Aloe Vera
Part
2
In
this section I will be looking at the plant itself, and its application in wound
care, burns and its antimicrobial effects. There is a lot of research that has
been undertaken and much of it contradicts the other though I have the suspicion
that the views taken have a bias to take into consideration depending on whom
they are working for and what their outlook is on alternative therapies. Though
this could be my bias. I will let you decide. I hope you don’t find the
science too boring though for me it is needed to make an informed decision about
this herb.
There
are about 200 species of aloe, but aloe vera, meaning true aloe in Latin, is
considered the most effective healer. The Aloe originates from tropical Africa,
where related species are used as an antidote to poison arrow wounds. The
aloe plant is the source of two products used for different therapeutic
purposes. Most uses of aloe refer to the clear
gel inside its cactus-like leaves. However, the skin of the leaves themselves
can be condensed to form a sticky yellow substance known as drug aloe, aloe
latex or aloes.
Aloe gel is used both externally and internally for its wound-healing properties
and as a general tonic or cure-all plus it is
used extensively in cosmetics and skin creams. Aloe gel is regarded as one of
nature's best natural moisturizers. The Aloe
latex or juice, is bitter and extracted for
medicinal use, usually
in its dried form, and is used as a potent laxative though
an unpleasant one though this will be discussed more in Part 3.
Fresh
Plant or Product?
The
gel comprises more than seventy-five compounds, including polysaccharides
(complex carbohydrates), steroids, organic acids, enzymes, antibiotic agents,
amino acids, and minerals. One enzyme found in aloe gel has been suggested as
the primary component responsible for the gel's ability to heal burns. So we
know that Aloe Vera is potentially an all round healer and supplier of vital
ingredients for life. SO here comes the first of the divisions concerning this
herb. Although the majority of sources agree that the gel possesses healing
properties in its
fresh state, there is controversy over whether this activity is retained during
storage as it oxidises on contact with air. One site (http://www.herbs2000.com) suggests the following:
Commercial processors claim that the stability problem has been overcome, and a
"stabilized" product is incorporated in a wide variety of
preparations, including juices, gels, ointments, creams, lotions, and shampoos.
However, at least one scientific test failed to verify any beneficial effects of
a "stabilized" aloe vera gel on human cells. Fluid from fresh leaf
sources was found to promote significantly the attachment and growth of normal
human cells grown in artificial culture. It also enhanced the healing of wounded
monolayers of the cells. The "stabilized" commercial product, however,
not only failed to induce such effects but also was proved to be toxic to the
cultured cells. The investigators who carried out these studies concluded that
commercially prepared aloe vera gel fractions "can markedly disrupt the in
vitro attachment and growth of human cells." This was one report and I
could not find any other sources that reiterated this. In fact other sources
contradicted this stating that a review of several other studies led to the
conclusion that a number of them did provide evidence to support the use of aloe
vera gel, and some preparations containing it, for the treatment of various
types of skin ulceration in humans and burn and frost bite injuries in animals.
More recently, a cream base containing aloe was found effective in preserving
circulation in the skin after frostbite injury. Stabilized aloe vera was shown
to produce a dramatic acceleration of wound healing in patients who had
undergone full-face dermabrasion. However, most agree that many compounds of
aloe are probably subject to deterioration on storage, so use of the fresh gel
is the only way to be certain of maximal activity where long term storage is
likely. The next problem highlighted was that
many so-called aloe vera preparations on the market contain very little of the
plant. Some state "aloe extract" or "reconstituted aloe vera",
which are watered down versions not too beneficial. A true aloe product will
list aloe vera as a primary ingredient and usually state that it is 97% to 99%
pure aloe vera.
Also,
the mechanical separation processes employed to separate gel from the aloe latex
are often not completely effective. As such, aloe gel is sometimes contaminated
with aloe latex, thus inducing an unwanted purgative and bitter effect on wounds
and can cause problems with healing though this will be mentioned later.
