A new study suggests that a person's diet can have a substantial impact on his or her levels of tinnitus and/or hearing loss. Researchers from the University of Manchester analyzed cross-section associations between tinnitus, hearing difficulties, nutrient intakes, and dietary patterns using a questionnaire that was repeatedly administered over the course of a year. They found that diets low in fat and high in vitamins and antioxidants may be vital for better hearing health.
The study, titled “Relationship Between Diet, Tinnitus, and Hearing Difficulties”, also identifies prior evidence that both hearing loss and tinnitus may be associated with lifestyle factors such as noise exposure, smoking, alcohol consumption, exercise, and diet. This evidence offers possibilities for hearing loss prevention.
“There is accumulating evidence that diet affects susceptibility to hearing loss and tinnitus,” said Piers Dawes, BSc, DPhil, the first author of the study. “Prevention of hearing problems is obviously extremely desirable, and a healthy diet may offer one opportunity for prevention. A nice feature of our analysis was that we examined how dietary patterns (rather than just levels of single nutrients) relate to hearing health, so reflecting actual diets within the population.”
To analyze the association between hearing loss, tinnitus, and diet, the researchers used the U.K. Biobank, an international resource for health research that contains data from over 500,000 adults in the United Kingdom ages 40 to 69 years at the time of their assessment. Although the U.K. Biobank sample isn't representative of the country's general population, it is figured to be generalizable because of the size of the sample. As of 2014, 16.9 percent of U.K. adults between 40 to 69 years old had tinnitus. Hearing impairment is more common among the older U.K. population, affecting 36.7 percent of adults aged 61 to 70 years.
The recruited study participants reported that they had hearing loss. Tinnitus was based on their report of ringing or buzzing in one or both ears that lasted more than five minutes at a time and was experienced at least some of the time.
The participants completed a 90-minute assessment that included a computerized questionnaire on their general health, medical history, lifestyle, environment, and details of their hearing loss. To assess the participants’ diet, the Oxford Web-Q 24-hour dietary recall questionnaire was administered. This questionnaire asked participants about their intake of 200 commonly consumed food and beverages within the past 24 hours along with each portion size. Participants were invited to take the Web-Q questionnaire at least two times, which was used to calculate their dietary intakes. Both raw nutrient and nutrient intakes were also adjusted based on an individual's energy levels, then later analyzed by the researchers.
“We had a unique opportunity to analyze very high-quality data about diet for a very large group (35,576) of adults with respect to tinnitus and hearing problems,” said Dawes. “But the scientific challenges were significant; we first had to analyze an enormous amount of dietary intake data to estimate each person's intake of micro- and macronutrients. We then had to analyze these intake estimates to the highest standards of dietary epidemiology. This is critical because analyses of dietary factors are particularly susceptible to confound with other lifestyle factors that may impact hearing.”
Along with their diet and history of hearing loss, participants who had cardiovascular disease and high cholesterol were identified so the data may be adjusted accordingly. The same identification procedure was used for participants who were taking diabetic or blood pressure medication. The body max index (BMI) was calculated using the participants’ weight and height as well. Data on each participant's sex, race, and area of residence were also recorded. These data were translated to Townsend deprivation scores, which are based on employment, non-car ownership, non-home ownership, and household overcrowding.
In total, 47,072 participants completed at least two rounds of the questionnaire on their lifestyle, diet, and hearing. The analysis suggested that a higher intake of vitamin B12 and protein was associated with reduced odds of tinnitus, which aligns with the results of previous studies by the same research group. Typically, meat, fish, and poultry are a patient's primary sources of vitamin B12. The study also noted similar findings in a recent Korean population study in which the researchers reported that lower intakes of protein, vitamin B2, and vitamin B3 were linked to increased tinnitus.
On the contrary, high intakes of calcium, iron, and fat were associated with increased odds of tinnitus. High intakes of saturated fat have been previously linked to hearing loss possibly by cardiovascular disease pathways. The abnormalities in the calcium signaling pathway in outer hair cells have also been previously linked to tinnitus, and calcium channel blockers have been investigated as a treatment for tinnitus. More importantly, diets high in fruits, vegetables, and unprocessed meat and low in animal fat were linked to reduced likelihood of hearing difficulties. In contrast with past studies that have suggested that sugary, high glycemic index nutrition may be associated with poorer hearing, carbohydrate and sugar intake were not related to hearing in this study.
“The findings suggest that a healthy diet may help prevent hearing problems,” Dawes said. “The dietary associations suggest a very large impact of diet on levels of tinnitus and hearing difficulties in the general population because of the universal nature of the exposure—because everyone eats!”
The study also points out that although there is some evidence that certain foods, single nutrients, and dietary supplements reduce or aggravate tinnitus in patients, there is little to no evidence for the role that certain dietary factors play in causing tinnitus. In fact, the particular research associated with vitamin B12, B3, and zinc deficiency and the effects of supplementation and tinnitus is inconsistent.
Previous research on the association between diet and hearing loss focused on analyzing single nutrients. One drawback of this kind of study is that examining a wide range of single nutrients increases the likelihood of false-positive associations. However, some general conclusions from these studies may be possible, such as a higher intake of lipids, carbohydrates, and sugar is typically associated with poorer hearing while polyunsaturated fats are associated with better hearing. The inconsistent variables and results from single nutrient analysis led the researchers to consider a dietary analysis plan for this study.
Although this study has a wide range of new information and is the first that the researchers are aware of to suggest an association between levels of dietary B12 and tinnitus, it also had its own limitations. The study authors noted that “it was not possible to establish casual associations based on the cross-sectional correlational design on the present study or to examine the time course of exposure to dietary factors and development of hearing difficulties/tinnitus.” Furthermore, the higher intake of iron associated with increased odds of tinnitus seems contradictory to the findings of a high-protein diet being linked to lower odds of tinnitus since meat, fish, and poultry are sources of iron. Despite this, the study has been consistent with the findings of past dietary analyses showing that healthy diets can promote overall good hearing health.
With these findings, the researchers hope to study the impact that a patient's diet has on tinnitus and hearing difficulties and later discover a way that audiologists can predict these difficulties within the population.
“The analysis was cross-sectional, so a logical next step would be to test whether dietary factors predict development of tinnitus and hearing problems in a longitudinal study,” said Dawes.