Introduction
Oregano
(Origanum
vulgare)
is a perennial herb indigenous to Europe, Asia, and particularly the
Mediterranean. It is a member of the mint family and is closely
related to marjoram. The primary active medical ingredient in oregano
is carvacrol,
which has its highest concentration in the oil from oregano plants of
the Mediterranean.
Oregano
has been used since ancient times to treat medical
ailments, Wikipedia
reports that Hippocrates used oregano as an antiseptic, as
well as a cure for stomach and respiratory ailments.
Several scientific studies have been published
that have investigated oregano and carvacrol. Most of the studies
report research that was done on animals or cell lines, but there are
a few that researched directly in humans. What follows is a short but
representative review of the literature.
Oregano Oil Treats Intestinal Parasites
This
first study found that the administration of oregano oil (oreganum
vulgare) consumed orally for 6 weeks was effective at curing enteric
(intestinal) parasite infections in humans. Fourteen participants
were used in this study all of whom tested positive for the enteric
parasites Blastocystis
hominis, Entamoeba
hartmanni,
and Endolimax
nana.
The authors report that: “there
was complete disappearance of Entamoeba hartmanni (four cases),
Endolimax nana (one case), and Blastocystis hominis (eight cases).
Also, Blastocystis hominis scores declined in three additional cases.
Gastrointestinal symptoms improved in seven of the 11 patients who
had tested positive for Blastocystis hominis.” This
paper is important because it establishes the antiparasitic
properties of oregano in humans.
Inhibition
of enteric parasites by emulsified oil of oregano in vivo.
Force
M, Sparks WS, Ronzio RA.
Phytother
Res., 2000 May, 14(3), 213-214.
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Oregano Oil Kills Microorganisms in the Laboratory
The
next paper is not in human study, but it does establish that oregano
oil is effective at killing microorganisms. The authors experimented
in the lab with several essential oils, to see how effective they
were against a wide variety of bacteria, molds, and yeasts, and found
that “of
the tested compounds, cinnamaldehyde, thymol, and carvacrol showed
the strongest antimicrobial effectiveness”.
Vapor-phase
activities of cinnamon, thyme, and oregano essential oils and key
constituents against foodborne microorganisms.
López
P, Sanchez C, Batlle R, Nerín C.
J
Agric Food Chem., 2007 May 30, 55(11), 4348-4356.
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Oregano Oil Cures Fatal Yeast (Candida) Infections in Mice
Oregano oil kills yeast (Candida albicans), and
when mice were infected with 5 times the lethal dose of the
infectious Candida yeast, 80% of them survived.
Antifungal
activities of origanum oil against Candida albicans.
Manohar
V, Ingram C, Gray J, Talpur NA, Echard BW, Bagchi D, Preuss HG.
Mol
Cell Biochem., 2001 Dec, 228(1-2), 111-117.
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Oregano Oil Successfully Treats Upper Respiratory Tract Infections
The previous three studies should be enough to
indicate what’s going on with oregano. In humans and in the
laboratory, oregano kills a wide range of microorganisms. The third
study listed above demonstrates that the antiseptic properties of
oregano can be profound, meaning the difference between life and
death for the mice in that study.
This
next study gets right to the heart of the matter. The study
investigated the effect of a nasal spray consisting of several
essential oils including oregano oil in 60 humans with upper
respiratory tract infections (the sore throat and congested lung
infections that often accompany a cold). This study is of the highest
calibre, as it is a randomized, double-blind, placebo-controlled
trial. The patients were split into two groups, one group received
the treatment while the other group received a placebo. Neither the
patients nor the doctors and nurses who interacted with them knew
which patients received the treatment, and which did not. (The best
medical studies are done this way so that the observations and
results will reflect only the results of treatment, and will not be
affected by biases that the doctors or patients may have for, or
against, the treatment.) The statistical analysis showed that 20
minutes following the treatment, the patients who had received the
treatment reported a greater improvement in symptom severity compared
to participants in the placebo group. They describe their nasal spray
as providing a “significant
and immediate improvement in symptoms of upper respiratory ailment”.
Treatment
of upper respiratory tract infections in primary care: a
randomized study using aromatic herbs.
Ben-Arye
E, Dudai N, Eini A, Torem M, Schiff E, Rakover Y.
Evid
Based Complement Alternat Med., 2011, 690346.
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Oregano Oil and the Immune System
This next study is interesting because it
establishes a link between oregano oil and the boosting of the immune
system. In this study oregano oil was fed to nursing pigs. (Again,
this was a placebo-controlled study, so half of the pigs received
oregano oil supplementation, and other half did not. The results were
found by comparing the two groups.) The oregano oil increased the
number of white blood cells in the pigs’ milk, which strongly
suggests that it boosted the immune system of the pigs. What’s also
interesting is that the piglets of the mothers who received oregano
oil, drank more milk, demonstrating a positive effect for the
children of nursing mothers who take oregano oil supplements. (The
piglets weren’t directly given any oregano oil, they only received
its benefit through their mothers’ milk.)