To
confuse matters even more thoroughly, there is still another product called aloe
that is entirely different from the two just described. That is the aloe of the
Bible, the so-called lignaloes or aloe wood, a fragrant wood from an entirely
different plant that was once used as incense. It has nothing to do with the
aloe we are discussing except that some persons try to glamorise aloe gel by
incorrectly ascribing to it a biblical origin. The names may be the same, but
the plants referred to are not.
The
fresh leaves of the aloe can be split to expose the gelatinous juice and then
rubbed on the skin for sunburn, wrinkles, headache, insect bites, skin
irritations, and minor cuts, ulcers, sores, herpes, jaundice, bursitis, canker
sores, sore gums, and scratches. The fresh juice is also said to help heal
wounds by preventing or drawing out infection, and for poison ivy. Rub the scalp
with aloe and it keeps the hair from falling out. A tea made from the dried
juice makes a good wash for wounds and for the eyes.
Wound
Healing (Vulnerary)
Extensive
research since the 1930s in the US and Russia has shown that the clear gel has a
dramatic ability to heal wounds, ulcers, and burns, putting a protective coat on
the affected area and speeding up the rate of healing. This action is in part
due to the presence of aloectin B, which stimulates the immune system. It is
proposed that aloe works by inhibiting bradykinin, a pain-producing agent; also,
it apparently hinders the formation of thromboxane, whose activity is
detrimental to burn wound healing (see also frostbite). Aloe gel also has
antibacterial and antifungal properties. A glycoprotein fraction has been shown
to promote cell growth in human and animal cell media. Aloe
vera contains Glucomannan, a special complex polysaccharide composed largely of
the sugar mannose. It interacts with special cell-surface receptors on those
cells which repair damaged tissues, called fibroblasts, stimulating them,
activating their faster growth and replication. Plant hormones in Aloe, called
gibberellins, also accelerate healing by stimulating cell replication. Nevertheless,
it is still considered that relatively little is known about the identity and
stability of the ingredients responsible for these effects and research is
ongoing to isolate the factors.
A
study published in the Journal of Dermatologic Surgery and Oncology (cited on http://www.askdrhelen.com/hl_Aloe_Vera.html)
revealed that aloe decrease surgical recovery time. According to Dr. Fulton,
"any wound we treat, whether it's suturing a cut or removing a skin cancer,
heals better with aloe vera on it." Patients’ wounds were dressed with
aloe Vera gel and healed approximately 72 hours (3 days) faster than wounds that
were dressed with surgical gel only. Another study published in the Journal of
the American Podiatric Medical Association found that both oral and topical aloe
preparations speed wound healing. In fact, the oral aloe decreased the size of
wounds by 62% and the gel produced a 51% decrease in wound size compared to 33%
in the control group. All this sounds very promising but, yeah there’s a but,
one clinical report suggests that aloe can actually impair the healing of severe
wounds (http://healthinfo.healthgate.com).
This research was reviewed and questioned by Blanchard: “Schmidt and
Greenspoon (1991) conducted a clinical study to determine the effect of Aloe
vera dermal wound gel on the healing rate of surgical wounds in obstetric and
gynaecology patients, requiring healing by second intention. It became evident
that the use of Aloe vera dermal wound gel was associated with a significant
delay in wound healing, and consequently the study was terminated. The internal
validity of this study was compromised by a number of factors. Firstly, there
were significantly more dropouts in the standard treatment group (60%) compared
to the Aloe Vera treated group (35%), which leads to mortality effects.
