Thursday, March 29, 2018

The human ear is not built for listening to music


Your ears cannot protect themselves from even relatively loud music.


The human ear is not built for listening to music

Although the ear has reflexes which protects it against certain types of noise, there is not much it can do when the noise level goes above 120 dB.

The reaction time - 30 to 40 milliseconds - is a limitation in itself, as that is far too little to protect the ear from noise created by human beings.

The combination of three different factors could result in hearing impairment after listening to music:
  • The duration of time listening
  • Closeness to the source of the sound
  • How loud the music is played
No matter how loud the music is turned up when you listen to it, the basic rule is that the longer you listen, the more you stress the muscles in the inner ear. Fatigue of the ear may result in a temporary threshold shift, limiting the amount of quiet sounds that you can hear.

And the more you subject your ears to fatigue, the more likely it is that you will be permanently hearing-impaired.

The middle ear

What is the middle ear? The middle ear is the part of the ear between the eardrum and the oval window. The middle ear transmits sound from the outer ear to the inner ear. The middle ear consists of three bones: the hammer (malleus), the anvil (incus) and the stirrup (stapes), the oval window, the round window and the Eustrachian tube.
 

The middle ear

The bones of the middle ear

The eardrum is very thin, measures approximately 8-10 mm in diameter and is stretched by means of small muscles. The pressure from sound waves makes the eardrum vibrate.
The vibrations are transmitted further into the ear via three bones in the middle ear: the hammer (malleus), the anvil (incus) and the stirrup (stapes). These three bones form a kind of bridge, and the stirrup, which is the last bone that sounds reach, is connected to the oval window.

The oval window

What is the oval window? The oval window is a membrane covering the entrance to the cochlea in the inner ear. When the eardrum vibrates, the sound waves travel via the hammer and anvil to the stirrup and then on to the oval window.
When the sound waves are transmitted from the eardrum to the oval window, the middle ear is functioning as an acoustic transformer amplifying the sound waves before they move on into the inner ear. The pressure of the sound waves on the oval window is some 20 times higher than on the eardrum.

The pressure is increased due to the difference in size between the relatively large surface of the eardrum and the smaller surface of the oval window. The same principle applies when a person wearing a shoe with a sharp stiletto heel steps on your foot: The small surface of the heel causes much more pain than a flat shoe with a larger surface would.

The round window

The round window in the middle ear vibrates in opposite phase to vibrations entering the inner ear through the oval window. In doing so, it allows fluid in the cochlea to move.

The Eustachian tube

What is the Eustachian tube? The Eustachian tube is also found in the middle ear, and connects the ear with the rearmost part of the palate. The Eustachian tube’s function is to equalise the air pressure on both sides of the eardrum, ensuring that pressure does not build up in the ear. The tube opens when you swallow, thus equalising the air pressure inside and outside the ear.

In most cases the pressure is equalised automatically, but if this does not occur, it can be brought about by making an energetic swallowing action. The swallowing action will force the tube connecting the palate with the ear to open, thus equalising the pressure.

Built-up pressure in the ear may occur in situations where the pressure on the inside of the eardrum is different from that on the outside of the eardrum. If the pressure is not equalised, a pressure will build up on the eardrum, preventing it from vibrating properly. The limited vibration results in a slight reduction in hearing ability. A large difference in pressure will cause discomfort and even slight pain. Built-up pressure in the ear will often occur in situations where the pressure keeps changing, for example when flying or driving in mountainous areas.

Noise and Hearing

Protection Fact

Sheet

One in ten Citizens has a hearing loss that affects his or her ability to understand normal speech. Excessive noise exposure is the most common cause of hearing loss. Some workers with long-term hearing loss have developed ways of adapting to the gradual onset of the disease. The effect of noise is real and can be devastating. Workers who also develop tinnitus (constant ringing in the ears) can find this to be unbearable. The important thing is that no matter what your present level of hearing loss, it is never too late or too hard to prevent further damage. Workers who already have serious hearing loss have even greater reason for saving the hearing they have left. The following information should provide reasons for eliminating noise hazards at work and in everyday life.
 
Can Noise Really Hurt My Ears?
Yes, noise can be dangerous. If it is loud enough and lasts long enough, it can damage your hearing. Hearing damage can be caused by several factors other than noise, but noise-induced hearing loss is different in one important way, it can be reduced or prevented altogether.

Can I “Toughen Up” My Ears?
No. If you think you have grown used to a loud noise, it probably has damaged your ears, and there is no treatment—no medicine, no surgery, not even a hearing aid—that completely restores your hearing once it is damaged by noise.

How Does the Ear Work?
The ear has three main parts: the outer, middle, and inner ear. The outer ear (the part you can see) opens into the ear canal. The eardrum separates the ear canal from the middle ear. Small bones in the middle ear help transfer sound to the inner ear. The inner ear contains the auditory (hearing) nerve, which leads to the brain.

Any source of sound sends vibrations or sound waves into the air. These funnel through the ear opening, down the ear canal, and strike your eardrum, causing it to vibrate. The vibrations are passed to the small bones of the middle ear, which transmit them to the hearing nerve in the inner ear. Here, the vibrations become nerve impulses and go directly to the brain, which interprets the impulses as sound: music, a slamming door, a voice, etc. When noise is too loud, it begins to kill the nerve endings in the inner ear. As the exposure time to loud noise increases, more and more nerve endings are destroyed. As the number of nerve endings decreases, so does your hearing. There is no way to restore life to dead nerve endings; the damage is permanent.

How Can I Tell If a Noise Is Dangerous?
People differ in their sensitivity to noise. As a general rule, noise may damage your hearing if you have to shout over background noise to make yourself heard, the noise hurts your ears, it makes your ears ring, or you have difficulty hearing for several hours after exposure to the noise. Sound can be measured scientifically in two ways: intensity, or loudness of sound, is measured in decibels; pitch is measured in frequency of sound vibrations per second. A low pitch, such as a deep voice or a tuba, makes fewer vibrations per second than a high voice or violin.

What Does Frequency of Sound Vibration Have to Do with Hearing Loss?
Frequency is measured in cycles per second, or Hertz (Hz). The higher the pitch of the sound, the higher the frequency. Young children, who generally have the best hearing, can often distinguish sounds from about 20 Hz, such as the lowest note on a large pipe organ, to 20,000 Hz, such as the high shrill of a dog whistle that many people are unable to hear.

Human speech, which ranges from 300 to 4,000 Hz, sounds louder to most people than noises at very high or very low frequencies. When hearing impairment begins, the high frequencies are usually lost first, which is why people with hearing loss often have difficulty hearing the high pitched voices of women and children. Loss of high frequency hearing also can distort sound, so that speech is difficult to understand even though it can be heard. People with hearing loss often have difficulty detecting differences between certain words that sound alike, especially words that contain S, F, SH, CH, H, or soft C sounds because the sound of these consonants is in a much higher frequency range than vowels and other consonants.

What About Decibels?
Intensity of sound is measured in decibels (dB). The scale runs from the faintest sound the human ear can detect, which is labeled 0 dB, to over 180 dB, the noise at a rocket pad during launch. Decibels are measured logarithmically. This means that as decibel intensity increases by units of 10, each increase is 10 times the lower figure. Thus, 20 decibels is 10 times the intensity of 10 decibels, and 30 decibels is 100 times as intense as 10 decibels.

