Summary:
In this Q&A, Dr Sharon Curhan discusses a new study that highlights a link between seafood intake and a reduced risk of developing chronic tinnitus, suggesting diet as a potential factor in auditory health.
Key Takeaways:
- Diet and Tinnitus Risk: Regular seafood consumption, particularly tuna, light-meat fish, and shellfish, was associated with a lower risk of developing persistent tinnitus.
- Type of Seafood Matters: While light-meat fish and shellfish reduced tinnitus risk, consuming dark-meat fish and fish oil supplements was linked to a potentially higher risk.
- Preventive Insight for Clinicians: Findings suggest audiologists and health professionals consider diet in patient discussions to support overall auditory and age-related health.
The Hearing Review sat down with Sharon Curhan, MD, ScM, physician and epidemiologist at Brigham and Women’s Hospital and Harvard Medical School in Boston, Mass., to discuss new study findings published by The American Journal of Clinical Nutrition showing a link between seafood intake and risk of developing chronic tinnitus.
There have been previous studies on the effects of diet on hearing loss and tinnitus. What makes this study different?
Few previous studies have had the ability to evaluate longitudinal relations of dietary intake and risk of incident tinnitusin a large well-characterized cohort of participants (>73,000 women) who have been followed for decades with updated and highly detailed information on dietary intake, tinnitus and on a wide range of potentially associated factors. The rich data resource of the NHS2 enabled us to examine the independent longitudinal association of seafood intake and the risk of developing tinnitus, while adjusting for a wide range of potential confounders. We also had the ability to examine specific types of seafood and fish oil supplement use.
In your research, you found that some types of seafood had a positive effect on tinnitus risk. Can you elaborate on those findings, and the amounts consumed?
We observed a lower risk of developing incident persistent tinnitus among participants who consumed seafood regularly. Notably, we found a linear, direct association between the number of servings of total seafood consumed per week and the risk of incident tinnitus.
Further Reading: Frequent Use of OTC Analgesics Associated with Tinnitus
It was interesting that the magnitude of the association depended on how often and what type of seafood was consumed. Regularly eating tuna fish, light-meat fish and shellfish were each associated with lower risk, while there was a suggestion that eating dark-meat fish was associated with higher risk.
Specifically, compared with participants who never or rarely consumed seafood, the risk of developing persistent tinnitus was approximately 13% lower among those who ate 1 serving of seafood per week and 20-23% lower among those who ate 2 or more servings of seafood per week.
For the specific seafood types: compared with participants who never or rarely consumed the specific seafood type, the risk of developing persistent tinnitus was 16% lower among those who ate one or more servings of canned tuna fish per week; 10% lower among those who ate one or more servings of light-meat fish; and 18% lower among those who ate one or more servings of shellfish per week.
To give you a sense of the quantities consumed, servings of the individual seafoods were defined as follows: One serving of canned tuna fish (3-4 ounces); one serving of dark-meat fish, such as tuna steak, mackerel, salmon, sardines, bluefish, swordfish (3–5 ounces.); one serving of light-meat (other) fish, such as cod, haddock, halibut (3–5 ounces); one serving of shellfish, such as shrimp, lobster, scallops, clams as a main dish.
What seafood was shown to have a negative effect on tinnitus risk in the study, and what conclusions can be drawn about this?
A higher risk among those who consumed dark-meat fish such as tuna steak, mackerel, salmon, sardines, bluefish, swordfish was suggested.
Notably, fish oil supplement use was associated with a 12% higher risk of developing persistent tinnitus.
It’s worth noting that fish oil supplements are not Food and Drug Administration (FDA) approved as over-the-counter medications and have no FDA approved clinical indications. In contrast to the rigorous regulatory standards for safety, efficacy, and manufacturing of prescription and over-the-counter medications, dietary supplements such as fish oil are classified as food by the FDA.
