Garlic has been an important herbal remedy for
centuries. Found in carvings and paintings on
the walls of Egyptian tombs, dating from 3700
BC, garlic's uses as a remedy for cancer and
other ailments are recorded in detail in Egyptian
medical documents, dating from 1550 BC.
Modern studies and human observations have validated
many medicinal effects of garlic and its potential to help
lower the risk of various ailments, including colon cancer. The
cancer preventive mechanisms of garlic, shown largely through
research using KyolicTM Aged Garlic Extract® (AGE), an odorless
supplement made from organic garlic by Wakunaga of America,
are largely due to potent antioxidants, a high content of
organosulfur compounds, an ability to stimulate immunological
responsiveness, detoxify carcinogens, inhibit inflammation and
prevent mutations that may lead to cancer.
Epidemiological Studies
Several population studies have found an association between
a high intake of garlic and a reduced risk of certain cancers,
including stomach and colon cancer. An analysis of the results
of these studies, showed, that the higher the amount of garlic
consumed, the lower the risk of stomach and colon cancer.
The "Iowa Women's Study"1 is a large prospective study
investigating whether diet and other risk factors are related to
cancer incidence in older women. Results of the study showed
a strong association between garlic consumption and colon
cancer risk. There was a 50 percent lower risk of colon cancer in
women who consumed the highest amounts of garlic, compared
to those consuming a low level.
Several population studies conducted in China and Italy
also showed repeatedly that consumption of allium vegetables,
onions and especially garlic was associated with a reduced risk
of stomach and colon cancer, sometimes as low as 50 percent.
The Nature of Colon Cancer
Colon Cancer is the third leading cause of deaths in the United
States. It is a multistage disease that is initiated by a series of
mutations in DNA that give rise to adenomatous polyps, of a
benign nature, that may progress to full blown cancer. Colon
cancer can have hereditary components, and is found in
families, but external factors including environmental factors,
lifestyle and diet play important role in the development of the
disease.
Colon cancer develops slowly, over a period of 10 to 15
years; though people over 50 are most prone to getting the
disease, colon cancer can develop at any age. The disease
usually begins as a non-cancerous polyp that can progress
with time into cancer, screening by colonoscopy is effective in
lowering the cancer risk and increasing the chance for cure, by
detecting and removing emerging adenomatous polyps. Cancer
screening by colonoscopy is recommended starting at the age
of 50, though people with a family history of the disease may
begin at an earlier age and be tested more often.
Diet and Lifestyle in Prevention
While screening is important in reducing risk, diet and lifestyle
are critical in supporting the body's natural defenses, helping
prevent the onset and growth of polyps and blocking their
subsequent development into colon cancer.
Leading a physically active life, maintaining a healthy
weight, not smoking and reduced levels of alcohol are important
aspects of prevention; as diet goes, a diet rich in plant food,
low levels of red meat and intake of milk products that contain
calcium and vitamin D are some of the recommendations by
the American Cancer Society.
Among the plant foods that have been associated with
lowering the risk of colon cancer, garlic ranks as a highly
effective protector. In some people a high consumption of
fresh garlic may cause gastrointestinal adverse effects; such
occurrences and the fact that the odor of garlic lingers on the
skin and breath, prevents many from taking advantage of its
health effects. Many have therefore turned to the odorless
supplement Kyolic Aged Garlic Extract (AGE), as an effective
way to seek protection against colon cancer. Currently, with over
700 scientific and medical publications showing the wide range
of AGE health benefits, this odorless garlic supplement is the
most researched and popular garlic supplement.
AGE a Natural Protectant against Colon Cancer
Kyolic Aged Garlic Extract (AGE), is produced by the Wakunaga
Company from organically grown garlic, using a process of aging
and extraction, at room temperature, for 20 months. Harsh
volatile garlic components, such as allicin, are converted by this
process to stable compounds, such as S-allyl cysteine, S-allyl
mercaptocysteine and others. S-allyl cysteine is the major watersoluble
organosulfur compound in AGE; it is a highly bioavailable
and is used to standardize AGE, assuring quality control. The
high quality control of AGE insures consistent efficacy in helping
sustain consumer health, remaining the choice garlic preparation
in clinical studies and research on the health effects of a garlic.
AGE lacks harsh or toxic compounds, and can be ingested safely
for years, for its health effects.