How High Can the Decibels Go without Affecting My Hearing?
Many experts agree that continual exposure to more than 85 decibels is dangerous.

Does the Length of Time I Hear a Noise Have Anything to Do with the Danger to My Hearing?
It certainly does. The longer you are exposed to a loud noise, the more damaging it may be. Also, the closer you are to the source of intense noise, the more damaging it is. Every gunshot produces a noise that could damage the ears of anyone in close hearing range. Large bore guns and artillery is the worst because they are the loudest. But even cap guns and firecrackers can damage your hearing if the explosion is close to your ear. Anyone who uses firearms without some form of ear protection risks the potential for hearing loss. Recent studies show an alarming increase in hearing loss in youngsters. Evidence suggests that loud music along with increased use of portable radios with earphones may be responsible for this phenomenon.

Can Noise Affect More Than My Hearing?
A ringing in the ears, called tinnitus, commonly occurs after noise exposure, and it often becomes permanent. Some people react to loud noise with anxiety and irritability, an increase in pulse rate and blood pressure, or an increase in stomach acid. Very loud noise can reduce efficiency in performing difficult tasks by diverting attention from the job.

Who Should Wear Hearing Protectors?
If you must work in an excessively noisy environment, you should wear protectors. You should also wear them when using power tools, noisy yard equipment, firearms, or riding a motorcycle or snowmobile.

What Are the Laws for On-the-Job Exposure?
• Habitual exposure to noise above 85 dB will cause a gradual hearing loss in a significant number of individuals, and louder noises will accelerate this damage.
• For unprotected ears, the allowed exposure time decreases by one-half for each 5 dB increase in the average noise level. For instance, exposure is limited to 8 hours at 90 dB, 4 hours at 95 dB, and 2 hours at 100 dB.
• The highest permissible noise exposure for the unprotected ear is 115 dB for 15 minutes/day. Any noise above 140 dB is not permitted.

The Occupational Safety and Health Administration (OSHA), Standards 29 Code of Federal Regulations (CFR) 1910.095 (General Industry) and 29 CFR 1926.52 (Construction Industry) states that each employer will implement and maintain a written Hearing Conservation Program for their respective industries. In order to determine if a hearing conservation program is needed, a site noise evaluation must be done. This can be accomplished by conducting a noise evaluation, noise monitoring, or Job Hazard Analysis (JHA). If during these tests a noise is found to be 85 dB or higher, a written conservation program will need to be written. OSHA requires a yearly hearing test for the approximately five million workers exposed to an average of 85 dB or more of noise during an 8-hour workday. If noise is found to be greater than 95 dB, hazard controls must be used.

Ideally, noisy machinery and work places should be engineered to be more quiet or the worker’s time in the noise should be reduced; however, the cost of these actions is often prohibitive. As an alternative, individual hearing protectors are required when noise averages more than 90 dB during an 8-hour day. When noise measurements indicate that hearing protectors are needed, the employer must offer at least one type of earplug and one type of earmuff without cost to employees. If the yearly hearing tests reveal hearing loss of 10 dB or more in higher pitches in either ear, the worker must be informed and must wear hearing protectors when noise averages more than 85 dB for an 8-hour day. Larger losses of hearing and/or the possibility of ear disease should result in referral to an ear, nose and throat physician (otolaryngologist).

What Are Hearing Protectors? How Effective Are They?
Hearing protection devices decrease the intensity of sound that reaches the eardrum. Hearing Protectors come in two forms: earplugs and earmuffs. Earplugs are small inserts that fit into the outer ear canal. They must be snugly sealed so the entire circumference of the ear canal is blocked. An improperly fitted, dirty or worn-out plug may not seal and can irritate the ear canal. They are available in a variety of shapes and sizes to fit individual ear canals and can be custom made. For people who have trouble keeping them in their ears, they can be fitted to a headband.

Earmuffs fit over the entire outer ear to form an air seal so the entire circumference of the ear canal is blocked, and they are held in place by an adjustable band. Earmuffs will not seal around eyeglasses or long hair, and the adjustable headband tension must be sufficient to hold earmuffs firmly around the ear.
 
Properly fitted earplugs or muffs reduce noise 15 to 30 dB. The better earplugs and muffs are approximately equal in sound reductions, although earplugs are better for low frequency noise, and earmuffs for high frequency noise. Simultaneous use of earplugs and muffs usually adds 10 to 15 dB more protection than either used alone. Combined use should be considered when noise exceeds 105 dB.

Why Can’t I Just Stuff My Ears with Cotton?
Ordinary cotton balls or tissue paper wads stuffed into the ear canals are very poor protectors; they reduce noise only by approximately 7 dB and are not considered as adequate protection.

What Are the Common Problems of Hearing Protectors?
Studies have shown that one-half of the workers wearing hearing protectors receive one-half or less of the noise reduction potential of their protectors because these devices are not worn continuously while in noise or because they do not fit properly. A hearing protector that gives an average of 30 dB of noise reduction if worn continuously during an 8-hour workday becomes equivalent to only 9 dB of protection if taken off for one hour in the noise. This is because decibels are measured on a logarithmic scale, and there is a 10-fold increase in noise energy for each 10 dB increase.

During the hour with unprotected ears, the worker is exposed to 1,000 times more sound energy than if earplugs or muffs had been worn. In addition, noise exposure is cumulative. So the noise at home or at play must be counted in the total exposure during any one day. A maximum allowable while on-the-job exposure followed by an exposure to noisy lawnmower or loud music will definitely exceed the safe daily limits. Even if earplugs and/or muffs are worn continuously while in noise, they do little good if there is an incomplete air seal between the hearing protector and the skin. When using hearing protectors, you will hear your own voice as louder and deeper. This is a useful sign that the hearing protectors are properly positioned.

Can I Hear Other People and Machine Problems If I Wear Hearing Protectors?
Just as sunglasses help vision in very bright light, so do hearing protectors enhance speech understanding in very noisy places. Even in a quiet setting, a person with normal-hearing who is wearing hearing protectors should be able to understand a regular conversation. Hearing protectors do slightly reduce the ability of those with damaged hearing or poor comprehension of language to understand normal conversation. However, it is essential that persons with impaired hearing wear earplugs or muffs to prevent further inner ear damage. It has been argued that hearing protectors might reduce a worker’s ability to hear the noises that signify an improperly functioning machine. However, most workers readily adjust to the quieter sounds and can still detect such problems.

What If My Hearing Is Already Damaged? How Can I Tell?
Hearing loss usually develops over a period of several years. Since it is painless and gradual, you might not notice it. What you might notice is a ringing or other sound in your ear (called tinnitus), which could be the result of long-term exposure to noise that has damaged the hearing nerve. Or, you may have trouble understanding what people say; they may seem to be mumbling, especially when you are in a noisy place such as in a crowd or at a party. This could be the beginning of high-frequency hearing loss; a hearing test will detect it.

If you have any of these symptoms, you may have nothing more serious than impacted wax or an ear infection, which might be easily corrected. However, it might be hearing loss from noise. In any case, take no chances with noise—the hearing loss it causes is permanent. If you suspect a hearing loss, consult a physician with special training in ear care and hearing disorders (called an otolaryngologist or otologist). This doctor can diagnose your hearing problem and recommend the best way to manage it.
It is possible for you to enjoy an active lifestyle and protect your hearing from damage. While many everyday activities generate enough noise to cause hearing loss, with a little awareness and reasonable care, most people can expect to maintain their hearing throughout their life. Exposure to noise causes hearing damage and is almost always preventable.