There are several concerns regarding non-prescription fish oil supplements, including demonstrated variability in content, inconsistencies in labeling, low product quality, impurities, and contaminants (that may be neurotoxic or ototoxic). There can also be substantial heterogeneity in the doses of individual OTC omega-3 fatty acids in available supplements, so the variability in the safety and efficacy between specific brands of supplements is unknown.
Further studies that evaluate fish oil supplements with known content and quality are needed.
Are there any recommendations that could be made about how to change a person’s diet to decrease tinnitus risk, and can it make a difference if they already have tinnitus?
Fish and shellfish are recognized as important contributors to an overall healthy diet. They are the major sources of long-chain omega-3 polyunsaturated fatty acids (PUFAs) and are rich in vitamin D, several B vitamins, folic acid, and minerals such as selenium, iron, zinc, iodine, magnesium, and potassium, high in protein and low in saturated fat. Our previous research showed that eating seafood was associated with a lower risk of developing hearing loss. Other previous studies show the benefits of eating fish once or twice a week, including reduced risk of cardiovascular disease, depression, neurodegenerative disease, and other chronic conditions.
Whileclinical recommendations regarding fish oil supplements are beyond the scope of this study, I would encourage individuals to consult with their healthcare provide to discuss the risks and benefits of fish oil supplement use keeping in mind the quality concerns I previously mentioned. Although this study did not examine whether seafood intake could help alleviate tinnitus symptoms among those with persistent tinnitus, we currently have a research study in progress that investigates this question.
Participants in this study were all women. Why is that, and how do you think this affected the results?
Studies that focus on women address an unfortunate research gap. Our study was conducted in the large ongoing Nurses’ Health Study 2 (NHS2) cohort and our participants are all females. We focused on the NHS2 because it provides a singular and unique opportunity to take advantage of a wealth of multidimensional information, including extensive and detailed longitudinal data on health, diet, lifestyle, and tinnitus-related factors, as well as biospecimens that allow us to comprehensively evaluate how metabolism (studying the metabolome), genetics, and microbiome influence the risk of tinnitus and other hearing disorders.
Additional studies in men and in other populations could be informative; however, we suspect that the association between seafood consumption and risk of tinnitus may be similar among men.
How can hearing care professionals use this information to talk to their patients about tinnitus risk?
Our hope is to increase the recognition that hearing health is multidimensional and a critical component of healthy aging. At the same time, healthy aging is an important contributor to hearing health. There’s an ever-growing body of evidence supporting the major principles behind healthy eating and the tremendous benefits to health, longevity, vitality, and quality of life that a healthy diet can provide. Teamed with keeping weight in a healthy range, exercising regularly, and not smoking, eating well can prevent heart attacks, type 2 diabetes, stroke, memory loss, and other neurodegenerative conditions.
As mentioned above, fish and shellfish are recognized as important contributors to an overall healthy diet. Our findings suggest that a diet that regularly includes seafood intake, particularly tuna fish, white-meat fish, and shellfish, may also help reduce the risk of developing tinnitus.
Is there anything else you’d like to share about this study and any hopes you have for how the information might be used?
Our CHEARS research focuses on hearing and health and living well across the lifespan, thus the key place to start is with prevention. Can we prevent or treat persistent tinnitus? Can we better understand the underlying biology and pathophysiology and identify factors that can modified to influence the course? To address these questions, our research team is using innovative approaches to identify modifiable risk factors for tinnitus, better understand the pathogenic changes, provide insights into the classification of subtypes, and identify potential prevention strategies and treatment targets.
How can we think about and provide care for those with tinnitus in a more integrative and comprehensive way? Our research highlights how audiologists can integrate considerations about diet and nutrition to better understand their influence on auditory health. Our hope is to increase the recognition that auditory health is multidimensional and a critical component of healthy aging. At the same time, healthy aging is an important contributor to auditory health. What’s more, auditory health could offer helpful insights into other research in chronic disease prevention.
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