Positive Health Online

Introduction

Most of us fear getting old. Pain, loss of mobility and the failing of functions like sight and hearing are just some of the reasons. Hearing loss is especially tragic. Imagine not being able to listen to the radio or the stereo, go to concerts or lectures or hear your little grand-daughter sing? Age-related hearing loss, particularly affecting the cochlea of the inner ear, is the leading cause of deafness in the world, with 40% of 75 year-olds affected.

But is the loss of functions an inevitable part of the ageing process? Especially when there is increasing scientific evidence that diet has a big part to play?

Everyone knows that consuming too many chips, crisps, sweets, burgers, biscuits, cakes, sugary drinks and so on encourages nutritional deficiencies and all their associated health problems. This is because they provide a lot of calories in the form of saturated fat and sugar but very few vitamins and minerals. Now we are seeing evidence that these foods can even affect our hearing, and it's not just elderly people who are affected. As we shall see, even children's hearing appears to suffer from a faulty diet.

Definitions of deafness are based on the degree of hearing loss in terms of decibels (dB) ranging from mild to profound hearing loss. A loss of 35 to 70 dB is generally considered hard of hearing, while a loss of 90 dB or greater is considered profoundly deaf. There are two main types of hearing loss.

Conductive Hearing Loss

This is a temporary hearing loss affecting the middle and outer ear, due to an ear infection, wax build-up or other blockage, ruptured ear drum, colds and otosclerosis - abnormalities in the bony labyrinth of the middle ear.

Sensorineural Hearing Loss

This is caused by nerve damage affecting the inner ear and is a permanent hearing loss in about 99.9% of cases. Much of this hearing loss is believed to occur in the cochlea of the ear, which is nourished by many small blood vessels. The damage can be due to:

• Meningitis;
• Maternal rubella;
• Cytomegalovirus;
• Chronic exposure to loud noises;
• Premature birth;
• Head trauma;
• Drug exposure;
• Heredity/genetics and unknown causes.

As we shall see, both types of hearing loss can also have nutritional causes.

The Homocysteine Connection

In a research study carried out at the University of Georgia in 1998, elderly people with impaired hearing were found to have vitamin B12 levels 38% lower and folic acid levels 31% lower than people with normal hearing. These deficiencies inevitably lead to high levels of the toxin homocysteine, which encourages cholesterol deposits to form on artery walls. As we know, such deposits reduce the blood flow and so can also reduce the supply of nutrients and oxygen to the heart and other organs. Parts of the heart muscle or the brain can be destroyed if a small artery becomes completely blocked (occluded), and the ears may suffer from similar harmful effects. B vitamin deficiencies also damage the auditory nerves (those related to hearing).[1]

Saturated Fat and the Microcirculation

A healthy microcirculation - the network of capillaries which supplies every inch of your body tissues - does not just depend on an unrestricted blood flow from your arteries. The red blood cells themselves can also affect your circulation. It is essential that red cells should be 'deformable' - flexible and able to squeeze in single file through tiny narrow capillaries, carrying life-giving oxygen to your brain, inner ear and other tissues. The deformability of red cells depends on their outer membrane, which should incorporate a rich supply of essential (polyunsaturated) fatty acids (EFAs) into its structure. An excess of saturated fat in your diet, especially in the presence of a relative deficiency of EFAs, can interfere with this. Saturated fat is hard fat and when too much is present, it increases blood viscosity and is also incorporated into red cell membranes, making them abnormally hard and inflexible. If these red cells then become stuck in narrow capillaries, 'log-jams' can develop, cutting off parts of the microcirculation. Sensitive cells will be deprived of nourishment and oxygen just as if there was a cholesterol blockage.

In a research study carried out in 1988 on children with hearing difficulties, fluctuations in their hearing were found to vary according to their fat intake. Dietary changes and a drop in cholesterol levels led to a return to near-normal hearing.[2] In another study it was found that hearing impairment at high frequencies was directly related to blood viscosity, red cell rigidity also being an important factor.[8]

Not only deafness but also tinnitus - a continuous ringing in the ears - seems to be linked with a defective microcirculation, and has been treated with the herb Ginkgo biloba. Professor Edzard Ernst of Exeter University says: "if one views tinnitus as being caused partly by impaired microcirculation in the inner ear, the mechanism becomes understandable. Gingko has been shown to improve microcirculatory blood flow by acting on both the vasculature and the blood in a complex fashion. The end result is an improvement of the circulation. This explanation would tie in with its positive effects in other circulatory disorders, e.g. peripheral vascular disease."[3]

A remarkable 82% decrease in blood platelet adhesiveness (which contributes to blood viscosity) has been found after the administration of 400 iu vitamin E to normal volunteers for two weeks.[9]

Nutritional Deficiencies

Nutritional deficiencies may have a profound effect on the hearing ability. Nutrients which have been researched include vitamins A, B12 and D, folic acid, iodine, iron, magnesium and zinc.

