Honey for the Treatment of Infections


by Dr. Molan, University of Waikato, New Zealand 

An Ancient Medicine Rediscovered

Honey is one of the oldest medicines. Its use is recorded in Sumerian
clay tablets estimated to be 4,000 years old, and in Egyptian papyri
dated from 1900 to 1250 B.C. It is also mentioned in the Veda, the
sacred scriptures of Hinduism, thought to be about 5,000 years old,
and in the Holy Qu'ran and the Talmud. Hippocrates (460-357 B.C.)
used many of the Egyptian prescriptions. He found that honey "cleans
sores and ulcers of the lips, heals carbuncles and running sores." 
Celsus (circa 25 A.D.) used honey for many different purposes: as a
laxative, as a cure for diarrhea and upset stomach, for coughs and
throat maladies, to agglutinate wounds and for eye diseases.

Honey has continued to be used in medicine ever since, but little was
known about how it worked. It was not until the late 19th century that
bacteria were found to be the cause of infections. Although there are
several reports in medical journals in the 1930's of honey being effec
tive in clearing wounds of bacterial infection, it was not recognized
in these reports that it had been established in laboratory work in
1919 that honey has antibacterial activity. It was not until the
mid-1940's that more intensive laboratory studies were carried out,
but by this time antibiotics were becoming available for the treatment
of infections, and honey was displaced from use in medicine.

Despite the advent of antibiotics, honey has continued to be used in
folk medicine, and it is from this pool of knowledge that the
re-introduction of honey into modern medicine has come. There have
been numerous reports in medical journals of this folk remedy being
used as a last resort on infected wounds, burns and ulcers that were
not responding to antibiotic treatment. The remedy was in all cases
found to be remarkably effective. This effectiveness is being
recognized in an increasing number of reports. In 1989, an editorial
in the Journal of the Royal Society of Medicine expressed the opinion
that "the time has now come for conventional medicine to lift the
blinds off this 'traditional remedy' and to give it its due
recognition."

Recent Research

Many researchers have reported that honey varies in the potency of its
activity. Despite this, none of the reports in the medical journals
mentions any selection of the honey used. At the University of
Waikato we have investigated how much variation there is in the
antibacterial activity of honey likely to be used medically.
Commercial apiarists supplied 345 samples of honey from 26 different
floral sources for the study. The samples of honey were tested against
staphylococcus aureus, the most common wound-infecting species of
bacteria. The activity of each sample was compared with that of a
reference antiseptic, phenol (carbolic). It was found that the
activity varied from a level that was the equivalent of 58% phenol to
a level that was below the limit of detection (2% phenol). One third
of the samples tested were of this low level of activity. The results
of this research (recently published internationally in the Journal
of Pharmacy and Pharmacology) show the importance of selecting the
honey used for medical purposes. Although all honey will stop the
growth of bacteria because of its high sugar content, when the sugars
are diluted by body fluids this antibacterial action is lost. The
additional antibacterial components (primarily hydrogen peroxide
generated by the glucose oxidase enzyme in the honey) then become
important. Considering that carbolic disinfectant is usually used with
a phenol concentration of 4-5%, it is evident that selected honeys can
remain antibacterial when extensively diluted by body fluids.

Another finding in this research was that hydrogen peroxide was not
the only antibacterial substance involved in some types of honey. When
testing samples of the honeys with the enzyme catalase added to
remove the hydrogen peroxide, it was found that only two of the 26
floral types of honey contained significant levels of this additional
antibacterial activity. In one of these, vipers bugloss honey, the
level of activity was quite low. In the other, Manuka honey, the
additional antibacterial activity was in some samples quite high,
although it is important to note that half of the 60 samples tested
had very low levels or none of this additional antibacterial activity.