Remember to practice safety. Don’t learn it by accident.

1. NRR Ratings
The performance of earplugs and earmuffs varies between brands and styles. One way to choose a hearing protector is to compare Noise Reduction Ratings. The Noise Reduction Rating, or NRR, measures the muff's or plug's ability to block out noise or "attenuate"; sound. This measurement is stated in decibels; a plug with an NRR of 26 blocks out a maximum of 26 decibels of noise. The NRR listed is the maximum protection that could be achieved if the plug fit the wearer perfectly and was inserted correctly. In most work situations attenuation is half of the listed NRR. For example, if the NRR is 30 the hearing protector most likely blocks out 15 decibels of noise.

All of the earplugs and muffs we stock have been tested by an accredited laboratory that assigned an NRR rating. As you look through our selection, look for the NRR rating by each style of protection.


2. How damaging are your work activities?
The chart below lists common sounds and their decibel ratings.

0 dB 
Lowest audible sound
 
50 dB
Quiet empty barn, babbling trout stream, gentle breeze
 
60 dB
 
Normal conversation
 
70 dB
 
Chicken coop, farrowing area
85 dB 
 

Tractor or combine idling, barn cleaner, conveyor, elevator: You can begin to lose your hearing at this dB if you're exposed to it for eight (8) hours or more per day.
90 dB
 
 
 

Blower compressor, pneumatic wrench, chopping silage (no cab), full-throttle mower: If you are exposed to noises at this level for four (4) hours or more per day, hearing loss can occur.
100 dB 
 

Tractor at 80% load, squealing sows, power tools, hand-held metal grinder: One hour of exposure per day is the limit at this decibel level.
110 dB 

Full-throttle combine, 10-HP vane-axial barn fan: Anything over 15 minutes exposure per day can cause damage.
120 dB 
Thunderclap (near), sandblasting, bad muffler, old chain saw: The danger is immediate.
140 dB 

Gunshot, engine back-fire, dynamite blast, jet engine. Any length of exposure time is dangerous and may actually cause ear pain.
  
  
  
  
  
  
  
  
  
  
As noise gets louder, damage can occur sooner. There is no "cure" for hearing loss. This chart is only a guideline. Anything over 85 dB can be damaging to your hearing.
Chart provided courtesy of the National Farm Medicine Center

0 dB
Lowest audible sound
 
50 dBQuiet empty barn, babbling trout stream, gentle breeze

60 dB

Normal conversation

70 dB

Chicken coop, farrowing area
85 dB

Tractor or combine idling, barn cleaner, conveyor, elevator: You can begin to lose your hearing at this dB if you're exposed to it for eight (8) hours or more per day.
90 dB

Blower compressor, pneumatic wrench, chopping silage (no cab), full-throttle mower: If you are exposed to noises at this level for four (4) hours or more per day, hearing loss can occur.
100 dB

Tractor at 80% load, squealing sows, power tools, hand-held metal grinder: One hour of exposure per day is the limit at this decibel level.
110 dB
Full-throttle combine, 10-HP vane-axial barn fan: Anything over 15 minutes exposure per day can cause damage.
120 dB
Thunderclap (near), sandblasting, bad muffler, old chain saw: The danger is immediate.
140 dB
Gunshot, engine back-fire, dynamite blast, jet engine. Any length of exposure time is dangerous and may actually cause ear pain.

3. How do you know if noise is damaging your hearing?
You may have a problem if you:

  • Hear ringing, other noises or a fullness in your ears
  • Can't hear people when they talk to you
  • Can't hear high pitched or soft sounds.

Noise Indused Hearing Loss (aka Noise Induced Deafness) - Inner Ear

The inner ear


Human Ear Anatomy

What is the inner ear? The inner ear is the innermost part of the ear, which consist of the cochlea, the balance mechanism, the vestibular and the auditory nerve. Read more in this article about the inner ear’s anatomy, how the inner ear functions and the parts of the inner ear.
 



Once the vibrations of the eardrum have been transmitted to the oval window, the sound waves continue their journey into the inner ear.


The inner ear is a maze of tubes and passages, referred to as the labyrinth. In the labyrinth can be found the vestibular and the cochlea.

The cochlea

The cochlea is a portion of the inner ear that looks like a snail shell (cochlea is Greek for snail.) The cochlea receives sound in the form of vibrations, which cause the stereocilia to move. The stereocilia then convert these vibrations into nerve impulses which are taken up to the brain to be interpreted.

Related image

Related image

 Structural diagram of the cochlea showing how fluid pushed in at the oval window moves, deflects the cochlear partition, and bulges back out at the round window.

In the cochlea, sound waves are transformed into electrical impulses which are sent on to the brain. The brain then translates the impulses into sounds that we know and understand.


What is the cochlea and what is the function of the cochlea?

 The cochlea resembles a snail shell or a wound-up hose and is filled with a fluid called perilymph and contains two closely positioned membranes. These membranes form a type of partition wall in the cochlea. However, in order for the fluid to move freely in the cochlea from one side of the partition wall to the other, the wall has a little hole in it (the helicotrema). This hole is necessary, in ensuring that the vibrations from the oval window are transmitted to all the fluid in the cochlea.

When the fluid moves inside the cochlea, thousands of microscopic hair fibres inside the partition wall are put into motion. There are approximately 24,000 of these hair fibres, arranged in four long rows.

As the fluid moves, the cochlear partition (basilar membrane and organ of Corti) moves; thousands of hair cells sense the motion via their stereocilia, and convert that motion to electrical signals that are communicated via neurotransmitters to many thousands of nerve cells.

Plus the fluid in the cochlea is a necessity for moving the hair cells and triggering the electrical impulse necessary for hearing. Air alone, especially ... Anneloes' answer is the most plausible, the cilia wouldn't move as well to excitation. ... Almost everything inside our body is fluid immersed, so that is the default situation.

However, in order for the fluid to move freely in the cochlea from one side of the partition wall to the other, the wall has a little hole in it (the helicotrema). This hole is necessary, in ensuring that the vibrations from the oval window are transmitted to all the fluid in the cochlea.

The auditory nerve

What is the auditory nerve? The auditory nerve is a bundle of nerve fibres that carry information between the cochlea in the inner ear and the brain. The function of the auditory nerve is to transmit signals from the inner ear to the brain.

The hair fibres in the cochlea are all connected to the auditory nerve and, depending on the nature of the movements in the cochlear fluid, different hair fibres are put into motion.


When the hair fibres move they send electrical signals to the auditory nerve which is connected to the auditory centre of the brain. In the brain the electrical impulses are translated into sounds which we recognise and understand. As a consequence, these hair fibres are essential to our hearing ability. Should these hair fibres become damaged, then our hearing ability will deteriorate.

The vestibular – the balance mechanism


What is the vestibular? The vestibular is another important part of the inner ear. The vestibular is the organ of equilibrium. The vestibular’s function is to register the body's movements, thus ensuring that we can keep our balance.

The vestibular consists of three ring-shaped passages, oriented in three different planes. All three passages are filled with fluid that moves in accordance with the body's movements. In addition to the fluid, these passages also contain thousands of hair fibres which react to the movement of the fluid sending little impulses to the brain. The brain then decodes these impulses which are used to help the body keep its balance.


attenuation
ətɛnjʊˈeɪʃ(ə)n
noun
the reduction of the force, effect, or value of something.


