Higher intake of iron and zinc linked to lower tinnitus risk – Australia study

Tinnitus is characterised by a phantom perception of sound, such as ringing or buzzing, in the ears or head that can be constant or intermittent.

As ageing populations worldwide continue to grow, tinnitus prevalence is expected to increase, and solutions are needed to reduce the burden of its symptoms.

Despite rising interest in the role of nutrition in the development and management of tinnitus, there remains a lack of longitudinal evidence on the association between dietary intake of vitamins and minerals and tinnitus in ageing adults.

To address this knowledge gap, a study was conducted to explore the link between these essential nutrients and the 10-year incidence of tinnitus among a cohort of Australians aged 50 years and older.

The baseline population comprised 2,947 participants from the Blue Mountains Eye and Hearing Study II (1997-1999) supported by Australia’s National Health and Medical Research Council.

Among these participants, 935 (31.7%) presented with tinnitus and were included in prevalence analyses. Out of the remaining 2,012 people, 1,109 (55%) had 10-year follow-up data.

A food frequency questionnaire was used to calculate the self-reported intake of dietary vitamins and minerals across 145 food items.

The vitamins and minerals assessed were namely alpha-carotene, beta-carotene, beta-cryptoxanthin, combined lutein and zeaxanthin, lycopene, vitamins A, C, and E, iron, and zinc.

Although no meaningful associations were found between tinnitus prevalence and iron and zinc, some significance with incident tinnitus was observed with higher intake.

Incident tinnitus refers to noise-induced hearing loss caused by a single incident, such as an explosion or close-range gunshot.

Analyses of the 10-year data showed that lower iron intake of ≤9.51mg/d significantly increased the risk of incident tinnitus by 35%, compared to higher iron intake of >9.51mg/d.

Similarly, lower intake of zinc (≤8.48mg/d) versus intake of greater than 8.48mg/d significantly increased the risk of incident tinnitus by 44%.

“Given that ours is an observational study, we can only posit potential underlying mechanisms for this link. One potential mechanism is that zinc is involved in the cochlear pathology and the synapses of the auditory system. ​

“As zinc plays a key role in various cellular processes and pathways, and has antioxidant and anti-inflammatory properties, lower intake of zinc may increase the susceptibility of the auditory system to the effects of inflammation,” ​the researchers wrote.

This is based on findings from a recent systematic review, which suggested that inflammation of the auditory pathway could result in neuroplasticity (changes in brain activity in response to intrinsic or extrinsic stimuli) that causes chronic tinnitus.

“Our present study is the first longitudinal study to report that low dietary intake of iron and zinc can potentially increase the risk of developing tinnitus over 10 years in older adults. However, our findings do not suggest a causal relationship and therefore, conclusions should be drawn with caution. ​

“Future research efforts should include robust study designs, such as large cohort studies and randomised controlled trials,​ to confirm our findings and draw representative conclusions on the link between food-based sources of these nutrients and tinnitus risk.”​

Barrier to healthy ageing​

Tinnitus reportedly has a global prevalence of 14.4% in all adults, and 23.6% in older adults.

Severe tinnitus can debilitate quality of life, leading to poor sleep, difficulty sustaining attention, feelings of frustration, anxiety, and depression.

Existing treatment options are mainly centred on the relief and management of symptoms. These include pharmacotherapy, counselling, cognitive behavioural therapy, and sound therapy.

A potential pathway of tinnitus is inflammation of the auditory system.

As age is a considerable predictor of both inflammation and tinnitus, strategies to promote healthy ageing, including diet, have been suggested as potential preventative solutions or alternative treatment options.  

Vitamins and minerals are essential for health due to their role in various metabolic pathways, as well as their antioxidant and anti-inflammatory properties.

“Based on current evidence, tinnitus is not linked to a nutrient deficiency. Food or dietary pattern-related research may lead to a better understanding of the influence of iron and zinc in tinnitus, especially since our study has identified significant associations.​

“This approach is needed as single-nutrient solutions (supplements) are generally linked to relative deficiencies — for example, deficiencies arising from restrictions of certain foods or food groups, such as veganism, or due to physiological changes like pregnancy,” ​the researchers concluded.

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Source: Nutrients

https://doi.org/10.3390/nu16152535​

“The Association between Dietary Intakes of Vitamins and Minerals with Tinnitus”​

Authors: Diana Tang, et al