This additional antibacterial activity was considered to be important
enough to warrant further investigation. As a project for her recently
completed M.Sc. thesis, Dawn Willix compared the antibacterial
activity of an average-level Manuka honey with that of an
average-level honey with activity due to hydrogen peroxide,
testing them on seven different species of bacteria chosen as the ones
most commonly involved in wound infection. The percentage (by volume)
of each type of honey needed to completely prevent the growth of each
species of bacteria was found to be:

	               Manuka	Other
	               Honey	Honey
Escherichia coli	3.7	7.1
Proteus mirabilis	7.3	3.3
Pseudomonas aeruginosa	10.8	6.8
Salmonella typhimurium	6.0	4.1
Serratia marcescens	6.3	4.7
Staphylococcus aureus	1.8	4.9
Streptococcus pyogenes	3.6	2.6

Although some species of bacteria are more sensitive to the action of
one type of honey than they are to the other, on average there is
little difference. The most notable point is that these "average"
honeys can be diluted nearly ten-fold yet still completely halt the
growth of all the major wound-infecting species of bacteria. Also
notable is the finding that an "average" Manuka honey will still halt
staphylococcus aureus when diluted with 54 times its volume of fluid:
this is not only the most common wound-infecting species, but is
notorious for developing resistance to antibiotics.

The work has recently been carried further by microbiologists at
Waikato Hospital looking at the effect of these two honeys on their
collection of strains of MRSA--strains of staphylococcus aureus that
cause ward closures in hospitals because they are resistant to most
or all of the commonly used antibiotics. All of the strains have been
found to have their growth halted completely by the honeys diluted to
5-10%.

Similar sensitivity has been found in some other recent work, carried
out at the University of Waikato, in which we tested the bacterial
species that cause mastitis in dairy cattle. If honey is as effective
in the udder as it is in the laboratory in stopping the growth of
these bacteria, then it would be a very useful alternative to
antibiotics as it would not need the milk to be held back because of
unacceptable residues from the treatment. Injection of honey up the
teat of a cow should cause no problems when it is considered that it
can safely be put in the eye for the treatment of eye infections.

Stomach Ulcers

In the traditional medicine of some parts of the world honey has also
been used to treat dyspepsia and stomach ulcers. There are numerous
reports of this treatment being used successfully in clinics in Russia
in modern times, and a recent report of a clinical trial in Egypt
which established that this traditional remedy is in fact effective.
However, there has been no explanation of how honey works in this
treatment, which has prevented the treatment from being considered
seriously by many in the medical profession.

In the last few years it has been recognized that dyspepsia and
stomach ulcers are frequently caused by infection of the stomach
by a species of bacteria, helicobacter pylori. The possibility that
the healing effect of honey on the stomach may be through its acting
on this bacterium was suggested by Niaz Al Somai at the University of
Waikato. In collaboration with microbiologists at the Waikato Hospital
he tested strains of helicobacter pylori isolated from biopsy samples of stomach ulcers, using the same two honeys that had been tested on the wound-infecting species of bacteria. It was found that the honey with hydrogen peroxide activity did not prevent the growth of cultures of helicobacter pylori when added at concentrations up to 50%, but the Manuka honey completely halted growth of the bacterium at a concentration of 5%.

A clinical trial was organized to find out if Manuka honey has the
same effect on the bacterium in the stomach as it does when they are
on agar plates. There is much interest in this possibility because
conventional therapy for stomach ulcers is far from satisfactory.
Drugs which prevent secretion of acid in the stomach may allow an
ulcer to heal but it frequently re-appears. Only if helicobacter
pylori is eliminated is a lasting cure achieved, but it is a very
difficult infection to clear. A combination of antibiotics and bismuth
is required, and unpleasant side-effects often result.

There is also the consideration that a very large amount of money is
spent on the pharmaceuticals currently used to treat stomach ulcers.
If honey is shown by clinical trial to be a reasonable alternative it
would be a much cheaper option.

The trial was abandoned without completion because the gastroenter-
ologists were not entering sufficient patients, so no conclusive
results were obtained regarding the ability of the treatment with
Manuka honey to clear the bacterial infection. However, there was a
clear indication that the patients taking the honey with antibacterial
activity had significant relief from the discomfort and pain
associated with their illness, whereas the patients taking honey
without antibacterial activity did not. (Neither group of patients
knew whether they were taking active or inactive Manuka honey, nor did
their gastroenterologists know. The dosage used was 3/4 oz of honey
four times a day, 1 hour before meals or at bedtime.)