Vitamin A

Research is scanty, but vitamin A deficiency appears to cause abnormalities of the otic capsule of the ear, and may also cause atrophy of the cochlea. A number of papers have reported a 5-15 decibel improvement in the pure-tone threshold in patients with hearing loss who are supplemented with a combination of vitamins A and E.[10]

Vitamin B12 and Folic Acid

The University of Georgia study already mentioned found low levels of these B vitamins in elderly people with hearing loss.[1] Cochlear function, say the researchers, is dependent on an adequate vascular supply and normal function of nerve tissue. Homocysteine is elevated during deficiencies of vitamin B12, folate or both, and is believed to be a vascular toxin and a neurotoxin. Poor vitamin B12 and folate status might also adversely affect the central nervous system because of the numerous roles that these nutrients play in cellular metabolism, vascular function and myelin synthesis.

Researchers Shemesh et al at the Institute of Noise Hazards Research in Israel have found that people with chronic tinnitus and noise-induced hearing loss are 2.6 times more likely to be vitamin B12 deficient than those with normal hearing. They suggest that a lack of B12 may cause damage to the protective myelin sheath around nerves in persons subjected to repeated noise exposure. They have managed to obtain some improvement in tinnitus and associated complaints in 12 patients with low vitamin B12 levels following vitamin B12 replacement therapy.[11]

Vitamin D

Otosclerosis, on the other hand, seems to have a strong connection with vitamin D. In one study, abnormally low vitamin D levels were found in 21% of 47 patients with this problem. Supplementation with calcium and vitamin D resulted in significant hearing improvement in three out of 16 cases.[12] The same researchers found that treatment of vitamin D deficiency could prevent progressive hearing loss, and occasionally may partially reverse it.[13]

In some individuals, hearing loss may be a manifestation of vitamin D resistance due to magnesium deficiency - one of the most common nutritional deficiencies found in individuals consuming a western diet. Researchers in Japan have found that 23 out of 28 patients with hearing loss showed a normal value of vitamin D but a significantly decreased level of its biologically active form 1,25-dihydroxyvitamin D3, which is synthesized by means of a magnesium-dependent enzyme.[14]

Iodine

There is both clinical and laboratory evidence that hearing loss can result from congenital and acquired hypothyroidism. Both iodine and iron play major roles in thyroid hormone metabolism, and deficiencies of both minerals have been investigated for their role in hearing loss. French research suggests that iodine deficiency is a major public health problem in several European countries. It has found that hearing impairment at speech frequencies is more severe among children at risk of mild to moderate iodine deficiency, defined as those who excrete less than 10 mg of iodine per 100 ml urine.[15] Iodine is no longer added to table salt in the UK, and those who do not regularly consume seafood or sea salt may be at risk of iodine deficiency.

Iron

Red cell basic ferritin is a measure of iron sufficiency, and was found to be significantly lower in 224 patients with hearing loss compared with normal controls.[16]

In another study, 426 patients with idiopathic sudden hearing loss were found to have low haemoglobin and serum iron levels. They were administered either iron or vitamin supplements or medications. Hearing improvement was achieved in 53% of those administered iron supplements, a result significantly better than the other groups.[17]

Magnesium

Three hundred young healthy individuals with normal hearing, undergoing military training with exposure to high noise levels, were given either magnesium aspartate or placebo. Thresholds for noise-induced permanent hearing loss were significantly higher in the magnesium group. Magnesium supplementation was therefore found to be protective against damage to hearing caused by exposure to noise.[18]

The reasons for the protection afforded by magnesium are not clear. Researchers hypothesize that a low concentration of magnesium in the perilymph fluid of the inner ear may cause energy depletion and irreversible damage to the hair cells found in the cochlea.

Zinc

Zinc supplements may help tinnitus. In one study they were given to tinnitus sufferers with low blood zinc levels, resulting in a significant improvement in symptoms in 52% of cases, especially in cases of continuous tinnitus.[19]

Nutritional Therapy for Hearing Problems

Oily fish (herrings, salmon, mackerel, sardines) and essential polyunsaturated oils Help to reduce platelet adhesiveness, lower cholesterol and maintain red cell deformability.[4]

lue and purple berries and Ginkgo biloba supplements Rich in flavonoids, these have long been known to support the microcirculation.[5] [6]

Low-fat diet rich in fresh fruit and vegetables To help lower cholesterol.

Copper (found in nuts, pulses, shellfish, whole-grains)[7] Copper is also needed for a healthy microcirculation - possibly the reason why it is considered in Rudolph Steiner's anthroposophical medicine system to be a warming element.

Warming spices such as ginger and chillies Act as circulatory stimulants.

Nuts Very rich in arginine, needed to make nitric oxide which helps to keep blood vessels dilated. Also rich in vitamin E and essential fatty acids.

Correct food allergies Glue ear is a common cause of hearing loss in children and is frequently caused by intolerances to foods such as wheat or dairy products.

Correct nutritional deficiencies If hearing problems or low nutritional status persist despite an improved diet, consider supplementation with appropriate nutrients.