"human security required the attenuation of a wide range of threats to people"


-the reduction of the amplitude of a signal, electric current, or other oscillation.

-
"the products are used mostly by aircraft manufacturers for noise attenuation in engine housings"
 

Extra Protection: Wearing Earmuffs and Earplugs in Combination


INTRODUCTION:

When it's really loud, so loud that a properly worn single hearing protection device (HPD) can't provide safe listening, what is a hearing conservationist to do? Reducing exposure time or other administrative controls are certainly options to consider. Another option may well be the use of earmuffs and earplugs in combination, commonly called 'dual protection.' As you probably guessed, dual protection has its own assets, liabilities, and limitations. This article will explore them.

OVERVIEW:

It is generally recommended that one should consider the use of dual protection when 8-hour time-weighted-average (TWA) exposures exceed 105 dBA as required in the new Mine Safety and Health Administration (MSHA, 1999) noise regulation, which went into effect September, 2000. For an extra margin of safety one may wish to consider implementation of dual protection when exposures exceed 100 dBA as is suggested in the 1998 NIOSH Revised Criteria for Occupational Noise Exposure. Using dual protection at levels or exposures below that is problematic due to interference with speech-based communication. However, once noise levels exceed 100 dBA unaided speech communication (i.e. communication without electronic amplifiers and earphones) is nearly impossible anyway. Therefore, no additional detriment is created by the extra protection.

Other difficulties in mandating the use of dual protection in lower-level noise include motivating employees to wear devices properly, and subsequent enforcement of their use. Although the 'annoyance' of a sound is not a good measure of its potential hazard or the need for hearing protection, its annoyance (or lack thereof) can substantially impact the ease with which use of HPDs can be mandated and effectively enforced. For many, exposures below 100 dBA just don't seem loud enough or annoying enough to warrant single protection -- let alone dual protection! If the sounds are not annoying, insisting on use of dual protection can be considerably more difficult than trying to obtain compliance with the use of a single product alone.


PERFORMANCE CONSIDERATIONS:

Earplugs worn in combination with earmuffs, helmets, or communications headsets, typically provide greater protection than either device alone. However, the attenuation of the combination is not equal to ...

 



[Figure 1 - An example of the attenuation provided by an earplug, and earmuff, and the two devices together, as compared to the bone-conduction limits to hearing protector attenuation (the reduction of the force, effect, or value of something.)]
 
 
 
...the sum of the individual attenuation values (Berger, 1983), as illustrated in Figure 1. Note for example; at 1000 Hz the combination of a 26-dB plug and a 34-dB muff does not yield 60-dB overall, but rather about 41 dB. The principal reason is the bone-conduction (BC) limits to attenuation, which are also illustrated in Figure 1. The BC limits represent sound that effectively flanks or bypasses the HPD to directly stimulate the middle and inner ears of the wearer. Another limitation on the performance of dual protection is that the plug and muff interact mechanically with each other, and thus do not behave as two completely independent attenuators.

No empirical or theoretically derived equations are available that can predict the attenuation of an earplug and earmuff combination with sufficient accuracy to be useful. At individual frequencies the incremental gain in performance for dual hearing protection varies from approximately 0 to 15 dB over the better single device, but because of the dip in BC limits at 2000 Hz, the gain varies from 0 to only a few decibels at that frequency. Attenuation changes very little when different earmuffs are used with the same earplug, but for a given earmuff the choice of earplug is critical for attenuation at frequencies below 2000 Hz. At and above 2000 Hz, all dual-protection combinations provide attenuation essentially equal to the limitations imposed by the bone-conduction pathways, approximately 40 to 50 dB, depending upon frequency. As a rule of thumb, the OSHA procedure of computing the dual protection by adding 5 dB to the Noise Reduction Rating (NRR) of the more protective of the two devices is a reasonable approximation.

For the best estimate of dual-protection performance a real-ear attenuation at threshold measurement of the combination being evaluated should be conducted. Some manufacturers of hearing protectors can provide such data. Better yet, real-world attenuation values should be considered (Berger, 2000). Unfortunately few of those types of data are available. One study, of which the author is aware, suggests that the highest attenuation in terms of an NRR-like number, that can realistically be obtained for about 84% of the population, is about 25 dB (Hachey and Roberts, 1983). This was observed in one study of a foam earplug worn in combination with a small-volume plastic earmuff. Thus when TWAs exceed about 110 dB, even dual protection is likely to be inadequate. At such times, limited durations of exposure and twice-annual monitoring audiometry should be considered.

The use of dual HPDs is especially recommended when high-intensity noise is dominated by energy at or below 500 Hz since it is in this frequency range that the attenuation of single HPDs will be the least and the potential benefits from dual protection are the greatest.
 
APPLICATION CONSIDERATIONS:
For maximum protection not only must a muff and plug be worn together, but both devices must be worn correctly and consistently. Even short periods of disuse can dramatically reduce the effective protection. At low frequencies, the earplug can be the most important part of the combination and thus its correct use is vital. Individual training is especially important for the high-noise otohazardous areas in which dual protection is likely to be worn.

Another issue is the ability to monitor correct usage. This is complicated once the muff is in place since the fit of the plug cannot be readily assessed by supervisors unless they stop and ask the employee to lift one or both earmuff cups. In fact, when dual protection is apparently being used, whether or not the plug is actually being worn at all cannot be ascertained by simple passing observation.


 


  An interesting solution to this problem has recently been provided by one manufacturer in the  form of clear earmuffs with a special donut-shaped foam absorber inside that allows clear viewing of the earplug (see Figure 2).

The absorber has been designed so as not to degrade the earmuff's attenuation, so that even if the muff is worn alone, it functions as well as its standard opaque counterpart.





Figure 2: A new style of dual protection that incorporates the use of a foam earplug worn under a clear earmuff cup (Peltor/E#149;A#149;R High Performance Series).


CONCLUDING REMARKS:

It has been observed that 97% of industrial noise exposures are less than 100 dBA TWA. Therefore, in most cases, dual protection is not going to be necessary or appropriate. However, for those situations in which noise exceeds 100 dBA, as found in a wide range of industries from on-line aircraft engine maintenance to metal riveting, dual protection may be an appropriate solution.

Although the casual observer of HPD's labeled NRRs might conclude that in almost any noise exposure employees will be adequately protected (because labeled NRRs commonly range from 22 - 33 dB), that is far from the actual case. Many studies in the past 20 years have clearly demonstrated that in real-world environments HPD attenuation falls far short of the EPA-mandated NRRs that have appeared on packaging since the early 1980s (Berger et al., 1996). Thus in critical high-noise instances, where TWAs exceed 100 to 105 dBA, the use of dual hearing protection is warranted.


REFERENCES:

  1. Berger, E. H. (1983). 'Laboratory attenuation of earmuffs and earplugs both singly and in combination,' Am. Ind. Hyg. Assoc. J. 44(5), 321-329.


  2. Berger, E. H. (2000). 'Hearing protection devices,' Chapter 10 in The Noise Manual, 5th Edition, edited by E. H. Berger, L. H. Royster, J. D. Royster, D. P. Driscoll, and M. Layne, Am. Ind. Hyg. Assoc., Fairfax, VA, 379-454.