Experimenter and participant bias was present because a placebo gel was not
available to use for a double blind study. Also, selection bias must be
considered, as all of the treated wounds were different sizes and depths at the
outset. Another weakness of this study was that the authors did not address any
possible alternative explanations for the findings. For example, they informed
us that the Carrington Aloe Vera dermal wound gel contained Aloe Vera, but not
how much, and what else was in the gel that may have contributed to decreased
healing rates? The authors commented that the visual appearance of Aloe Vera
treated wounds was distinctly different from that of wounds treated by standard
protocol. The granulation tissue initially developed lush and bright red in
colour. However, within a few weeks, the granulation tissue became pale and
fibrotic compared to the control wounds. This may suggest that any stimulatory
effects of Aloe Vera on wound healing could be short lived and possibly
counter-productive after a period of time.” (http://podiatry...encyclopedia.../). Scientific evidence
that refutes this can be found in the work of Fulton
(1990) which concluded that Overall, wound healing was
approximately 72 hours faster when a dermabrasion site was treated with an aloe
dressing when compared to the standard dressing. This acceleration in wound
healing is important to reduce bacterial contamination, subsequent keloid
formation, and/or pigmentary changes; the 1994 work by Udupa
et al who observed that there was a significant increase in breaking strength
(skin and granuloma tissue), enhanced wound contraction and decreased
epithelisation period; and numerous research undertaken by Heggers et al which
you will read through out this text. (The full references can be found at http://www.lef.org/...abstracts..). This is but to quote
but a few of the findings that have been published.
Bactericidal
studies
Various percentages of Aloe Vera gels were tested in culture media consisting of
the following organisms: Staphylococcus aureus, Streptococcus viridans,
Candida albicans, Corynebacterium xerosis, and the five strains of Streptococcus
mutans most commonly found in dental plaque. The gel was bactericidal
against the above bacteria and fungicidal against Candida albicans (the
cause of moniliasis or 'denture sore mouth.') An important finding by Zimmerman
was that the dramatic effects of the Aloe gel were not apparent until there was
at least a 70% concentration of the gel. To achieve a 70% or greater
concentration, an Aloe Vera gel must be stabilized with anti-oxidants in order
to minimize the otherwise necessary preservatives that lessen the percentages of
Aloe Vera in the product. (http://www.aloenieuwsbrief.nl/....)
Virucidal studies
The Aloe Vera gel formula was found to be virucidal against Herpes simplex and
Herpes zoster viruses.
Anti-inflammatory studies
Prednisolone and Indomethacin (common anti-inflammatory drugs) were utilized in
a comparative study with the Aloe Vera gel to observe the effects on tissue
culture cells. The gel was found to be just as effective as Prednisolone and
Indomethacin, without having the long term toxicity of either drug. Along its
other healing ingredients, aloe vera contains salicylic acid, which is the main
content of aspirin. The salicylic acid and magnesium in aloe are thought to work
together for an analgesic effect on burns. It was used in 1935 to treat
third-degree x-ray burns, and more modern medicine uses it to treat atomic
radiation burns. Applied to wounds, the gel not only reduces pain and infection,
it stimulates cell regeneration and therefore the growth of new tissue and skin.
Scarring can be reduced significantly by using aloe vera. Aloe had shown
outstanding results in treating facial oedema (swelling).
Dr.
Robert H. Davis, a physiologist at the University of Pennsylvania College of
Podiatric Medicine, has conducted research on aloe vera since the early '70s.
Results of laboratory tests on animals indicate that aloe vera can prevent and
arrest arthritis, improve wound healing, inhibit pain, block inflammation,
restore bone growth, and act as a vehicle for the delivery of nutrients to the
body. Dr. Davis stated, "Aloe vera contains the greatest number of active
substances of any plant I've looked at." (http://www.holisticbirds.com/..)
Burns
Aloe
gel is a common household remedy for minor cuts and burns as well as sunburns.
In the last twenty years, a plethora of published scientific research has given
weight to the appropriateness to use aloe vera in treating minor wounds and
burns which up to then had been based on anecdotal evidence.
A review of
the medical literature by a group at the University of Texas in Galveston
concluded that aloe gel clearly promotes wound healing and prevents progressive
skin damage caused by burns and frostbite. It works by penetrating injured
tissue, relieving pain, reducing inflammation, and dilating capillaries to
increase blood flow to the injury. Aloe
gel contains active substances known as glycoproteins and polysaccharides.
