Role of Multiple Antioxidant Micronutrients in the Prevention and Management of Meniere s Disease.

Transcription

1 Role of Multiple Antioxidant Micronutrients in the Prevention and Management of Meniere s Disease. Kedar N. Prasad, Ph.D. William C. Cole, Ph.D. and Gerald M. Haase, M.D. Premier Micronutrient Corporation, Antioxidant Research Institute, Novato CA Please send all correspondence to: Kedar N. Prasad, Ph.D. Chief Scientific Officer Premier Micronutrient Corporation 14 Galli Drive, Suite 200 Novato CA 949

2 Meniere s disease (MD) is a disorder of the inner ear that can cause episodes of vertigo (the abnormal sensation of movement), dizziness, ringing in the ears (tinnitus), fluctuating and progressive hearing loss, balance, and a feeling of fullness or pressure. In addition to hearing loss, sounds may appear distorted with some patients experiencing unusual sensitivity to noises (hyperacusis). These changes can occur in one or both ears. This disease is named after a French physician Prosper Meniere who first described this inner ear disorder in It has been estimated that about 2% of the US population may have MD, but others have reported only 0.2%. The majority of people with MD are over the age of 40 years of age. Men and women are equally affected by this disease. A typical attack of MD is often preceded by fullness in one ear, hearing fluctuation or changes in tinnitus. MD episodes generally involve severe vertigo, imbalance, nausea and vomiting. The average attack may last 2-4 hours after which most people feel exhausted and must sleep for several hours. Another disabling consequence is a sudden fall that may occur without warning, and can result in severe injury. Other symptoms may include socalled brain fog (temporary loss short- term memory, forgetfulness, and confusion), exhaustion and drowsiness, headaches, vision problems, and depression. Some of these symptoms are also common to other chronic diseases. Several Meniere attacks may occur within a short period of time. In some cases, years may pass before another attack of MD occurs. Between the acute episodes, most people may be free of symptoms, but some may experience mild imbalance and tinnitus. Meniere s disease usually starts in one ear and over time (usually within 5 years) both ears are affected with this disease. In most cases progressive hearing loss occurs in the affected ears. MD causes death of Cochlear (hearing) hair cells, and it also gradually damages vestibular (motion sensing) hair cells. The fluid filled hearing and balance membranous structures of the inner ear normally function independent of other fluid systems in the body, and the volume of the fluid (known as endolymph) remains constant. However, this changes with the injury or degeneration of the inner ear structures. One of the established pathological features

3 includes fluctuating pressure of the fluid within the inner ear, referred to as endolymphatic hydrops or excess fluid in the inner ear. The membranous structure in the inner ear called labyrinth contains endolymph. This structure can become dilated like a balloon when pressure increases due to either blockage of the drainage system or entry of excess amounts of fluid. It is believed that endolymphatic fluid bursts from its normal channel in the ear and flows into other areas causing damage to the auditory and vestibular systems. The exact causes of MD are unknown. However, some of the agents that can induce MD include family history, middle ear infection, head trauma, upper respiratory tract infection, consumption of aspirin, smoking cigarettes or drinking alcohol. The symptoms of MD can be further aggravated by excessive consumption of caffeine and salt in some cases. The current treatment of MD includes medication, surgery and diet. Medications commonly used for acute episodes are Meclizine (Antivert), Lorazepam (Ativan), Phenergan, Compazine, Dexamethasone (Decadron) and calcium channel blockers.. Medication used between attacks include diuretics, dyazide (Triamterine/HCTZ). Steroids and immune suppressants are rarely used. Surgical treatment is the last resort in severe cases of MD. Dietary recommendations include food and adequate fluid intake evenly throughout the day, reduced intake of salt and sugar, avoidance of caffeine and foods containing monosodium glutamate, and limited alcohol consumption. These treatment methodologies have been useful to manage the symptoms of the disease, but have failed to prevent the progressive damage to cochlear and vestibular hair cells. To address this problem it is essential to understand the mechanisms that are involved in the death of these cells. The exact mechanisms of damage to Cochlear (hearing) hair cells and vestibular (motion sensing) hair cells in MD are unknown. However, recent studies suggest that increased oxidative stress (due to generation of excessive amounts of free radicals) and uncontrolled chronic inflammation may contribute to the death of hair cells. The involvement of free radicals in the mechanism of damage of hair cells is supported by the

4 fact that administration of certain antioxidants improves symptoms of vertigo and tinnitus in some patients with MD. Noise and vibration also cause death of hair cells in animals and humans and induce tinnitus and hearing loss. This has been shown to be prevented by certain antioxidants in both animal and human studies. It has been suggested that repeated inflammatory reactions can damage the endolymphatic sac, eventually leading to MD. The presence of certain antigens in the blood of patients with MD, but not in the blood of normal subjects suggests the involvement of inflammation in this disease. In addition, the tissue damage occurs following exposure to one or more MD-inducing agents, and this can initiate uncontrolled inflammation. Antioxidants are known to neutralize free radicals and reduce inflammation; therefore, they should be very useful in reducing the death of cochlear and vestibular hair cells in patients with MD. This approach may enhance the efficacy of the current treatment strategies for the management of MD. Two previous studies have utilized one or more antioxidants in treating MD. This approach may not be adequate. The use of both dietary and endogenous antioxidants is essential for increasing the effectiveness of an antioxidant approach. Our preliminary study in collaboration with US Navy physicians has revealed that multiple antioxidant micronutrients in combination with standard therapy improved the balance and hearing loss in veterans with mild traumatic brain injury more than that produced by standard therapy alone. For an optimal effect from antioxidant micronutrients, the doses of ingredients as well as dose schedule is very important. Doses are very important because at certain doses, antioxidants will reduce free radicals but may not decrease inflammation. Taking antioxidants once a day may not be adequate, because of great fluctuations of antioxidant levels in the body. For example, if a person takes vitamins in the morning, half are eliminated from the body by the evening, and another half by the next morning. The genetic machinery of the cell constantly has to re-adjust to cope with such a huge variation in antioxidant levels, and this could create cellular stress. Any formulation containing iron or copper is not recommended, because they combine with vitamin C and generate excessive amounts of free radicals. The addition of heavy metals such as molybdenum, zirconium, and vanadium is also not recommended, because nature has provided no significant mechanisms of removal of these heavy metals from the body. An

5 accumulation of these metals after long-term consumption could be toxic to nervous tissue including the brain. For prevention, antioxidant micronutrients can be taken after the first episode of MD. It is hoped that the proposed strategy with antioxidant micronutrients may prevent the progression of damage in the inner ear hair cells. For those who are suffering from MD and are on standard medication, daily supplementation with antioxidant micronutrient may enhance the efficacy of the treatment, and reduce the progression of the disease. For further information, the Ear Foundation of Nashville can be contacted.