  3. Berger, E. H., Franks, J. R., and Lindgren, F. (1996). 'International review of field studies of hearing protector attenuation,' in Scientific Basis of Noise-Induced Hearing Loss, edited by A. Axlesson, H. Borchgrevink, R. P. Hamernik, P. Hellstrom, D. Henderson, and R. J. Salvi, Thieme Medical Publ., Inc., New York, NY, 361-377.

  4. Hachey, G. A. and Roberts, J. T. (1983). 'Real world effectiveness of hearing protection,' presented at Am. Ind. Hyg. Conf., Phila., PA, abstract 462.

  5. MSHA (1999). 'Health standards for occupational noise exposure; final rule,' Mine Safety and Health Administration, 30 CFR Part 62, 64 Fed. Reg., 49458-49634, 49636-49637.

  6. NIOSH (1998). 'Criteria for a recommended standard: occupational noise exposure; revised criteria,' National Institute for Occupational Safety and Health, U. S. Dept. HHS, Report DHHS (NIOSH) 98-126, Cincinnati, OH.

  7. Acknowledgment: This article was originally prepared for Occupational Health & Safety magazine's October 2000 issue. The author and the editor of OH&S have graciously allowed Audiology Online to re-edit and republish this paper here, for educational purposes. We are grateful to Mr. Berger (author)and Mr. Laws (editor) for their approval and kindness in this project.
     
     
     

     

    Wednesday, March 28, 2018

    Cancer Treatment Using Vitammin B-17



    The Truth about ´Vitamin´ B-17
    Separating B-17 Myth From Reality

    Amygdalin or laetrile? B-17 as a cancer ´cure´ is one of the most controversial subjects in ´Alternative cancer medicine´. Is there research to support it as an alternative cancer treatment? Is there research to support it as a complementary therapy? Is there research to support B-17 as a cure for cancer? Here we bring you one of the most comprehensive and accurate reviews on the Internet today (Written by Editor, Chris Woollams, M.A. Oxon, Biochemistry). 

    The controversy was re-opened in October 2014 when researchers (Makarevic et al; PLOSone) showed that natural B-17 (amygdalin) dose-dependently reduced growth and proliferation of cancer cells in vitro (See Cancer Watch - Click Here).

    Controversy was furthered in May 2016, when the Food Standards Authority (FSA) in the UK talked about banning the sale of Apricot Kernels. So, a Government that puts a proven class A carcinogen (fluoride) in our water supplies is going to ban a food they don´t even correctly understand - they say, like many ignorants, that 30 of them ´contain cyanide´. Do they understand that for years people have eaten foods like marzipan in cakes. It was made from Apricot Kernels. UK nurses were even told to eat an apricot, then break the nut and eat the pip for health reasons, although I am going back 65 years to when my mother was a nurse.

    What you are about to read is the Truth, the whole truth and not the rubbish the skeptics, people with agendas and propaganda-pushers, and generally ill-informed people would have you believe.

    B-17: Laetrile is not the same as Amygdalin

    Firstly, let´s get one thing straight: Beware the articles that talk of eating pips and seeds and call the active ingredient Laetrile. The writers are making a simple, but fundamental error. How many more will they make?
    It is important to differentiate the use of natural amygdalin from Apricot Kernels, and Laetrile, which is a concentrated, synthetic drug.

    But, when it comes to B-17, confusion exists everywhere and absolute rubbish is often talked, even from supposedly ´top´ websites.

    B-17: Basic facts

    A typically ignorant exchange happened on February 14th 2006, when the UK´s Daily Mail ran a headline ´Cancer Cures or Quackery?´ under which six alternative practitioners recommended ´alternative´ cancer cures (their words not mine) to a reporter posing as a cancer patient. To quote, ´One therapy was ´B-17 metabolic therapy or laetrile´ (sic).

    Two UK cancer ´experts´, Professors Ernst and Baum, joined in the fray commenting that there was ´no research to support B-17´, and that B-17 was used ´by a few unscrupulous practitioners across the border in Mexico´.

    1. People who have looked into this subject in depth (like Ralph Moss and Phillip Day) will tell you that there are at least five studies (three on animals, two with humans) that show some effect on cancer with B-17. But the fact is that the evidence base is poor. Very poor. There is no accepted placebo-controlled, randomised clinical trial data whatsoever with humans, although Moss (who was a science writer working in the press office at Memorial Sloan Kettering when they did conduct serious research), will tell you that the results were good  (B-17 was shown to stop help prevent cancer, stop metastases and clinical trials were recommended), but he watched as people suppressed them (Click Link for You Tube trailer)

    2. Treating people with Metabolic Therapy is not the same as giving them B-17. The world famous Oasis of Hope clinic in Mexico uses a variety of therapies including radiotherapy and chemotherapy. And it does use synthetic ´vitamin´ B-17 as a part of a package called Metabolic Therapy, which may also include pancreatic enzymes, ozone therapy, Intravenous Vitamin C and more. Does it work, and if so which bit? Although there is clearly a lot of anecdotal evidence, and I have talked at length with Contreras, himself, no overall report or rigorous data seems to exist for Metabolic Therapy either, sorry.

    3. The owners of the Oasis of Hope have not been chased out of America, nor are they ´unscrupulous´. Dr Francisco Contreras M.D., the son of the founder Dr Ernesto Contreras, and his hospital are in Mexico ... because they are Mexican. The Oasis of Hope advertises in America perfectly legally, and Americans travel to the clinic in Mexico, just as they might go to one in Chicago.
    By April 14th the UK Food Standards Agency was getting in on the act. UK newspapers published warnings issued by the FSA thus: ´Cancer patients should be aware that Apricot Kernels - a suggested cure for the disease - can kill them´. Apparently, ´Reports from overseas say eating 20-30 could result in very serious health effects´.

    Note: None of the articles specified the origin and the detail of these ´overseas reports´. There was absolutely no evidence for these claims.

    The FSA suggested that 1-2 pips per day was a safe intake. One article went on to add, ´Bitter apricot pips are thought to contain high levels of B-17, known as laetrile (sic) - described as an immune system booster and even as a cancer treatment´.

    4. Bitter apricot pips contain amygdalin, not laetrile.
     
    Few people seem to grasp the difference but it is important:

            (i) Apricot Kernels can contain up to 3 per cent of Amygdalin which is the natural form of B-17. If you chew a pip it tastes rather like old-fashioned marzipan. Eating apricot kernels does not require any medical approvals - nor should it any more than eating oranges or beetroot.

            (ii) Laetrile is something quite different - it is a synthetically prepared form of B-17 and is thus a drug and is subject to drug approval. Since there are no definitive phase III clinical trials on laetrile, quite correctly it has not received FDA approval. Full stop. 

            (iii) B-17 is not a vitamin. Krebs (see below) described it as a vitamin, but there is little evidence of any vitamin properties.

            (iv) Contreras, the world´s expert on B-17, states unequivocally that he knows of no one who has ever died from eating apricot pips. He does not treat people with apricot pips and it matters not to him whether they help or hinder. He is providing an unbiased expert opinion.

            (v) Apricot pips alone are not a cure for cancer. I know of no one who says they are. In the world. They might well perform a role in an anti-cancer complementary treatment package. Eating a few each day may also have some preventative powers.

            (vi) I also know of no one who has been treated by laetrile alone and has cured their cancer - I cannot even provide an anecdote.