Glycoproteins are protein-carbohydrate compounds that speed the healing process
by stopping pain and inflammation. Polysaccharides are a type of carbohydrate
that stimulates skin growth and repair. These substances are also thought to
stimulate the immune system. Aloe contains active compounds that stop pain and
inflammation and stimulate skin growth and repair. This all sounds great but the
research quoted on various sites conflicts as to the value of aloe vera in the
field of wound and burn care.
Having
waded through numerous sources, I would appear that the findings alternate
through the years, first proving the benefits and then announcing detrimental
or no active benefits before more positive findings are announced again.
Unfortunately, papers are happy to quote and continue to quote negative findings
from one off trials, even if they have been questioned as valid, where as
positive research is derided as too small or suggest further research is
required. The negative research quotes that scientific evidence fails to support
this belief.
Some
studies suggest that aloe is not effective for treating sunburn and may actually
impair the healing of second degree/partial thickness burns (http://healthinfo.healthgate.com).
This research is questioned by Elizabeth Blanchard (http://podiatry....encyclopedia../) who states the
following: “Kaufman et al (1988) carried out a study titled "Aloe Vera
Gel Hindered Wound Healing of Experimental Second-Degree Burns". The aim of
the study was to determine the effectiveness of Aloe Vera gel on burn wound
healing compared to silver sulfadiazine (AgSD) cream. They found that AgSD
treated wounds had higher epithelialization rates, while Aloe Vera gel treated
wounds had higher wound contraction rates. The fact that this study did not have
a control group that received no treatment indicates that the title of this
study is misleading. For the authors could not prove that Aloe vera gel hindered
burn healing, but that burns treated with Aloe Vera gel did not seem to heal as
fast as burns treated with AgSD cream. The research question of this study was
not clear and did not fully encompass the experiment. In addition to this, the
wound measurement tool was not validated, and a relatively small sample size was
used (14 subjects). There was a problem with the Aloe Vera gel itself (as
acknowledged by the authors). The gel used was a crude extract from the plant
and no description was given as to exactly how it was prepared. This would make
the study very difficult to reproduce. The authors tired to explain that local
infection might have contributed to the impairment of epithelialization in the
Aloe Vera treated wounds.” Compare this research, for the moment at face
value, with the research that follows.
Alternately,
research undertaken by John Heggars, M.D., (Chicago Burn Center) demonstrated
the ability of the Aloe Vera to heal third degree burns and frost bite up to six
times faster than accepted modern medical treatment. A
study published in the Annals of Emergency Medicine (Heggers et al (same
researcher as Heggars?)1987), established that aloe Vera works for frostbite as
well. Researchers gave standard treatments for frostbite (antibiotics,
ibuprofen, and rewarming) to 154 patients with mild to severe frostbite. Of
patients who additionally received aloe Vera gel, 67.9% healed without any
tissue loss (amputation) compared to 32.7% in the control group. Researchers in
1993, concluded that aloe prevented a decrease of blood flow to the frozen
tissues, a common cause of tissue loss in frostbite and also stopped thromboxane
cascade that causes further damage and death to the cells as mentioned above.
This research combined with others, forms the rationale for Trauma and Plastic
surgeons to propose the use of Aloe Vera gel in their protocols for the
treatment of frostbite, one of which can be found at http://www.emedicine.com/med/topic2815.htm.
The
Kauffman research suggests that infection was to blame for the detrimental
findings. Aloe vera gel has demonstrated activity against bacteria in several
studies. The antimicrobial effects against skin pathogens being slightly
superior to silver sulfadiazine, a potent antiseptic used in the treatment of
extensive burns (http://www.doctorphyto.com). Also, the research quoted
using AGSD. This is of interest when you consider that AGSD should only be used
for full thickness (3rd degree) or infected burns and not routinely
for partial thickness (2nd degree) burns. Also, AGSD should not be
used on faces as contact with light turns it black and dyes the skin where as
aloe vera has no such problem. In research by Visuthikosol
et al (1995), twenty-seven
patients with partial-thickness burns were treated with Aloe Vera Gel in a
placebo-controlled study (World Health Org Library).