The wide range of AGE¡¦s anticancer actions has been
reported in studies using model systems. Findings show that
AGE and its organosulfur constituents inhibited colon cancer
in a dose-dependent manner. In addition, AGE stimulated
colon and liver glutathione S-transferases, enzymes assist in
detoxifying carcinogens. Other studies have shown that AGE
and its compounds with their high antioxidant action show anti-carcinogenic
actions by scavenging toxic reactive oxygen species,
unstable molecules that are waste products in metabolism, which
have the ability to trigger cancer-mutations in DNA. Other effects
of AGE found experimentally, were an inhibition of the binding
of carcinogens to DNA, detoxifying carcinogens, blocking the
proliferation of colon cancer cells and killing them by apoptosis,
a mechanism of programmed cell death.
Human Studies
While epidemiological studies have shown the efficacy of garlic
in lowering colon cancer risk, and experimental models found
AGE and its components, largely water soluble S-ally cysteine
and S-allyl-mercaptocysteine have anti-carcinogenic effects, the
protective action of AGE and its efficacy in lowering the risk of
colon cancer in humans had to be established by a clinical study.
To determine a potential protection against colon cancer
in humans, Tanaka2 and colleagues carried out a randomized, double-blind, clinical trial, using high intake of AGE (AGE 2.4 ml/day) as an active treatment and low-dose AGE (AGE 0.16
ml/day) as a control.
The study enrolled 51 patients who were diagnosed with
adenomatous polyps. Investigators assigned the patients
randomly to two groups, after removing adenomas that
were larger than 5 mm in diameter. Using colonoscopy, the
investigators determined the number and size of adenomas
before the patients began the intake of AGE (0 months) and
at six and twelve months after intake. There were thirty-seven
patients who completed the study; 19 in the active group,
receiving AGE and 18 in the control group, receiving placebo.
The investigators found that in the control group the number
of adenomas increased in linear fashion from the beginning of the
study (baseline point); by contrast, in the group taking the high
dose of AGE the size and number of adenomas were significantly
suppressed, after the 12 months of treatment. These findings
showed that the intake of Kyolic AGE has the potential to protect
humans against colon cancer, by preventing the progression of
precancerous colon adenomas into colon cancer.
The clinical study, showing AGE as a supplement with
potential preventive effects against human colon cancer, adds to
the results of several epidemiological studies showing a reduction
of colon cancer by high garlic consumption.
At this point, with overwhelming evidence of garlic protection
against colon cancer, it should be noted that a recent single
prospective study from Harvard Medical School3, did not find a
protective effect by the intake of fresh garlic. The study did not
include AGE.
To possibly understand the discrepancy in results, it should
be realized that the findings of efficacy by AGE in inhibiting the
growth of precancerous adenomas and potentially inhibiting
colon cancer, is partly due to the high standardization of its active
ingredients. This is in contrast to fresh garlic cloves that cannot
be standardized in the same way.
Depending on the conditions of their cultivation, garlic
bulbs may contain up to 33 different lipid- and water-soluble
organosulfur compounds, with varying inhibitory effects on colon
cancer, as shown in laboratory studies.
In a prospective study, unknown are the number of bulbs (that
means the dose of garlic components), that would be required for
human intake to have an inhibitory effect on colon cancer. Food
preparation methods are known to affect the potency of sulfur
compounds in garlic. For example, microwave heating and oven
cooking block the anti-cancer activity of some compounds in the
fresh garlic. The Harvard study had no biomarkers that reflected
the actual active garlic component in the human body.
By contrast, AGE is prepared at room temperature, with
no heating in the process of its production, preserving its anticancer
activity; in addition, S-allyl cysteine, the most prevalent
organosulfur compound in AGE, has been shown experimentally
to have a 98 percent bioavailability; this means it can be used
potentially as a marker to reflect the intake of Aged Garlic Extract
components.
References:
- Steinmetz KA, KushiLH, Bostick RM, et al Vegetables, fruit and colon cancer in the Iowa Women's Health Study. Am J. Epidemio.1994: 139:1-13.
- Tanaka S, Haruma K, Yoshihara M, Kajiyama G, Kira K, et al. Aged garlic extract has potential suppressive effect on colorectal adenomas in humans. J Nutr. 2006; 136:821S-826S.
- Meng S, Zhang X, Giovannucci EL, et al No association between garlic intake and risk of colorectal cancer. Cancer Epidemiol. In Press; On line Dec 12 2012.