    5. The problem was that B-17 (synthetic laetrile, not amygdalin) became the focus of a mighty squabble between orthodox medicine and alternative medicine.  ´Conspiracy theories´ abound in the world of alternative cancer treatments and views become entrenched. And this creates the mythology and the errors. Certain people close to the Pharmaceutical Industry then involved amygdalin, incorrectly, in the laetrile argument.
     


    Apricot Kernals and Integrative Cancer Treatment 


     
     
     
     
     
    The fact is that I personally know of a very large number of people who take apricot kernels (6 with their breakfast), and hundreds more who have used up to 50 apricot kernels a day, within a no glucose, no cows´ dairy, and an alkalising diet, as part of their Complementary and Integrative Treatment ´package´ (along with exercise etc.) when they had cancer. And the package delivered for them. Geoffrey Boycott, the former English Cricketer, would be a good example, as would Sue Olifent, who will tell her story on ´Health Academy Live´ .  Sue had liver and pancreatic cancer and the doctors sent her home because there was nothing they could do for her. 6 months later and the tumours are scars. She has set up a Support group, Active Cancer Support (Click Here), to help people find out more.

    Now, there are You Tube videos often along the lines of ´I beat cancer with vitamin B 17´. By all means watch them - e.g Sandi Rog. But you will find they almost all confuse what I have been saying above. That doesn´t detract from their belief that B-17 helped them beat cancer, of course.
     
    B-17: The basics

    6. You can crack open an apricot nut shell today in the UK - but it is against the law to treat someone with laetrile.

            a) Apricot Kernels, seeds, pips, whatever you want to call them, contain amygdalin and this is a nitriloside. A large number of bioactive compounds are provided by nature (e.g. carotenoids, phenols, anthocyanins, vitamin D, curcumin, resveratrol etc.) which can protect and correct illness; nitrilosides are one. Salvestrols (developed by Professors Potter and Burke) act similarly. Interestingly, Salvestrols (click link)  and amygdalin should not be taken simultaneously as they can contra-indicate.


            b) Laetrile (the synthetic form of B-17) can be obtained in tablet form (500 mg units) for home consumption, but is more usually administered intravenously.


            c) Laetrile prescription is illegal in the UK. No practitioner in the UK has been allowed to prescribe or use synthetic B-17 since June 2004. It has been banned since 1963 in the USA by the FDA; however, some Naturopathic practitioners in the USA seem prepared to sell laetrile to patients; and you can even buy it on Amazon!
     
    Open quotes I know of no-one who claims that either Apricot Kernels, or synthetic
                                                     B-17 (laetrile) is a cancer ´cure´, on its own
    .Close quotes
     
             d) A cure for cancer? The word ´cure´, in my experience, is only ever used by the press, or by dubious websites and ´experts´ who don´t really understand cancer. These may be staunch advocates of alternative therapies, or Skeptic twaddle sites. Neither is helpful to the cancer patient.








    Cancer is a multi-step process. There may be as many as 20 steps (according to John Boik of the MD Anderson Cancer Center in Texas). In my book, ´The Rainbow Diet - and how it can help you beat cancer´,

    I have assigned bioactive foods and natural compounds to each of the steps, but only where there is scientific research that they have an anti-cancer step activity. I know of no single natural compound that is active against all 20 steps.
    No drug cures all cancers, all of the time. There is no drug known to man that kills cancer stem cells at the heart of cancers. Why expect it, or claim it for a vitamin, or B-17?

            e) All drugs have side-effects. Those of Tamoxifen are well documented. The lack of proper research on synthetic B-17 (laetrile) has meant no safety measurements really exist. Death claims are twaddle.

    Eating too many Apricot Kernels, or too much beetroot, or too much Asparagus, or drinking too much water will cause negative effects in the body. Amygdalin does cause problems if the liver is impaired; and according to the US Nutrition Almanac you should never eat more than 6 in a 90 minute period, and the maximum in 24 hours is 35. Some people I know use 50 a day as part of their anti-cancer diet package. See below for liver concerns.

    So from this point on, when reading this article, at least put synthetic B-17 (laetrile) and Apricot Kernels (amygdalin) into a proper and separate perspective.

    For more up-to-date information on Laetrile and Metabolic Therapy, you could contact the oracle, Dr Contreras at the Oasis of Hope.

    For more on the role of Nitrilosides in treating cases of Sickle Cell Anaemia (Click Here).

    Natural B-17: A group of compounds

    Open quotesEvery area of the world supporting vegetation has such plantsClose quotes
    B-17, or amygdalin, is a naturally occurring compound. In fact it is slightly wrong to think of it as a single entity like, say, vitamin C. There is a group of approximately 14 compounds that are water-soluble and found naturally in over 1,200 species of plant in the world. Every area of the world supporting vegetation has such plants.

    The active ingredients are often described as nitrilosides or beta-cyanogenetic glucosides and there are at least 800 foods common in worldwide diets that are nitrilosidic.



    Nitrilosidic foods include:
    • alfalfa sprouts, bamboo shoots, mung bean sprouts
    • barley, buckwheat, maize, millet, sorghum
    • blackberries, currants, cassava, cranberries, gooseberries, chokeberries
    • loganberries, quince, raspberries, strawberries, yams
    • brown rice, fava beans, lentils and many pulses like kidney beans, lima beans and field beans
    • flaxseed/linseed
    • pecans, macadamia nuts, cashews, walnuts, almonds
    • watercress, sweet potato
    • the seeds/pips of lemons, limes, cherries, apples, apricots, prunes, plums and pears.
    In fact, all the foods we don´t eat too much of these days!!
    The consumption of barley, buckwheat and millet have given way to refined wheats, while pulses like lentils, which accounted for 30 per cent of our protein in 1900, now account for only 2 per cent.

    Primitive tribes around the world still base their diets around B-17-rich foods. Cassava, papaya, yam, sweet potato in the tropics; unrefined rice in the Far East; seeds and nuts in the Himalayas; the salmon-berry eaten by Eskimos, or the arrowgrass of the arctic tundra feeding the caribou.

    B-17: Its place in nature

    Open quotesThis absence of cancer seemed to be due to the difference of nutritionClose quotes
     
    Nutritionist and scientists alike studied the various tribes. Sir Robert McCarrison in the 1920s and John Dark M.D. twenty years later failed to find a single case of cancer amongst the Hunzas, the tribes of West Pakistan. V Steffanson found the same with the Eskimos and wrote "Cancer: Disease of Civilisation" as a result. Dr. M Navarro of Santo Thomas, University of Manilla, noticed the same with the Philippine population who ate cassava, wild rice, wild beans, berries and fruits of all kinds. Dr. Albert Schweitzer noted the same in Gabon. ´This absence of cancer seemed to be due to the difference of nutrition in the natives compared to the Europeans. Their diet was centred around sorghum, cassava, millet and maize´.
    Studies of the consumption of B-17 varied from Dark´s finding that the Hunzas consumed at least 150-250mgs per day, to Dean Burke, head of the cytochemistry department of the National Cancer Institute in the USA in the seventies writing that the Modoc Indians in North America consumed over 8,000 mgs per day! (Dean Burke actually gave amygdalin the name B-17).

    We leave these foods aside at our peril. The World Health Organisation has, after all, confirmed that in their view a large percentage of all cancers could be prevented by simple changes in diet.

    B-17 as a cancer treatment?

