouldn’t have a problem.

Some estimate we get between 2.5 and 7 mg of manganese in the typical American diet. However, if you eat mostly raw, unprocessed foods, your diet will be much higher in manganese. (3)

How much manganese you get depends on what you eat. If you eat whole grains, vegetables and fruit you will get adequate amounts of manganese without a need for taking supplements.

Natural sources of manganese in your diet include green leafy vegetables—spinach, beets, Brussels sprouts; the outer coating (bran) of nuts (pecans, almonds, peanuts) and grains (oats, wheat); fruits such as pineapple, blueberries, oranges, grapefruit, apricots; green tea, etc.

Incidentally, here’s some good news. You can’t get too much manganese from eating natural foods. “There is no evidence that the consumption of a manganese-rich plant-based diet results in manganese toxicity” (1) and, even if you eat natural foods that are high in manganese, manganese toxicity has not been reported even though you may be getting up to 20 mg of manganese or more a day. (1)

Here’s some more interesting information on manganese.

Why We Need Manganese

Manganese is an important component of several enzymes. As a result, “manganese plays an important role in a number of physiologic processes as a constituent of multiple enzymes and an activator of other enzymes.” (1) For example, “manganese is necessary for processes controlling reproduction, formation of connective tissue and bone, carbohydrate and lipid metabolism and brain function.” (4)

That is why a manganese deficiency can cause abnormal bone development and deformities, poor equilibrium as well as a number of other things.

Lack of Adequate Manganese

Very little is written about how a lack of manganese affects the auditory system. However, some alternative health care practitioners feel that a lack of manganese can cause tinnitus and other ear disorders.

If tinnitus is the result of a lack of dietary manganese, they suggest taking 5 mg of manganese as “a dietary supplement that may be a helpful adjunct therapy in treating tinnitus or hearing loss”. (5)

Since most people have an adequate intake of manganese, I doubt that very many people have tinnitus caused by a lack of manganese, but I’m sure it is possible.

For example, I read that “if when you first noticed the ringing, it was occurring on the left side, the odds are very high you are low in the mineral manganese. If this is the case, you may also be experiencing muscle aches or joint aches, maybe even some carpal tunnel problems if you have a type of job that causes you to do a repetitive motion.” (6)

Further down this page, I also found, “Donald Lepore, N.D. found that what ear the tinnitus occurs in is an indication to what is wrong. He found that tinnitus in the left ear is usually caused by an allergy to rice and the “rice allergy food group” which consists of cinnamon, blueberries, grapes, rice, strawberries, watermelon, wine, and pumpkins. This allergy can be corrected with the mineral manganese, vitamin B-6, and the amino acid Arginine.” (6)

I don’t know how true the above is—I have no personal experience with it, but if your tinnitus occurs only in your left ear for no apparent reason, you might want to make sure you are getting adequate manganese in your diet, or take a supplement with about 5 mg of manganese in it and see whether this reduces or eliminates your tinnitus. (If you have such an experience, I’d love to hear about it.)

Manganese Toxicity

In your case, you are worried that your tinnitus is being caused by an excess of manganese. What makes you think that your tinnitus is being caused by taking too much manganese, and not from some other cause?

The truth is, most people get enough manganese in their diets (and/or multi-vitamin/multi-mineral supplements) so a lack of manganese is typically not a problem. However, when it comes to sources of manganese apart from natural foods, manganese toxicity can be a real possibility. If you get too much manganese, problems arise—especially nervous system problems. (5)

Manganese toxicity (called manganism—MAN-gah-nih-zem) may result in a number of neurological problems that generally appear slowly over a period of months to years. (1) Too much manganese in your body causes neurological symptoms similar to those in Parkinson’s disease as well as resulting in damage to other organs including the auditory system, which can result in hearing loss, according to epidemiological studies and case reports. (1, 7)

Manganese accumulates in your inner ears. (4) There, it is more toxic to the inner hair cells than the outer hair cells. Furthermore, damage to the inner hair cells is relatively uniform along the length of the cochlea. (4) This results in a “flat” hearing loss (same degree of hearing loss across all frequencies). This may be more accurate than an earlier report that hearing loss from manganese occurs in both the high and low frequencies, leaving you with an inverted cookie-bite kind of loss. (8)

Too much manganese in your inner ears can cause significant damage to the hair cells and their underlying spiral ganglion neurons. If a hair cell dies, the sound wave for that frequency is never converted to an electrical signal so you don’t hear it. If the underlying spiral ganglion neurons die, then the electrical signal generated by the hair cell is not transmitted to the auditory nerve, so again, you don’t hear that signal. (4) One study showed that the higher the concentration of manganese and the longer you are exposed to manganese, the greater the damage to your inner ears. (4)

Furthermore, manganese is a heavy metal that interacts synergistically with noise exposure to cause increased hearing loss. In one study, workers exposed to both noise and manganese had accelerated hearing loss compared to those exposed to manganese alone. (8)

Manganese is a well-recognized health hazard for people who work in environments with protracted high atmospheric levels of this mineral. This includes workers who regularly inhale manganese dust and fumes such as arc welders, manganese miners and people working in ferroalloy processing (smelter workers). (4)

Arc welders, for example, are susceptible to hearing loss from the manganese that is used in welding rods. This is because welding rods contain high concentrations of manganese, which is released in fumes during the welding process, and the welders breathe it in.

Unlike ingested manganese, inhaled manganese is much more toxic because it is transported directly to the brain before it can be metabolized by the liver. (1)

Although it is not common, you can also get manganese toxicity from drinking water that is contaminated by high levels of manganese. For example, 25 people who drank water contaminated with manganese reported severe neurological symptoms. (1)

Therefore, if you are around manganese pollution, you can indeed have resulting hearing problems. However, if this is not the case, and you are not taking more than 5 mg of dietary manganese supplements a day, your chances of getting hearing loss and the accompanying tinnitus are virtually non-existent.

Thus, unless you have noticed a hearing loss since you began taking supplements with manganese in them, I think you can assume that your tinnitus is not caused by manganese toxicity.

If you want to look up the ototoxic side effects of manganese and other ototoxic chemicals (or any ototoxic drugs or herbals), see my book “Ototoxic Drugs Exposed” 3rd edition. This book contains information on the ototoxicity of 877 drugs, 35 herbs and 148 chemicals.
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(1) Manganese. 2001-10. Linus Pauling Institute, Oregon State University.

(2) The Complete Book of vitamins and Minerals for Health. 1988. Rodale Press. Emmaus, PA. p. 643.

(3) Faelten, Sharon. 1981. The Complete Book of Minerals for Health. Rodale Press. Emmaus, PA. p. 130.

(4) Ding, D. 2011. Manganese is toxic to spiral ganglion neurons and hair cells in vitro. Abstract and full article.

(5) Hughes, Martin. 2011. Supplements for Tinnitus.

(6) Nature’s Sunshine Products NSP. 2006. Ear – Ringing (Tinnitus). http://nspforum.com/viewtopic.php?t=745

(7) $2 Million Funds Study on Hearing Loss from Manganese, Noise. 2013.

(8) Bauman, Neil. 2010. Ototoxic Drugs Exposed. Integrity First Publications. Stewartstown, PA.