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New Research Links H. Pylori Infection
and Gastric Cancer
by Jim English and Ward Dean, MD
Helicobacter pylori (H. pylori) is a
tiny bacterium that was completely unheard of twenty years ago.
Today, H. pylori is known to afflict almost two-thirds
of all humans, and is recognized as the most prevalent form of bacterial
infection in the world. (1)
Residing in the stomach and duodenum of infected
individuals, H. pylori is a spiral-shaped bacterium that
has been strongly implicated in the development of gastrointestinal
inflammation (gastritis) and gastric and duodenal ulcers. Now, new
research strongly implicates H. pylori as the primary agent
for development of gastric (stomach) cancer. Gum mastic is a natural
substance from the sap of the Mediterranean evergreen tree, Pistacia
lentiscus. Mastic gum has been shown to be effective in protecting
the digestive system, healing peptic and duodenal ulcers, and eradicating
H. pylori from the gut. Although it has not been clinically
tested for this purpose, mastic gum offers a remarkable potential
to effectively prevent stomach cancer.
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Gastric (stomach) and duodenal ulcers were once
thought to be caused by spicy foods, stomach acid, and stress. This
view was radically altered in 1982, when researchers in Australia
discovered a new form of gram-negative bacteria in the stomach of
patients with gastritis. (2) Dr. Robin Warren, a pathologist at
the Royal Perth Hospital in Western Australia, first reported the
unique spiral-shaped bacterium in biopsy specimens from patients
with gastritis. Later, Warren and fellow Perth researcher Barry
Marshall reported the presence of the new bacterium in virtually
every biopsy specimen of 100 patients with duodenal ulcers.
Predictably, traditional gastroenterologists initially
rejected these new findings. In response to his critics, Warren
swallowed a liquid culture of the bacteria, hoping to prove that
H. pylori was the cause of peptic ulcers. Within weeks,
he was diagnosed with a full-blown case of self-induced gastritis,
proving his hypothesis was correct. In October, 1989, the new bacterium
(previously called Campylobacter pylori) was officially
recognized as a new genus and, due to its ability to occasionally
take on the shape of a helix, given the new name Helicobacter
(Fig. 1).
Prior to the discovery of H. pylori, the stomach was thought
to be a sterile environment. Indeed, a constant flood of digestive
enzymes and concentrated hydrochloric acid makes the gut an extremely
hostile environment for most pathogens. But research has revealed
that H. pylori is uniquely adapted to take advantage of
the hellish digestive brew. First, H. pylori uses its spiral
shape and several whip-like tails (flagellae) to drill into the
gastric mucosa –the mucus lining that protects the stomach
and keeps it from being dissolved by its own gastric juices. Simultaneously,
H. pylori produces a potent enzyme on its outer surface
called urease. Urease protects H. pylori from being destroyed
by gastric juices. Urease also disrupts the gastric mucus lining,
making it easier for the bacteria to penetrate the layer and attach
to the stomach and duodenum. Urease also protects H. pylori
by converting urea (which is abundant in saliva and gastric juices)
into a pair of strong bases—ammonia and bicarbonate. These,
in turn, neutralize gastric acids—in effect, creating a protective
antacid barrier around H. pylori.
H. pylori also defends itself from another
immediate threat—the human immune system. The immune inflammatory
response involves the production of vast numbers of neutrophils
that are mobilized to destroy invading pathogens. Safely ensconced
behind its mucus and antacid barriers, H. pylori is protected
from attack by the immune system which cannot penetrate the mucus
lining. Additionally, H. pylori produces another enzyme
called catalase that further protects the bacteria from neutrophils.
The result is that instead of repelling H. pylori, the
immune inflammatory response causes severe damage to the stomach
lining, thus contributing to gastritis and ulcer formation. (3)
While it is known that humans serve as the natural host of H.
pylori, the exact mechanism of transmission is still unclear.
Most researchers believe that infection occurs via oral-oral (kissing)
or fecal-oral (food or water contamination) transmission. (4) In
the United States only 20 percent of the population under 40 years
of age is infected. But since infection continues to spread with
time, the rate grows with each passing year until 50 percent of
all US citizens over the age of 60 are infected. The infection problem
is even greater outside of the US, with infection beginning early
in childhood, leading to adult rates of infection approaching 90
percent in some parts of Asia and Africa. (5)
While many infected people may never show any
symptoms, H. pylori is strongly associated with a number
of gastrointestinal diseases, including chronic active, chronic
persistent, and atrophic gastritis. Additionally, H. pylori
infection is established to be a major cause of gastric ulcers (6)
and up to 80% of all duodenal ulcers are blamed on H. pylori
infection. (7) Since the immune system is helpless to control H.
pylori, unless eradicated by other means, infection generally
lasts a lifetime.
Gastric cancer is the second most common cancer worldwide. In certain
countries, such as Colombia and China, where H. pylori
infects over half the population in early childhood, gastric cancer
is the most prevalent form of cancer. (8) According to the National
Institutes of Health (NIH) about 24,000 people in the United States
are diagnosed with stomach cancer each year. (9) Of these, about
14,000 will die from the disease.
