At least two servings of fish per week was associated with a 42 per cent reduction in the risk of hearing loss in over 50 year-olds, compared with people who average less than one serving per week, according to findings published in the American Journal of Clinical Nutrition.
Similar reductions were observed with intakes of long-chain omega-3 fatty acids, with increasing intakes associated with 14 per cent reductions in the risk of age-related hearing loss (presbycusis).
“Dietary intervention with omega-3 polyunsaturated fatty acids could prevent or delay the development of age-related hearing loss,” wrote the researches, led by Paul Mitchell.
Hearing loss is the most common sensory disorder in the United States, affecting more than 36 million people.
Beyond omega-3
Other micronutrients have been linked to reducing the risk of age-related hearing loss. In 2007 scientists from Wageningen University reported that folic acid supplements delayed age-related hearing loss in the low frequency region in a study of 728 men and women between the ages of 50 and 70 (Annals of Internal Medicine, Vol. 146, pp. 1-9).
Another study, published earlier this year indicated a role for beta carotene and vitamins C and E, and the mineral magnesium in preventing prevent both temporary and permanent hearing loss in guinea pigs and mice. The animal study was presented at the Association for Research in Otolaryngology's annual conference in Baltimore in February 2009.
Fish: Food for hearing
Mitchell and his co-workers analysed data from 2,956 participants of the Blue Mountains Hearing Study. Dietary intakes of fish, and the omega-3s they contain, using food-frequency questionnaires.
Results showed an inverse association between total and long-chain omega-3 intakes and hearing loss, while increasing fish intakes also indicated a reduction in the risk of presbycusis, said the researchers.
Correlation is not causation, however, and significant further research is needed, including human intervention trials.
Listening to the market
Omega-3 is one of the stars of the nutrition industry, with the ingredients market valued at a whopping $1.6 billion by Frost & Sullivan. The fatty acids, most notably EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), have been linked to a wide-range of health benefits, including reduced risk of cardiovascular disease (CVD) and certain cancers, good development of a baby during pregnancy, joint health, and improved behaviour and mood.
Source: American Journal of Clinical Nutrition
Published online ahead of print, doi: 10.3945/ajcn.2010.29370
“Consumption of omega-3 fatty acids and fish and risk of age-related hearing loss”
Authors: B. Gopinath, V.M. Flood, E. Rochtchina, C.M. McMahon, P. Mitchell