Effect
of dietary supplementation of oregano essential oils to sows on
colostrum and milk composition, growth pattern and immune status
of suckling pigs.
Ariza-Nieto
C, Bandrick M, Baidoo SK, Anil L, Molitor TW, Hathaway MR.
J
Anim Sci., 2011 Apr, 89(4), 1079-1089.
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Oregano Oil and Cholesterol
Getting away from colds and sinus infections
for a moment, I think the following paper is interesting. This paper
presents a study of orally taken oregano in hyperlipidemic human
patients. (Hyperlipidaemiajust means that these people have elevated
levels of fat in their blood, for example too much cholesterol.)
After regularly taking oregano oil supplements following each meal
for 3 months, these patients had improved lipid profiles including
higher HDL (good cholesterol), lower LDL (bad cholesterol), improved
antioxidant status (which, theoretically, could help fight cancer and
reduce heart disease), and improved endothelial function (healthier
veins and arteries) compared to those who did not take the oregano
supplement.
Effects
of Origanum onites on endothelial function and serum biochemical
markers in hyperlipidaemic patients.
Ozdemir
B, Ekbul A, Topal NB, Sarandöl E, Sağ S, Başer KH, Cordan J,
Güllülü S, Tuncel E, Baran I, Aydinlar A.
J
Int Med Res., 2008 Nov-Dec, 36(6), 1326-1334.
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Oregano Oil and Cancer
This
next paper is really about the cancer fighting qualities of rosemary
extracts, but does make this interesting statement in the
abstract: “One
study in particular observed an inverse relationship between
consumption of Mediterranean herbs such as rosemary, sage, parsley,
and oregano with lung cancer.” The
author of this paper is definitely more interested in rosemary, but
it’s interesting to see oregano described as a potential cancer
fighter.
Carnosol:
a promising anti-cancer and anti-inflammatory agent.
Johnson
JJ.
Cancer
Lett., 2011 Jun 1, 305(1), 1-7.
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More: Oregano and Cancer
This
paper tested an extract from Moroccan oregano (Origanum
compactum Benth.)
against a laboratory strain of human breast cancer cells and found
the oregano extract to be effective at killing the cancer. A
laboratory-bench experiment should not be viewed in the same light as
a proper clinical trial with human patients, but nevertheless this
provides a further indication that oregano may have cancer fighting
properties.
Antiproliferative
effect of extracts from Aristolochia baetica and Origanum
compactum on human breast cancer cell line MCF-7.
Chaouki
W, Leger DY, Eljastimi J, Beneytout JL, Hmamouchi M.
Pharm
Biol., 2010 Mar, 48(3), 269-274.
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Oregano Oil Review Paper: The Big List of Health Benefits
It is probably wise to view laboratory-bench
research as a little less relevant, simply because it’s so removed
from real human physiology (cells in a Petrie-dish just aren’t the
same thing as cells in a human body). The “gold-standard” on the
other hand, is high-quality placebo-controlled, double-blind studies
using human patients. But there is an important third kind of
research paper that is probably as important as the high-quality gold
standard studies are, and these are the review papers. Review papers
collect and interpret the results of many (usually gold-standard)
studies, and thus can draw conclusions and provide perspectives that
individual studies cannot.
The last paper we shall cover is a review paper
that lists a wide range of beneficial health effects due to oregano,
and in particular carvacrol. The properties of oregano include:
-
antimicrobial and antiparasitic (kills
microorganisms like bacteria, fungi, and yeasts, and parasites)
-
insecticidal (kills and repels insects)
-
antitumor (effective against cancer),
-
antimutagenic and antigenotoxic (help reduce
damage to one’s DNS),
-
analgesic (naturally relieves pain),
-
antispasmodic (relieves spasms),
-
anti-inflammatory (reduces inflammation and
discomfort associated with infection),
-
angiogenic (aid to the formation of new blood
vessels),
-
antiplatelet (aids blood situation),
-
AChe inhibitory (can help against Alzheimer’s
disease, and Glaucoma),
-
antielastase (counteracts poison),
-
antihepatotoxic (detoxes the liver),
-
hepatoprotective (protects the liver), and,
-
aids in gastrointestinal ailments.
antimicrobial and antiparasitic (kills
microorganisms like bacteria, fungi, and yeasts, and parasites)
insecticidal (kills and repels insects)
antitumor (effective against cancer),
antimutagenic and antigenotoxic (help reduce
damage to one’s DNS),
analgesic (naturally relieves pain),
antispasmodic (relieves spasms),
anti-inflammatory (reduces inflammation and
discomfort associated with infection),
angiogenic (aid to the formation of new blood
vessels),
antiplatelet (aids blood situation),
AChe inhibitory (can help against Alzheimer’s
disease, and Glaucoma),
antielastase (counteracts poison),
antihepatotoxic (detoxes the liver),
hepatoprotective (protects the liver), and,
Biological
and pharmacological activities of carvacrol and carvacrol bearing
essential oils.
Baser
KH.
Curr
Pharm Des, 2008, 14(29), 3106-3119.
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