Tinnitus, often described as ringing, buzzing, or whooshing sounds in the ears, is a common condition that affects roughly 10-15% of adults. While tinnitus itself is a symptom and not a disease, it can significantly impact quality of life and lead to anxiety, depression, and sleep problems in some individuals. The underlying causes of tinnitus are not fully understood, but are thought to include hearing loss, ear infections, head or neck injuries, circulatory system disorders, and exposure to loud noises. In recent years, some research has suggested that vitamin D deficiency may also be linked to tinnitus in some patients.
What is vitamin D and what does it do in the body?
Vitamin D is a unique nutrient that functions as a hormone in the body. It plays important roles in absorbing calcium for bone health, modulating immune function, supporting muscle function, and regulating cell growth. The active form of vitamin D (called calcitriol) acts on target cells throughout the body by binding to the vitamin D receptor.
There are two main ways to obtain vitamin D – through skin synthesis from sunlight exposure and from the diet. When skin is exposed to UVB radiation from sunlight, it synthesizes vitamin D3. Dietary sources include fatty fish, fish liver oils, egg yolks, mushrooms, fortified foods like cereal and milk, and supplements.
Once obtained from the skin or diet, vitamin D is metabolized in the liver to 25-hydroxyvitamin D (25(OH)D), the main circulating form used to determine vitamin D status. Kidneys then convert 25(OH)D to the biologically active form calcitriol. Levels of 25(OH)D are used to assess vitamin D status – deficiency is defined as less than 20 ng/mL (50 nmol/L).
How might vitamin D deficiency contribute to tinnitus?
While research is still emerging in this area, some studies suggest vitamin D deficiency may be linked to tinnitus through several potential mechanisms:
Inner ear cell function
Animal studies indicate that vitamin D is important for normal functioning of inner ear hair cells that detect sound and convert it to neural signals. Loss of hair cells is one contributor to tinnitus. Vitamin D deficiency may disrupt metabolism and function in inner ear cells.
Neurological effects
Vitamin D receptors are found throughout the brain and vitamin D is thought to play a role in neurotransmitter synthesis and nerve growth. Deficiency could lead to neural changes that induce tinnitus symptoms.
Inflammation
Some cases of tinnitus may involve inflammatory processes. Vitamin D helps regulate immune system activity and has anti-inflammatory effects. Insufficient vitamin D could allow increased inflammation that exacerbates tinnitus.
Musculoskeletal factors
Tinnitus can sometimes originate due to problems in head, neck, or jaw muscles. As vitamin D supports healthy muscle function, deficiency may promote muscle dysfunction that triggers tinnitus.
What does the research say about vitamin D deficiency and tinnitus?
A number of studies have examined the relationship between vitamin D levels and tinnitus:
Observational studies
Several studies have compared vitamin D levels in groups of people with and without tinnitus:
– A 2016 study of elderly Korean patients found significantly lower serum 25(OH)D levels in patients with tinnitus compared to controls. Over 80% of tinnitus patients were deficient in vitamin D vs. about 60% of controls.
– A 2018 study in Egypt found that adolescents with tinnitus had considerably lower vitamin D levels than healthy adolescents. 65% of tinnitus patients were deficient compared to 30% of controls.
– A 2019 study compared 100 tinnitus patients in Turkey to 100 healthy controls. 72% of tinnitus patients had insufficient vitamin D levels, versus 30% of controls.
Clinical trials
A few small clinical trials have tested effects of vitamin D supplementation:
– A 2015 pilot study had 23 vitamin D deficient patients take high-dose vitamin D (5000 IU/day). After 3 months, researchers observed improved tinnitus scores and quality of life.
– Another study treated elderly tinnitus patients with vitamin D3 (2000 IU/day) or placebo for 4 months. Vitamin D supplementation led to significantly greater reductions in tinnitus severity.
– However, two other clinical trials found no significant improvement from vitamin D supplementation in tinnitus patients.
Limitations
– Studies are relatively small and few in number. Larger randomized controlled trials are still needed.