The Aloe Vera Gel-treated lesions healed faster (11.8 days) than the burns
treated with petroleum jelly gauze (18.2 days), a difference that is
statistically significant (t-test, P _ 0.002). Interesting to note
when petroleum jelly gauze often known as Jelonet, is the dressing used in the
hospital setting for the treatment of partial to full thickness burns.
Dr.
Heggars (1980 – 1995 studies) concluded that healing effects were due to
steroidal like compounds, (acts like cortisone), and salicylic acid. He stated
that Aloe treatment eliminated scarring; normal skin colour returned and
unbelievably the Aloe completely regenerated the hair follicles, and allowed for
re-growth of hair in burned area. He concluded that Aloe was more effective in
preventing and controlling infections than Silver Sulfadiazine (http://www.aloe-info.nl/myth.htm)
and topical Aloe significantly enhances the rate of wound healing and when
combined with silver sulfadiazine reverses the wound retardant effect
observed with silver sulfadiazine (http://www.lef.org/...abstracts.. ). When you take the
positive research and compare it against the negative, it would appear that
without further evidence of detrimental effect, Aloe Vera has a place in burns
and wound care!
Radiation Therapy
Aloe has been used in the treatment of x-ray radiation therapy with good effect since the 1930’s and there is numerous early research that backs this up. However, modern research has argued that Aloe appears to be ineffective for treating the burn-like skin damage caused by radiation therapy for cancer (http://healthinfo.healthgate.com). In a double blind, placebo controlled study of 194 women undergoing radiation therapy for breast cancer, use of aloe gel failed to protect the skin from radiation-induced damage. Lack of benefit was also seen in an open controlled trial of 225 women. An unblinded controlled study (2001) of 75 people receiving radiation therapy for various forms of cancer found some evidence that soap enriched with Aloe Vera gel can help protect the skin from radiation damage. However, it is proposed by the above source that researchers had to use questionable statistical methods to find evidence of benefit, making the results less than fully reliable. Though looking at the results that were reported in the Oncology Nurses Forum, it would appear that this research merits further examination. A double blind, placebo-controlled study (2002) that evaluated the effects of aloe gel in 225 women undergoing radiation therapy for breast cancer found no benefit (http://healthinfo.healthgate.com). Despite this, there is on-going research into the use of Aloe in radiation injuries from x-ray, atomic or nuclear injuries. Also, balancing the above research, is the conclusions that Aloe Vera gel protects against skin damage from X rays, according to researchers at Hoshi University in Japan, published in the journal Yakugaku Zasshi. They found that aloe was an effective antioxidant, mopping up the free radicals caused by radiation, and that it protected two of the body's healing substances, superoxide dismutase (an antioxidant enzyme) and glutathione (an amino acid which stimulates the immune system)(http://www.absoluteslimming.com). Also, a review by the World Health Organization (World Health Org Library) cites Aloe Vera Gel has been effectively used in the treatment of first- and second-degree thermal burns and radiation burns. Both thermal and radiation burns healed faster with less necrosis when treated with preparations containing Aloe Vera Gel. This was drawn from work undertaken by Shelton (1991) and Haller (1990). There are other small positive trials that also support the use of aloe gel in this field. It would appear that further research into aloe on its own or in combination needs to be undertaken in this field.
Please note: any hot thermal
burn that results in more than superficial redness and small blistering, and
electrical or frostbite burns should be treated by healthcare professionals.
Aloe vera may be applied as a first aid measure.
From
all of the information above, it could be concluded that aloe vera has a
valid place in the home for treatment of wounds and burns. The concerns over
healing would appear to be in long term use and this alone is a one off study
that would need more investigation where as the pro’s for this herb appear to
be far more numerous and conclusive. But you must make your own mind up.
In
the next part, other skin conditions, dentistry and other uses will be looked
at. Also aloe latex will be discussed.
