Unprecedented studies reveal a link between higher intake of fish and reduced risk of hearing loss
By Craig Weatherby
Listen up… medical science just added ears to the list of organs that may benefit from diets rich in fish or their omega-3-rich oils.
That list includes all of the major human organs… heart, arteries, brain, eyes, liver, lungs, kidneys, and skin… plus joints.
But unlike joints and most organs, there hasn’t been much research on omega-3s and hearing health.
Hearing loss is the most common sensory disorder in the United States, affecting about 36 million (one in 10) Americans.
About one in three adults between 65 and 75 suffer aging-related hearing loss—which is usually greater for high-pitched sounds—and almost half of people 75 and older experience substantial hearing loss (NIDOCD 2010).
So research into the auditory effects of omega-3s seems overdue… and the positive findings obtained from two epidemiological (population) studies should prompt even more research.
Dutch study links omega-3 blood levels to hearing health
Holland is a coastal nation with a long history of fishing and eating fish… which may explain why scientists from its Wageningen University have held some of the largest clinical trials testing fish oil for heart, mood, and brain health.
Members of the teams that performed those trials turned their attention to hearing, and conducted a three-year study to look for links between people’s omega-3 blood levels and their hearing health.
The Dutch team recruited 720 men and women aged 50-70 years, none of whom had problems with hearing at the start of the study (Dullemeijer C et al. 2010).
They tested the participants’ omega-3 levels and hearing at the beginning and end of the three-year study, looking for changes in their ability to hear sounds that fall in various frequency ranges… that is, low tones like a bullfrog’s call, and high tones such as birds chirping.
After three years, the volunteers who had the highest omega-3 blood levels showed less hearing loss in lower frequency ranges.
However, there were no significant links between omega-3 levels and hearing loss in the high frequencies.
Coming from an epidemiological study rather than a well-designed clinical trial, these results can suggest but not prove a cause-effect relationship between higher omega-3 intake and less hearing loss.
As the Dutch crew wrote, “These results are encouraging, but require confirmation from future studies” (Dullemeijer C et al. 2010).
Aussie study points to possible hearing protection from omega-3s
Among other reports on omega-3s and vision health, readers of Vital Choices may remember our summaries of research from Australia’s Blue Mountains Eye Study.
(See “Omega-3s Linked to Eye Health… Again” and “Fish Seen Helping in Fight to Save Sight.”)
Now, the Blue Mountains study team
—led by Professor Paul Mitchell, M.D., Ph.D.
—just published the results of a similar epidemiological study, called the Blue Mountains Hearing Study.
The Sydney team analyzed diet and hearing health data collected from 2,956 participants.
The volunteers’ intakes of fish-borne omega-3s were estimated using diet surveys, and they were given hearing tests.
The results of the Aussie team’s analysis linked higher omega-3 intakes to a reduced risk of aging-related hearing loss, while linking higher omega-3 intakes to a reduced risk.
Compared with the participants who reported eating less than one serving of fish per week, those who said they ate two or more servings per week were 42 percent less likely to have aging-related hearing loss.
The Blue Mountain team made the obvious observation: “Dietary intervention with [omega-3s] could prevent or delay the development of age-related hearing loss” (Gopinath B et al. 2010).
Again, as we said about the Dutch study, statistical correlations like these cannot prove that fish oil prevents hearing loss, so clinical trials are needed.
- Dullemeijer C, Verhoef P, Brouwer IA, Kok FJ, Brummer RJ, Durga J. Plasma very long-chain N-3 polyunsaturated fatty acids and age-related hearing loss in older adults. J Nutr Health Aging. 2010;14(5):347-51.
- Gopinath B, Flood VM, Rochtchina E, McMahon CM, Mitchell P. Consumption of omega-3 fatty acids and fish and risk of age-related hearing loss. Am J Clin Nutr. 2010 Jun 9. [Epub ahead of print]
- National Institute on Deafness and Other Communication Disorders (NIDOCD). Presbycusis. Accessed at http://www.nidcd.nih.gov/health/hearing/presbycusis.asp