– It’s possible vitamin D deficiency and tinnitus are linked indirectly, due to association with other medical conditions. More research is needed on potential mechanisms.
– Optimal levels of vitamin D needed to prevent tinnitus are unknown. Effects of long-term supplementation need further study.
Are there risks with excessive vitamin D supplementation?
While moderate doses of vitamin D from foods and supplements are not linked with adverse effects in most people, excessive intake can potentially lead to toxicity. High levels of vitamin D can cause calcium buildup, damage kidneys and the heart.
The recommended daily intake for vitamin D is:
– 600 IU (15 mcg) for most adults
– 800 IU (20 mcg) for older adults
– Maximum limit of 4000 IU (100 mcg) for adults
Taking extremely high amounts like 50,000 IU regularly can put someone at risk of toxicity. Symptoms include nausea, vomiting, poor appetite, constipation, weakness, and frequent urination.
Overall, intakes up to 4000 IU per day are likely safe for the majority of adults. Those with conditions affecting vitamin D metabolism, like chronic kidney or liver disease, should avoid excess intake and have levels monitored by a doctor.
Should people with tinnitus be tested for vitamin D deficiency?
Given the potential connection between vitamin D status and tinnitus, it may be reasonable to assess vitamin D levels in those with new onset or worsening tinnitus complaints.
Testing blood levels of 25(OH)D can help uncover deficiency and determine if supplementation is needed. It’s a relatively inexpensive and accessible blood test.
However, patients should be aware that research has not yet firmly established vitamin D deficiency as a definitive cause of tinnitus. While correcting deficiency may provide some relief in a subset of patients, it is unlikely to resolve tinnitus completely.
Patients should discuss the potential benefits and limitations of testing with their healthcare provider. Those who undergo assessment can ask that the results be shared with their audiologist or ear, nose and throat specialist.
What should you do if your vitamin D is low?
If blood testing does confirm vitamin D deficiency in a tinnitus patient, correcting levels may be one component of treatment. Under a doctor’s care, supplementation with vitamin D3 or D2 is typically used to increase levels.
– Dosages between 2000-6000 IU (50-150 mcg) per day are often used, with monitoring of blood levels.
– Improvement may take 3-4 months as stores are replenished.
– Ongoing maintenance doses may be needed to prevent recurrence of deficiency.
– Dietary sources can help maintain healthy levels after replenishment.
– Reasonable sun exposure can also provide vitamin D, but caution is needed.
While supplementing is generally low risk, excessive intake can lead to hypercalcemia and other problems. Patients should work closely with their healthcare team to find the optimal vitamin D dose for their needs. Routine monitoring of vitamin D levels is also advisable.
What are the best food sources of vitamin D?
While sunshine provides a significant portion of vitamin D for many people, dietary intake also matters for optimizing levels. The best food sources include:
| Food | Vitamin D (IU per serving) |
|---|---|
| Salmon, cooked (3.5 oz) | 360 |
| Herring, pickled (3.5 oz) | 320 |
| Sardines, canned in oil (1.75 oz) | 250 |
| Mushrooms, exposed to UV light (0.5 cup) | 76 |
| Milk, fortified (1 cup) | 120 |
| Yogurt, fortified (6 oz) | 80 |
| Beef liver (3.5 oz) | 55 |
| Egg yolks | 41 |
Aim for foods rich in vitamin D at least a few times per week as part of a balanced diet. Supplements can fill in any gaps needed to reach recommended daily intakes.
Conclusion
Some research indicates vitamin D deficiency may be associated with higher rates of tinnitus in certain groups of people. Proposed mechanisms include effects on inner ear cells, nerve function, inflammation, and muscles. However, the connection is not fully proven and clinical studies testing vitamin D treatment remain limited.
Checking vitamin D levels may be reasonable for those with new onset or worsening tinnitus. Correcting deficiency under medical supervision could offer some relief in a subset of patients. However, vitamin D is unlikely to be a cure-all and should be one piece of an overall treatment approach. More research is still needed to confirm vitamin D’s role in tinnitus.