    Amygdalin was first isolated in 1830 and used as an anti-cancer agent in Russia as early as 1845.
    But it was reborn by the father/son team Ernst Krebs senior and junior by 1955 had who isolated a purified form of the active ingredient (calling it laetrile) and, with others in the late fifties to seventies, sought to explain its action.

    B-17: A seek and destroy missile?

    Cancer cells differ in a number of ways from normal cells. One major difference is the way in which they produce their energy. In a healthy cell fuel is prepared in the cytoplasm of the cell, and then moved into the mitochondria or power stations to generate energy in the presence of oxygen. But cancer cells have lost their mitochondrial action and only the preparation process remains. This is modified and demands large quantities of glucose which burn in the cytoplasm in the absence of oxygen. Cancer cells have a whole different energy production system and different set of helper chemicals (enzymes).

    Open quotes B-17 is a seek and destroy missile Close quotes
     
    In a cancer cell, one of these enzymes, glucosidase, is present at 3000 times the level found in normal, healthy cells. Glucosidase has a unique action with B-17, breaking it down into hydrogen cyanide (which kills it) and benzaldehyde, (an analgesic).

    However, in normal cells where glucosidase is virtually non-existent, a completely different enzyme, rhodenase which is involved in the normal oxygen burning process, actually renders the B-17 harmless, converting it to thiocyanate, a substance which helps the body regulate blood pressure, and vitamin B-12. So, the proponents argue, B-17 is a seek and destroy missile.

    "I have read B-17 is dangerous - it contains cyanide"

    As we explained above - the B-17 molecule, if broken a certain way, can produce cyanide. But the main enzyme that can do this is really only found in a cancer cell.

    Also, frankly, it is rather a daft argument; rather like saying the glucose molecule contains carbon monoxide and that can kill you!

    Skepti-twaddle about B-17 often refers to people dying of B-17 and cyanide but Contreras, who treats more people with B-17 than probably all other doctors in the world added together, knows of no cases.

    Then there is the fact that ´containing cyanide´ could be claimed for many food groups (for example, isothiocyanates, or anthocyanins). These food groups actually play important roles in your health, including in cancer prevention.

    Next, doctors regularly inject vitamin B-12 to enhance energy levels; you can buy vitamin B-12 on the high street. This common form is cyano-cobalmine. A layman might tell you this ´contains´ cyanide in the same way, too.

    Vitamin B-12 is involved in over 300 enzymatic reactions in the healthy body, a deficiency is known to be linked to increased cancer risk. The more natural form of vitamin B-12 is methyl-cobalmine. If a compound containing cyanide is so bad, what is the medical profession doing it injecting it into lethargic pop stars and athletes?? If it contains cyanide and that is dangerous, why don´t doctors use the methyl version?

    Nobody in their right mind would tell you not to consume B-12. So, steer clear of anyone who uses this palpably ignorant argument against B-17.

    B-17: Why the controversy?

    The use of synthetic B-17 is controversial because of conspiracy theories. It is a Skeptic versus Skeptic argument. The Skeptics against B-17 scream ´quackery´; the skeptics for B-17 scream ´cover up´:
    The Federal Drug Administration (FDA) in the USA has not approved laetrile - the FDA state, correctly, that laetrile (not amygdalin or B-17) is a synthetic therapy and, as such, needs approval like any drug. There are no randomised, controlled phase III clinical trials on laetrile so it is definitely not going to be approved. Yet people around the world do prescribe and use it. QED, they must be quacks. That´s the official view. It was actually banned in 1963, although the FDA reported that it had harmed nobody and they also said it didn´t work!

    But a core question is why has the same US Government Health Authority, the FDA, moved to ban the interstate shipments of apricot kernels and the planting of bitter almond trees? Trying to control a natural bioactive compound that logically might have some preventative benefits fuels the conspiracy theories! I noticed that my mother´s Asda "iced log" (a cake) contained 11 per cent apricot kernel paste! Presumably this cannot be moved between California and Nevada!

    One skeptic argument runs ´If eating apricot pips could cure cancer, drug companies and major cancer charities would go out of business immediately´. Actually, these businesses need not panic.

    Let us look at the ´research´ issue ...

    B-17: Any specific research?

    Open quotesThree quarters of 80 cancer test patients had seen their cancer tumours go or reduce in sizeClose quotes
    Well yes, actually there has been some research - but not much. Ralph Moss and Phillip Day seem to be the experts here and they both record that there have been three animal studies and two human studies.

    Following the Krebs´ work in 1955 a Senate Committee (often accused of being biased presumably because of drug industry connections) seemed unimpressed by evidence presented that three quarters of 80 cancer test patients had seen their cancer tumours go or reduce in size.

    There was a stab at a clinical trial in the USA and this officially reported no effect with B-17. Moss was the Press officer in the team and showed his disgust at the public hearing, implying that the team had actually found a positive response and the powers that be were mis-representing the findings. He was fired.

    However, talk to the experts that use B-17 and they will tell you that researching B-17 in a clinical trial is not the issue anyway. None doubts its efficacy, but several felt it was not as potent as other ingredients such as Intravenous, high dose vitamin C. ´B-17 only ´helps´ and is not a ´cure´ per se´, seems to be the general viewThe issue, they argue, is to research the whole ´metabolic therapy´ package. The authorities have never done this. The people who use and advocate it simply cannot afford to conduct a full scale clinical trial. Impasse.

    Why might it be more important to research the whole package? Cancers are clever and often form protective protein coats around the tumour to ward off the immune system. Various cancer clinics have thus developed their metabolic therapy packages to counter defences like these (metabolic therapy packages can contain bromelain, from pineapple and papain, from papaya, because they supposedly break down the protein coat). Other unique factors occur with cancer cells, so the metabolic therapy package may contain vitamins A, E and B complex, plus high dose intravenous vitamin C, high dose minerals, and pancreatic enzymes, each targeting a specific issue.

    The difficulty then becomes "which bit worked?"
    Having personally talked to leading B-17 practitioners in the USA and Europe, a few actually answer, ´who cares!´? Actually, I do.

    Frankly, this is quite important but the answers are unsatisfactory if you are a cancer patient. On different pages we have reviewed the use of intravenous vitamin C megadoses and pancreatic enzyme treatment as used by Dr Gonzalez in his clinic in New York. They do seem to have, albeit limited, effects on their own, so I suppose it is possible that using all of them could have a greater effect. But, be clear, there is NO FORMAL RESEARCH on the metabolic therapy package and in reality it doesn´t even exist as different clinics use different concoctions.

    Open quotesMetabolic therapy packages could be working in several ways,   but there´s no researchClose quotes
     
    Finally, laetrile has shown effectiveness against cancer cells in vitro, and in rats and mice. Interestingly, even the National Cancer Institute in America (which is negative about laetrile´s abilities), reports that by the late seventies over 70,000 cancer patients had been treated with laetrile and that there are copious individual case histories on its effectiveness. (Notwithstanding this, modern medicine demands a phase III clinical trial and there is none).
    Krebs recommended eating ten apricot seeds per day for life (the seeds or kernels of apricots have the highest levels of B-17; up to 3 per cent); cancer treatments use four to six 500mg tablets of laetrile per day or intravenous injections.

    B-17: Can it kill me?