Update On Current Research 

This presentation is to provide an update on the current research into
the antibacterial activity of honey being carried out at Waikato
University under the direction of Dr. Peter Molan. A priority at the
present time is to provide scientific evidence of the effectiveness an
d safety of using honey as an alternative to conventional forms of
treatment for skin and gastro-intestinal infections in the medical
field and mastitis, wounds and scours in the veterinary fields. We
have numerous reports, both scientific papers and personal
communications, of honey being used successfully to treat ulcers,
bedsores, wounds, burns, and dermatitis which were not responding to
usual methods of treatment, but it has proven difficult to convince
those in the medical and veterinary professions that honey is a safe
effective remedy to use.

Sterilization of honey 

One of the main objections to using honey has been that it may
introduce a new infection from bacteria or spores present in the
honey. Although it is generally thought that honey is a sterile
product, bacteria and spores are able to survive in the honey but it
is unlikely that they will actually grow in it unless the water
content is too high. One report has shown that disease causing
bacteria introduced into honey samples were capable of surviving 1.5
months to 2.4 years at 214F. Heat treatment or filtration through
microporous membranes which are capable of preventing the passage of
bacteria and spores are the usual ways medical products are
sterilized. Sterilization of honey by heat treatment is not suitable
because any hydrogen peroxide activity would be lost, and although it
is more heat stable, there is also a reduction in the non-peroxide
activity of Manuka honey at the temperatures required to ensure
complete sterilization of honey. Filtration is also not suitable
because of the high viscosity of honey, and particles present in the
honey which block up the pores in the membranes. Gamma-irradiation,
which is used to sterilize items such as surgical gloves and dressings 
which cannot be heat sterilized, was suggested as a possible
alternative for sterilizing honey for use in hospitals. It may also be
worth considering as an alternative to heat treatment of honey which
is required when exporting to the Australian market. To determine
whether this would have any effect on the antibacterial activity of
the honey, samples were tested for activity before and after
gamma-irradiation. The results showed that there was no significant
reduction in the antibacterial activity of honeys containing hydrogen
peroxide activity and Manuka honeys with non-peroxide activity.

Clinical Trial on Wound Healing 

In conjunction with staff at Waikato Hospital a clinical trial is in
its preliminary stages using honey as a wound dressing. The aim is to
compare the effectiveness of honeys with the two different types of
activity (hydrogen peroxide, and the non-peroxide activity of Manuka
honey) and also compare these with a standard treatment. So far only
Manuka honey has been used, and good results are being obtained.

Honey for the Treatment of Gastroenteritis 

Currently, with funding by the Honey Industry Trust, a study is being
carried out to determine whether organisms which cause gastroenteritis
(diarrhea and vomiting), are sensitive to the peroxide and
non-peroxide antibacterial activity of honeys. Again many reports have
indicated that honey is an effective remedy for stomach upsets. One
report in the British Medical Journal suggested that it shortened the
duration of bacterial diarrhea and was as effective as glucose at
promoting the re-absorption of sodium and water from the intestines.
As the major problem with gastroenteritis is that the patient becomes
dehydrated, dosing with honey would help to replace lost electrolytes
and provide an energy source as well.

A pasture blend honey with a high hydrogen peroxide activity and a
Manuka honey with a medium non-peroxide activity are being compared
with an artificial honey ( a mixture of sugars at an acid pH similar
to that found in honey). The artificial honey is used as a control to
determine whether the antibacterial activity is due solely to the high
sugar and low pH of honey or to some other factors present only in the
honeys.

The results show that the organisms tested so far are inhibited by
concentrations of 5-8% pasture blend ( high peroxide ) and 7-11%
Manuka honey but it requires 20-30% artificial honey to have the same
effect, clearly showing that factors other than sugar and pH are
providing the antibacterial activity.

Although the bacteria tested so far have been isolated from human
infections the indications are that honey could be equally effective
and valuable as a remedy for scours in young animals such as calves.
It could also be used as an organic alternative to the antibiotic food 
supplement currently used for other animals including piglets and
poultry. This avoids the problem of antibiotic residues. Bacteria
isolated from animal sources will be tested in the next stage of the
study.

Effect of Honey on Fungi 

Another project recently funded by the Honey Industry Trust was to
determine whether honey had any activity against a range of
dermatophytes, i.e. fungi causing skin infections such as ringworm
and athletes foot. All the fungi species tested were inhibited by low
concentrations of the hydrogen peroxide activity but considerably
higher concentrations of Manuka type non-peroxide activity were
necessary for inhibition.

All information that appears here is reprinted in whole or in part
from the World Wide Web or other sources as noted.


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