Case History

Annie, aged 55, had suffered from chronic tinnitus for 11 years, with bouts of extreme vertigo. She could literally walk into walls at these times, and experienced extreme confusion. Her doctors told her she had Menière's disease, or possibly acoustic neuroma - a tumour in her auditory canal - and suggested surgery.

One hot summer day Annie was gardening outside, felt overheated and went into the house to pour herself a big glass of diet cola, her favourite drink. On returning to the garden, within minutes she felt nauseated, foggy, confused and the world started spinning. Then she had a small seizure.

This was a terrifying experience. When she could get up off the ground, Annie took a tranquillizer and lay down. Shortly afterwards she received a phone call from her brother Tom and happened to mention that before her 'attack' she had been drinking diet cola. He asked Annie what the ingredients were. When she read out the list and got to the word 'Aspartame', he stopped her. Tom was an airline pilot. He told Annie that he and other pilots were warned not to consume anything with aspartame in it for 48 hours prior to flying. He said it was well known to cause extreme vertigo, fogginess and even blackouts. Aspartame is the scientific name for NutraSweet(r), an artificial sweetener which is now added to most low-calorie or 'diet' foods and drinks.

It had never occurred to Annie that there was a connection between her favourite drink and her illness. So she tested herself - no diet cola for four days. All dizziness and confusion disappeared. Only tinnitus remained. Then she drank a glass of diet cola. Wham! Extreme vertigo, confusion and nausea - almost immediately.

As long as Annie stays clear of aspartame she is symptom-free. Only tinnitus is left lingering. Yet no doctor has ever asked her if she regularly ingests anything with aspartame in it - despite the fact that it appears to be a neurological toxin. There is a massive volume of data on aspartame and Annie was appalled to discover that there are hundreds of cases of people like her, who have gone from doctor to doctor seeking an answer to or relief from these debilitating symptoms.

References

1. Houston DK et al. Age-related hearing loss, vitamin B-12, and folate in elderly women. American Journal of Clinical Nutrition. 69(3): 564-571. March, 1999.
2. Strome M et al. Hyperlipidemia in association with childhood sensorineural hearing loss. Laryngoscope. 98(2): 165-9. 1988.
3. Ernst E. Ginkgo biloba for tinnitus: a review. Clin Otolaryngol. 24: 164-167. 1999. (Reported in The Experts Speak. Clinical Pearls (compilation CD), ITServices. Sacramento. USA. 1999.
4. Terano T et al. Docosahexaenoic acid supplementation improves the moderately severe dementia from thrombotic cerebrovascular diseases. Lipids. 34(Suppl): S345-S346.1999.
5. Oken BS et al. The efficacy of Ginkgo biloba on cognitive function in Alzheimer's disease. Arch Neurol. 55: 1409-1415. Nov, 1998.
6. Bartolo M and Antignani PL. Drug therapy of venous insufficiency. Phlebologie (French). 38(2): 353-7. Apr-Jun, 1985.
7. Schuschke DA. Dietary copper in the physiology of the microcirculation. Journal of Nutrition. 127: 2274-2281. 1997.
8. Browning GG et al. Blood viscosity as a factor in sensorineural hearing impairment. Lancet. 1(8473): 121-3. 1986.
9. Jandak J et al. Alpha-tocopherol, an effective inhibitor of platelet adhesion. Blood. 73(1): 141-9. 1989.
10. Romeo G. The therapeutic effect of vitamins A and E in neurosensory hearing loss. Acta Vitaminol Enzymol. 7(Suppl): 85-92. 1985.
11. Shemesh Z et al. Vitamin B12 deficiency in patients with chronic tinnitus and noise-induced hearing loss. Am J Otolaryngol. 14(2): 94-9. 1993.
12. Brookes GB. Vitamin D deficiency and otosclerosis. Otolaryngol Head Neck Surg. 93(3): 313-21. 1985.
13. Brookes GB. Vitamin D deficiency and deafness: 1984 update. Am J Otol. 6(1): 102-7. 1985.
14. Ikeda K et al. Evaluation of vitamin D metabolism in patients with bilateral sensorineural hearing loss. Am J Otol. 10(1): 11-3. Jan 1989.
15. Valeix P et al. Relationship between urinary iodine concentration and hearing capacity in children. Eur J Clin Nutr. 48(1): 54-9. Jan, 1994.
16. Sun AH et al. Red cell basic ferritin concentration in sensorineural hearing loss. ORL J Otorhinolaryngol Relat Spec. 53(5): 270-2. 1991.
17. Sun AH et al. Idiopathic sudden hearing loss and disturbance of iron metabolism. A clinical survey of 426 cases. ORL J Otorhinolaryngol Relat Spec. 54(2): 66-70. 1992.
18. Attias J et al. Oral magnesium intake reduces permanent hearing loss induced by noise exposure. Am J Otolaryngol. 15(1): 26-32. 1994.
19. Gersdorff M et al. The zinc sulfate overload test in patients suffering from tinnitus associated with low serum zinc. Preliminary report (French). Acta Otorhinolaryngol Belg. 41(3): 498-505. 1987.