Data gathered from population studies had previously
found an association between H. pylori infection and later
development of a number of diseases, including 1) gastric mucosa-associated
lymphoid tissue (MALT), 2) MALT lymphoma, 3) gastric cancer, 4)
pancreatic cancer, 5) ischemic heart disease, 6) ischemic cerebrovascular
disease, 7) atherosclerosis, 8) periodontal disease, and 9) skin
diseases such as rosacea. (10)
Now, new research published in the September 13,
2001 issue of the New England Journal of Medicine confirms
the hypothesis that H. pylori is the primary agent for
the development of stomach cancer.
H. pylori infection rates are much higher in Japan than
in the US. Each year gastric cancer develops in 300,000 (0.5 percent)
of the estimated 60 million infected with H. pylori. To
study the link between H. pylori and stomach cancer, Japanese
researchers enrolled 1,526 patients who suffered from ulcers, gastric
hyperplasia, or non-ulcer dyspepsia (ulcer-like pain, but no ulcer).
The study included 869 men and 657 women with an average age of
52 years. Patients underwent endoscopic biopsy at the time of enrollment,
and at three years to assess H. pylori infection. They
were monitored for an average of 7.8 years. Of the 1526 enrolled
patients, a total of 1,246 (82%) were found to be infected with
H. pylori. (11)
Over the course of the study 36 patients (2.9
percent) from the infected group developed stomach cancer. Gastric
cancer did not develop in any of the uninfected patients. The researchers
report that certain forms of gastric disturbance were associated
with a higher risk of gastric cancer. Those patients most at risk
were those with severe gastric atrophy (shrinkage and weakening
of the stomach), gastritis (stomach inflammation), and abnormal
intestinal tissue changes.
The researchers concluded that gastric cancer
develops in persons infected with H. pylori, but not in
uninfected persons. An accompanying editorial published in the September
13, 2001 New England Journal of Medicine stated that the
findings "substantially bolsters evidence of the association"
between H. pylori and gastric cancer, and suggest that
"in the future, physicians may need to view H. pylori...as
something akin to tobacco." (12)
Current medical protocols for eliminating H. pylori infection
usually consists of a combination of one or two antibiotics (metronidazole,
tetracycline, clarithromycin, amoxicillin), H2 blockers (cimetidine,
ranitidine, famotidine, nizatidine), proton pump inhibitors (omeprazole,
lansoprazole, rabeprazole) and bismuth subsalicylate, a stomach-lining
protector. (10)
While these therapies can be effective, they are
complex to administer, and are naturally expensive. Successful eradication
of H. pylori is frequently compromised by patient noncompliance
caused by unpleasant side effects (nausea, diarrhea and vomiting)
and high costs of the drugs. Antibiotic resistance is also a growing
problem that complicates treatment and increases risk of reinfection.
(13)
For centuries, mastic gum has been used by traditional healers to
treat stomach upset, ulcers, and heartburn. Modern research supports
the use of mastic to restore and maintain proper gastrointestinal
and digestive function. Research has shown that mastic is clinically
effective in the treatment of benign gastric ulcers (14) and duodenal
ulcers. In one double-blind clinical trial, researchers found that
oral doses of one gram per day of mastic over a period of two weeks
produced symptomatic relief in 80 percent of patients with duodenal
ulcers. The study also found endoscopic evidence that mastic promoted
the healing of gastric mucosal tissues. Ulcers were completely replaced
with healthy epithelial cells. (15) Animal studies have also found
that mastic possesses cytoprotective (cell protective) and antisecretory
properties, and that it can reduce gastric mucosal damage caused
by anti-ulcer drugs and aspirin. (16)
Researchers writing in the December 24, 1998 issue of the New England
Journal of Medicine reported that mastic is an effective antibacterial
agent for the treatment of H. pylori. In the report the
authors stated that, "Even low doses of mastic gum —
one gram per day for two weeks — can cure peptic ulcers very
rapidly… We have found that mastic is active against Helicobacter
pylori, which could explain its therapeutic effect in patients with
peptic ulcers." (17)
The researchers conducted in vitro tests that
revealed that mastic was effective in killing 99.9 percent of H.
pylori when tested against seven different strains—NCTC
11637 (a standard reference strain) and six clinical isolates, including
three resistant to metronidazole. Of note was the finding that mastic
was equally effective against the drug resistant strains of H.
pylori, even at very low concentrations. "These results
suggest that mastic has definite antibacterial activity against
H. pylori. This activity may at least partly explain the
anti–peptic ulcer properties of mastic.'"
Mastic is an affordable and safe natural supplement that protects
the digestive system, heals peptic and duodenal ulcers, and eradicates
H. pylori from the gut. H. pylori is linked with
gastrointestinal inflammation (gastritis) and gastric and duodenal
ulcers. Research also implicates H. pylori as the primary
agent for development of gastric stomach cancer. Gum mastic, because
of its ability to eradicate H. pylori, may effectively
prevent this common form of deadly cancer.
References
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ulcer. J Clin Exp Pharm Physiol 1984;11:541-4.
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