Vitamin B12 is a key component of brain and nerve cell metabolism. Deficiencies in the vitamin can cause irreversible damage to the brain and nervous system, with even small deficiencies causing poor memory and depression [[i]].

Some interesting findings were made in an experiment involving 57 military personnel who had been exposed to military noise and were suffering with chronic tinnitus and NIHL. They found that 47% of these subjects had vitamin B12 deficiency which was significantly higher than military personnel exposed to noise but who had normal hearing and no tinnitus. There was improvement in some of the patients following vitamin B12 supplementation, but the results were not conclusive [[ii]].

There is some evidence that supplements of zinc, magnesium and certain vitamins can reduce tinnitus or NIHL. However, a number of these studies have not been conducted against placebo controls and so we cannot confer that they are therapeutically beneficial.