Docosahexaenoic acid (DHA) was particularly associated with a lower risk: individuals with the highest DHA intakes were 8 to 20% less likely to report hearing problems, according to a population-based, cross-sectional study.
Presenting author Dr Michael McBurney, senior scientist at the Fatty Acid Research Institute in Ontario, told Vitafoods Insights: “There is evidence from animal models that omega-3 fatty acids, including DHA and eicosapentaenoic acid (EPA), play a role in the development of the auditory system and cochlear function and maintenance.”
Higher DHA levels linked with lower risk of hearing loss
To evaluate the association between plasma omega-3 fatty acids and self-reported hearing loss, the researchers used the UK Biobank, which collected data from questionnaires, biological samples, and physical measurements for more than 500,000 40- to 69-year-olds between 2007 and 2010.
Thirty-eight percent of 115,303 eligible respondents reported difficulty hearing, 26% of 113,134 reported background noise hearing problems, and 5% of 71,368 respondents used hearing aids.
An inverse relationship between omega-3 plasma levels and self-reported hearing loss was reported. People with the highest DHA levels had a lower risk relative to those with the lowest levels, with individuals in the top DHA quintile 8 to 20% less likely to report hearing loss.
Asked what makes DHA different to other fatty acids, McBurney said: “Our bodies can transform alpha-linolenic acid (ALA) to EPA, and then to DHA, but we are not very efficient.
“Although foods contain ALA and fatty fish are a source of EPA and DHA, the availability of optimal amounts of DHA to all cells, including the brain, eye, and cochlea, may be limiting.
“Thus, dietary intake [of] DHA is important. The solution is to ingest EPA and DHA, with fatty fish and omega-3 dietary supplements being important rich sources. EPA and DHA levels are inversely associated with risk for many other diseases and all-cause mortality.”
‘More studies needed’ on how omega-3s affect hearing
As many as 1.57 billion people worldwide experience hearing loss – approximately 20% of the population, World Health Organization statistics show. This figure is expected to increase as the population ages, while low- and middle-income countries bear a disproportionate burden from hearing loss.
Given its prevalence, there is interest in alternative treatment approaches. One study showed that omega-3 polyunsaturated fatty acids may help to prevent age-related hearing loss in mice, thanks to their anti-inflammatory and tissue-protective functions.
Asked where research in the area should focus next, McBurney said: “More animal studies are needed to elucidate mechanisms whereby omega-3 fatty acids affect cochlear function and hearing.
“The highest level of evidence will be obtained in randomised controlled intervention trials (supplement vs placebo) assessing the impact of maintaining higher plasma omega-3 levels on auditory function and related hearing biomarkers in ageing humans.”
He added: “Other cohorts should be explored to confirm the inverse association of plasma DHA with incident hearing loss and the effects of increased DHA intakes on hearing metrics should be tested in randomised trials determining potential causal mechanisms.”
The study was presented today at Nutrition 2023, the annual meeting of the American Society for Nutrition.