    While there may not actually have been deaths from synthetic B-17 use, there is definitely an issue with overdosing.  If you take excess B-17 beware; cyanide by-products have been known to build up in the liver of cancer patients. Each of us has different capacities to deal with such by-products but a cancer patient has an already impaired liver. A healthy liver has an enzyme, glucorinide that can detox the by-products, but in a cancer patient, this enzyme may be depleted. So, cyanide poisoning can result if excess is consumed. 1gm is the maximum recommended to be taken at any one time.
    With the natural form of B-17, the US Nutrition Almanac recommends a maximum of 35 seeds per day; no more than five kernels at any one time in a 90 minute period. And they conclude that all cancer treatments using B-17 (synthetic, natural, or apricot kernels) should be properly supervised. Certainly, I have seen several prostate cancer patients who looked decidedly yellow all because they were trying to consume 50 kernels for breakfast!

    B-17: Subjectivity and objectivity

    As readers know, I travel the world giving speeches on cancer. I have interviewed a number of the world´s experts who use B-17 and metabolic therapy, including ´The Mexicans´, although maybe I met the wrong ones as these certainly were not unscrupulous!
    I will say that on a totally subjective note:

    a) I have seen many people, especially men with prostate cancer, who claim Apricot Kernels are the single reason their PSA scores have reduced.


    b) Contreras himself claims that metabolic therapy can ´have a significant effect´ on some cancers - though not all. He is quite clear that there is no effect with Brain Tumours, Liver Cancer or Sarcomas.

    Open quotesI have seen overdosing with my own eyes. Be very, very careful.Close quotes

    c) As I said above, I have seen overdosing with my own eyes. Both men in their 60´s, both prostate cancer sufferers and both trying to eat 50 Apricot Kernels for breakfast. Both had gone a sort of yellowish-grey. Be very, very careful.

    To repeat:

    * Never take more than 5 in a 90 minute period.


    * Never take more than 35 per day.


    * Please tell your doctor, and have someone monitor your liver health.

    B-17: Does it work in cancer treatment?

    Having read the original research on synthetic B-17 laetrile treatments and spoken to doctors and patients first hand, I find the ´evidence´ both for and against laetrile almost non-existent. I am neither an advocate, nor a critic. I just don´t know, even though I have tried to find out more.

    The logic on B-17 seems reasonably sensible and certainly pharmaceutical companies are devoting significant resources to targeting exactly the same unique properties of a cancer cell. But, as I repeatedly say, I don´t think any single entity is a ´cure´ for cancer - and that goes for B-17 too. Could it play some or other role in the total package? Experts like Contreras are adamant it can. There are people of You Tube who swear it worked for them. I´m not at all as sure. Would I pin my hopes on it alone? No. But then many of the subjects were past the point of no return - orthodox medicine had failed them.

    Open quotesB-17 - even eating too many apricot kernels - can be dangerous
                                                          if your liver is impairedClose quotes

    With Apricot Kernels, and amygdalin, for me there is a different issue. I believe everybody should include nitriloside foods in their daily diet. I put five - six kernels with my home-made breakfast each morning, but then I eat copious amounts of food off the B-17 list above anyway. Personally, I believe there is a good prevention argument, and eating half a dozen ´apricot pips´ a day is hardly a dangerous medical issue. 

    So, B-17 "Cancer cure or quackery?"
    The Bottom Line
    There is a good argument for including apricot kernels in your anti-cancer programme as a preventative bioactive compound.

    However, no one has ever approached me and told me that eating 50 apricot kernels a day alone ´cured´ their cancer.  In fourteen years not one person has so much as come up to me on my worldwide travels with even an anecdote.

    However, many, many people I know have used them (35-50) as part of their anti-cancer treatment package (most often diet-based) and the package worked. Also there are You Tubes of people who beat cancer this way.

    And what of Laetrile - synthetic B-17  - as an out and out cancer ´cure´? I don´t think so. Those that use it don´t rely on it on its own. And do I have reports of Laetrile ´curing´ cancer in the last ten years? Is there any new research? No, none. Even the You Tube videos are often confusing as to whether the laetrile was taken on its own or with other compounds that could also have helped. Again, with this in mind, go and watch the videos.


         

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    And so we have compiled a Rainbow Diet research Centre. There are a lot of research studies in it! Not just on cancer, but on Alzheimer´s, diabetes, cardiovascular disease, Parkinson´s, strokes and much, much more.
    Go To: The Rainbow Diet Research Centre - latest news 
    If you want to buy the book - Please Note - we do not supply retailers, for example, Amazon. The CHEAPEST way of buying the Rainbow Diet book, and Rainbow Recipes is direct - through our Charity Distributors ... ...
    Go HERE to: BUY NOW at CHEAPEST PRICES: (USA/Canada, Australia, Europe).
    2. The Diet book above all others

    Some people think a Rainbow Diet is just about eating lots of colourful vegetables and fruits. WRONG!! Lots of fruit can give cancer patients too much sugar, and this simplicity also ignores the role that fats and carbohydrates play in cancer, heart disease and other chronic illnesses. For example, while there is clear research that ´bad fat´ consumption is NOT linked to increased cardiovascular risk, there is clear research that it can HELP CANCER SPREAD.   And therefore this book is not just about the colourful Mediterranean diet. It reviews the research facts on food and many of the supposed anti-cancer diets in an easy to understand way, to help people build a cancer diet that can help prevent, and also correct. The book even includes a practical ´shopping list´. 
     "I´ve been involved with health and healing issues for nearly forty years.  Every word of Chris´s book rang true, and I´m convinced that the ideas in it are a powerful and effective way to optimum health. Anyone suffering from ill health or disease will find it a life-enhancing experience." (British actor, and natural health follower, Martin Shaw)

    Chris Woollams, who compiled the book for CANCERactive says, ´More than a decade of study and all the research from Harvard, UCLA and other top medical centres has gone into the latest updated edition of ´The Rainbow Diet - and how it can help you beat cancer´. In the book I look at the research available on various cancer prevention diets, and then I look into their relevance if you already have cancer. But don´t forget the French Paradox - it´s the ingredient the Health Authorities have ignored for 35 years but it´s the clue to better health; or the new science of Epigentics, providing solid research that natural compounds can correct diseases like cancer. 
    *** BUY HERE: CHEAPER THAN AMAZON : Order the Rainbow Diet, NOW!! ***
    3. What can I do to help my diet, starting today?
       This book tells you:

    * What you can do about your diet - starting today
       * Why other diets fall short - and you are wasting your time with them
       * How carbohydrates may be damaging your health
       * How good fat can help fight illness and cancer
       * Which bad fats you must avoid or they could spread cancer
       * The Truth about dark chocolate, red wine, coffee and soy
       * Which bioactive natural compounds can you add to your diet to actively fight cancer
       * Which minerals are helpful and which feed cancer
       * How lifestyle factors like sunshine and exercise interact with your diet
       * How to control inflammation in your body
       * Which natural compounds in which foods best boost your immune system
       * Which compounds in which foods can actually improve the success of radiotherapy and chemotherapy
       * Natural herbs that fight yeast and fungal infections in real life
       * A shopping list to take with you when you go out!





     You can change your life today; you can build the ´new you´.  This book gives you the answers and much, much more´.
      Cheapest Prices Guaranteed: Order your copy of The Rainbow Diet in the UK, America, Australia NOW!


    GO to:  RAINBOW RECIPES, the book
    GO to: Rainbow Diet Research Centre  


     If you are thinking of buying Apricot Kernels, you might like to see what is available as the Natural Selection Product of Choice. You can do this by clicking here.