Hearing Loss and Nutrition

The importance of nutrition for good health continues to pop up in unexpected places. Hearing loss affects more than 28 million Americans, and is one of the four most prevalent chronic conditions in the elderly. Forty percent of those 75 years old and older, community dwelling elders suffer some degree of loss. The biological basis of this late-life hearing loss is unknown.

While some research on hearing and nutrition is very new, some studies go back as far as the 1930's and 1940's. In 1989, Hughes suggested that diet, especially several micronutrients, could be involved in the development of many age-related hearing disorders in humans and animals. Low levels of vitamins mentioned in the literature include vitamins A, B complex, C, D, and E.

A couple of new studies focus on calcium and vitamins B-12 and folate. In the calcium study conducted at the University of Georgia and the Centers for Disease Control, seventy women ages 60 to 71 with impaired hearing were found to have 11 percent lower spinal bone density and 25 to 30 percent lower calcium intake than their same-age counterparts with normal hearing. Recent studies also implicate iron deficiency.

The new Houston study in the American Journal of Clinical Nutrition examined inadequate vitamin B-12 and folate nutriture and auditory loss in women 60-71 years old. These two vitamins are particularly suspect because they are two of the most common vitamin inadequacies in the elderly. B-12 deficiency is estimated to be 5 to 15 percent of the elderly population and folate deficiency is present in 2 to 20 percent. These deficiencies could effect both the nervous and the vascular system associated with hearing. For example, a high homocysteine blood concentration from inadequate B-12 and folate could interfere with the blood flow to the inner ear. Low vitamin B-12 may also inhibit myelination (the outer covering) of the neurons in the cochlear nerve. In this research, low concentrations of serum vitamin B-12 and red cell folate were associated with hearing loss. However, it is well to remember that there was only a small number of subjects in this study and the women had relatively mild hearing loss. Of course, more research is needed.

The moral of the story is that as nutrition research accumulates over the coming years, it appears obvious that poor nutrition will be associated with many symptoms commonly assumed to be part of "natural aging" but that are really not aging at all. The basis of any sound nutrition program should emphasize the importance of variety and the consumption of relatively unprocessed foods like fruits and vegetables and whole grains.

Sources: Houston, DK, MA Johnson, RJ Nozza, EW Gunter, KJ Shea, GM Cutler, JT Edmonds. 1999. Age-Related hearing loss, vitamin B-12, and folate in elderly women. Amer J Clin Nutr. 69: 564-71. Hughes, G. 1989. Molecular and cellular biology of the inner ear: the next frontier. Am. J. Otol. 10:28-35. Women with hearing loss may benefit by boning up on calcium. Environmental Nutr. Oct. 1998. P, 8.

Mary P. Clarke, Ph.D.
Extension Specialist, Nutrition Education

5/99 FILE: NUTRITION, NORMAL/General

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